Abstract
The present invention relates to an integrated raise caving mining method for mining deposits in rock mass comprising: developing at least one raise (102,102a-f,202,302a-g,402a-e) in the rock mass (10), developing a drawbell (100,100a-c, 200a-g,300a-f,400a-e) in the rock mass (10), wherein at least a portion of the drawbell is excavated from the at least one raise (102,102a-f,202,302a-g,402a-e), initiating caving through undercutting, wherein at least a part of an undercut is created by gradually expanding the drawbell (100,100a-c, 200a-g,300a-f,400a-e) in upwards direction by excavation, developing at least two drawpoints (106,206,406) into the drawbell (100,100a-c, 200a-g,300a-f,400a-e), wherein the drawpoints (106) are developed from drifts (115,207,407) arranged on different levels and progressively drawing fragmented rock (101) from the at least one drawbell through the drawpoints (106,206,406).
Claims
1-88. (canceled)
89. An integrated raise caving mining method for mining deposits in rock mass comprising: developing at least one raise in the rock mass, developing a drawbell in the rock mass, wherein at least a portion of the drawbell is excavated from the at least one raise, initiating caving through undercutting, wherein at least a part of an undercut is created by gradually expanding the drawbell in upwards direction by excavation, developing at least two drawpoints into the drawbell, wherein the drawpoints are arranged on different levels, and progressively drawing fragmented rock from the at least one drawbell through the drawpoints.
90. The integrated raise caving mining method according to claim 89, further comprising caving the rock mass located above the drawbell, thereby forming a caving stope.
91. The integrated raise caving mining method according to claim 89, wherein the portion of the drawbell is excavated by drilling blast holes into the rock mass around the raise by operating a machinery arranged inside the raise, and blasting the rock mass by charging and detonating explosives in those blast holes such that the portion of the drawbell is blasted.
92. The integrated raise caving mining method according to claim 89, comprising pre-conditioning of rock mass located above the drawbell roof by operating the machinery arranged inside the at least one raise.
93. The integrated raise caving mining method according to claim 89, wherein at least a part of the undercut is created by gradually expanding the drawbell in the upwards direction without increasing the length of the perimeter of the drawbell roof.
94. The integrated raise caving mining method according to claim 89, wherein the complete drawbell is developed by excavation from the at least one raise.
95. The integrated raise caving mining method according to claim 89, wherein the at least one raise is developed to extend over only a part of the stope height above the drawbell.
96. The integrated raise caving mining method according to claim 89, wherein the at least one raise is developed to extend over the full stope height.
97. The integrated raise caving mining method according to claim 89, wherein blasting takes place in an unconfined environment by drawing previously blasted rock from the drawbell to create a void.
98. The integrated raise caving mining method according to claim 89, wherein blasting takes place in a semi-confined environment by drawing previously blasted rock from the drawbell without creating a void.
99. The integrated raise caving mining method according to claim 89, further comprising switching from caving to drilling and blasting on demand.
100. The integrated raise caving mining method according to claim 89, further comprising re-initiating caving of the stope pre-breaking by drilling, charging and blasting in a part of the stope in specific areas from inside the raise by operating the machinery arranged inside the raise in case caving has stalled.
101. The integrated raise caving mining method according to claim 89, further comprising controlling the cave progression by performing controlling measures means arranged from inside the raise.
102. The integrated raise caving mining method according to claim 89, further comprising controlling cave progression by operating machinery arranged inside the raise and/ or by draw strategy and/ or draw control.
103. The integrated raise caving mining method according to claim 89, further comprising developing at least one additional drawpoint into the drawbell and developing said at least one additional drawpoint on the same level as pre-existing drawpoints or on a different level than pre-existing drawpoints to stimulate material flow in the drawbell.
104. The integrated raise caving mining method according to claim 89, further comprising developing at least one drawpoint into the stope arranged above the drawbell.
105. The integrated raise caving mining method according to claim 89, further comprising providing the at least one drawbell with multiple drawpoints distributed over at least two levels and distributing said drawpoints evenly such that a favourable drawpoint spacing is achieved and drawing said drawpoints interactively such that interaction between isolated draw zones is achieved.
106. The integrated raise caving mining method according to claim 89, further comprising joining at least two drawbells and forming a coherent stope above the drawbells, and caving the coherent stope.
107. The integrated raise caving mining method according to claim 89, further comprising enlarging the caving stope in lateral direction by developing an additional drawbell at a location next to the caving stope and joining the additional drawbell to the caving stope.
108. The integrated raise caving mining method according to claim 89, further comprising monitoring of caved rock mass by using a remote-controlled monitoring device arranged inside the raise.
109. The integrated raise caving mining method according to claim 89, further comprising monitoring of the caving stope and/ or the cave back and/ or the caved rock masses by remote controlled monitoring means which is lowered through the raise and into the caving stope.
110. The integrated raise caving mining method according to claim 89, further comprising determining of pre-conditioning needs based on monitoring of spatial distribution and/ or behavior of individual formations and zones.
111. The integrated raise caving mining method according to claim 89, wherein the mine layout and infrastructure position are adapted to and determined by production and/or ore body geometry and/or rock mechanics consideration and/ or ore flow considerations.
112. The integrated raise caving mining method according to claim 89, wherein the interaction between at least two adjacent stopes generate a regional favourable stress environment for mining infrastructure.
113. An integrated raise caving mining infrastructure configured for mining deposits in a rock mass, which integrated raise caving mining infrastructure comprises; at least one raise developed in the rock mass; a drawbell developed in the rock mass, wherein at least a portion of the drawbell is joined to the at least one raise; an undercut (UC) being configured to initiate caving of rock mass located above the undercut, wherein at least a portion of the undercut is formed as a part of the drawbell; wherein said portion has been created by gradually expanding the drawbell in upward direction by excavation; at least two drawpoints joined to the drawbell, wherein the drawpoints are joined to drifts arranged on different levels; and a transport device configured to progressively draw fragmented rock from the drawbell.
114. The integrated raise caving mining infrastructure according to claim 113, wherein a caving stope is located above the drawbell.
115. A monitoring system configured for monitoring an integrated raise caving mining infrastructure configured for mining deposits in rock mass according to claim 113, which monitoring system comprises: monitoring means for monitoring development of a developed in the rock mass, wherein at least a portion of the drawbell is joined to the at least one raise; monitoring means for monitoring development of an undercut (UC) being configured to initiate caving of rock mass located above the undercut, wherein at least a portion of the undercut is formed as a part of the drawbell; wherein said portion has been created by gradually expanding the drawbell in upward direction by excavation; monitoring means configured for monitoring the initiation of caving of the rock mass; monitoring means configured for monitoring a caving stope; and wherein the monitoring system is configured for remote-controlled monitoring of the caving stope and/ or a cave back forming a zone of fractured rock mass and/ or caved rock masses; and wherein the monitoring system is configured to communicate with and be operated by an automatic or semi-automatic control system according to claim 40 in remote control mode and/or in automatic control mode and/or in semi-automatic control mode; and wherein the monitoring system is configured for collecting monitoring data, analysing monitoring data, storing monitoring data, and transmitting monitoring data via wireless and/ or wired communication devices to an automatic or semi-automatic control system of the integrated cave mining infrastructure.
116. The monitoring system according to claim 115 wherein the monitoring system is configured for monitoring of caved rock mass by using a remote-controlled monitoring device arranged inside the raise.
117. The monitoring system according to claim 115 wherein the monitoring means is arranged inside the raise to monitor the mining operation, and being lowered through the raise into the cave to enable monitoring of for example cave back, fragmentation, fracturing zone.
118. A machinery comprising: a movable platform, a drilling and/or charging device configured for; developing a drawbell in the rock mass, wherein at least a portion of the drawbell is excavated from the raise by drilling and/or charging by means of the machinery, thereby initiating caving through undercutting; developing the drawbell by gradually expanding the drawbell in upwards direction by excavation; and wherein the machinery is configured for drilling and/or charging the rock mass from inside the raise and the drilling and/or charging device is arranged on the movable platform, which is movable within the raise for reaching a position for operation of the drilling and/or charging device, and the platform is movable within the raise by being hoisted down to the position of operation.
119. The machinery according to claim 118, wherein the drilling and/or charging device comprises a drilling bore and/or charging equipment configured for initiating said caving.
120. The machinery according to claim 118, wherein the machinery further comprises pre-conditioning equipment.
121. The machinery according to claim 118, wherein the platform is configured with a modular design.
122. The machinery according to claim 118, wherein the machinery and/or equipment arranged on the platform is configured with a modular design.
123. The machinery according to claim 118, wherein machinery is configured to be operated by remote control and/ or by manual control.
124. The machinery according to claim 118, wherein the machinery is configured for semi-automation or full automation.
125. The machinery according to claim 118, wherein the machinery for drilling is configured for performing directional drilling.
126. The machinery according to claim 118, wherein the machinery for drilling (910) is configured for drilling curved boreholes by directional drilling.
127. The machinery according to claim 118, wherein the machinery is configured for blast initiation by wired detonators and/ or remote-controlled detonators and/ or non-electric detonators and/ or wireless detonators.
128. An automatic or semi-automatic control system of an integrated raise caving mining infrastructure according to claim, wherein the automatic or semi-automatic control system is electrically coupled to a control circuitry configured to control the integrated raise caving mining method according to claim 89, wherein the control circuitry comprises a data medium, configured for storing a data program P which is programmed for controlling the automatic or semi-automatic control system and/or for controlling the machinery and/or for communicating with the monitoring system.
129. The automatic or semi-automatic control system according to claim 128, wherein the automatic or semi-automatic control system comprises the machinery according to claim 118, wherein the machinery is configured to be operated by the automatic or semi-automatic control system in remote control mode and/or in automatic control mode and/or in semi-automatic control mode and/or manually controlled mode.
130. A data medium, configured for storing a data program (P), configured for controlling the automatic or semi-automatic control system according to claim 128 and/or configured for controlling the machinery according to claim 118, said data medium comprises a program code readable by the control circuitry for performing the integrated raise caving mining method according to claim 1 when the data medium is run on the control circuitry.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0252] To fully understand the present invention and further objects and advantages of it, the detailed description set out below should be read together with the accompanying drawings, in which the same references denote similar features in the various figures, and in which:
[0253] FIGS. 1a-c schematically illustrate in a vertical cross-section the basic principle of drawbell development according to the invention.
[0254] FIG. 1a illustrates a platform lowered into a raise for drilling and charging activities,
[0255] FIG. 1b illustrates the platform stored at top in hoist frame for blasting,
[0256] FIG. 1c illustrates excavation after blasting with void filled due to swell of blasted rock mass.
[0257] FIGS. 2a-2d schematically illustrate a vertical cross-section of one example of initiation of caving resulting from drawbell development as shown in FIGS. 1a-1c according to the invention.
[0258] FIGS. 3a-3d schematically illustrate a vertical cross-section of one example of initiation of caving resulting from development of more than one drawbell according to the invention.
[0259] FIGS. 4a-4c schematically illustrate a vertical cross-section of one example of enlarging of a caving stope in lateral direction according to the invention.
[0260] FIGS. 5a-5d schematically illustrate a vertical cross-section of one example of application of pre-conditioning measures according to the invention.
[0261] FIGS. 6a-6e schematically illustrate a vertical cross-section of one example of application of pre-breaking measures according to the invention.
[0262] FIGS. 7a-7d schematically illustrate a vertical cross-section of one example of application of pre-conditioning measures according to the invention.
[0263] FIGS. 8a-8c schematically illustrate isometric views of examples of alternatives of drawbell configurations according to the invention.
[0264] FIGS. 9a-9c schematically illustrate isometric views of examples of alternative drawbell development configurations according to the invention.
[0265] FIG. 10 schematically illustrates a horizontal cross-section of one example of advanced progress of mining a deposit with the integrated raise caving mining method according to the invention.
[0266] FIGS. 11a-11e schematically illustrate isometric views of one example of an implementation of the method according to the invention.
[0267] FIGS. 12a-12c schematically illustrate vertical cross-sections of examples of drawpoints and draw zones during production of the method according to the invention.
[0268] FIGS. 13a-13b schematically illustrates an example of an arrangement of isolated and interactive draw zones during production of the integrated raise caving mining method according to the invention.
[0269] FIG. 14 schematically illustrates an integrated cave mining infrastructure comprising an automatic or semi-automatic apparatus electrically coupled to a control circuitry;
[0270] FIG. 15 illustrates a flowchart showing an example of an integrated raise caving mining method;
[0271] FIG. 16 illustrates a flowchart showing a further example of an integrated raise caving mining method; and
[0272] FIG. 17 illustrates a control circuitry adapted to operate an automatic or semi-automatic control system of an integrated cave mining infrastructure, which automatic or semi-automatic control system is configured to perform any exemplary of the integrated raise caving mining method herein described.
DETAILED DESCRIPTION OF EMBODIMENTS AND EXAMPLES OF THE INVENTION
[0273] Examples and embodiments of the integrated raise caving mining method, the mine layout, and the mining sequence according to the present invention, will be described in the following with references to the figures.
[0274] For purpose of simplicity the rock mass is not shown in the figures but rather the raises, drawbells and drawpoints developed in the rock mass.
[0275] One important feature of the integrated raise caving mining method is the development of at least one drawbell from at least one raise and its successive transition to a caving process above the drawbell.
[0276] FIGS. 1a-1c schematically illustrate a vertical cross-section of a principle of drawbell development in a rock mass, herein also referred to as drawbell excavation, from a raise with mining equipment located inside the raise. FIG. 1a illustrates schematically the development of a drawbell 100 by drilling and charging carried out from the mining equipment, machinery 120, positioned on a platform 103, which is moved with a shaft hoist system 104 inside a raise 102. The platform 103 must be designed such that it can still be moved inside the raise 102, even in the case of rock mass deformations occurring in the raise.
[0277] The shaft hoist system 104 is located in a specifically excavated infrastructure excavation, which size and shape is adapted to the requirements of the hoist system and/ or rock mechanics considerations. In order to keep the infrastructure excavation of the hoist system 104 small, a modular design of the platform 103 and/ or machinery 120 mounted on the platform is advantageous. A small infrastructure excavation provides an improved stability. The modular design allows changing of utilized machinery quickly.
[0278] The machinery 120 mounted onto the platform 103 is adapted to operational requirements. Possible types of machinery comprise amongst others machinery for drilling, machinery for charging, machinery for support installation or machinery for hydraulic fracturing.
[0279] As shown in FIG. 1a, a raise 102 has already been developed from a drift in rock mass 10 by conventional techniques. The platform 103 and hoist system 104 are installed after development of the raise 102 is finished. The drawbell is gradually expanded in upwards direction by excavation such that a drawbell roof area becomes larger than a drawbell bottom area. The drawbell 100 is blasted in subsequent near horizontal slices of rock mass in upwards direction. The length, orientation, and inclination of drill holes 105 are adapted such that the shape of individual blast slices is adapted such that a drawbell of a specific predetermined shape can be formed. Drill holes may be drilled horizontally or inclined downwards or upwards. Downward inclined drill holes may achieve a better toe breakage. The drill holes 105 are drilled at a specific distance from an existing drawbell roof 118. After drill holes 105 are drilled and charged with explosives, the platform 103 is retracted to the top and stored in a safe position so that damage to the platform 103 resulting from blasting is avoided. FIG. 1b outlines the retracted and stored platform 103.
[0280] In another form of the invention, the platform 103 may also be stored by moving it aside from the top of the raise 102. Thus the platform is configured to be moved to the side at the top of the raise to be stored in a storage position.
[0281] The blast initiation can be carried out with different options, which comprise amongst others non-electric detonators, detonators initiated through an electric signal transferred via cable or detonators initiated wirelessly by means of communication through rock mass.
[0282] In another form of the invention, more than one slice could be blasted in a single blast. Thereby an appropriate time delay between individual slices is required.
[0283] FIG. 1c illustrates schematically that broken rock mass 101 falls into the drawbell 100 due to blasting, and that there must be enough void to absorb the swell of fragmented rock resulting from blasting. Before the next blast holes can be fired, enough broken rock mass must be drawn from the drawbell accordingly. Broken rock mass 101 is drawn through drawpoint 106. Either one or several drawpoints may be used to draw the broken rock mass 101 from the drawbell 100. However, only the swell is drawn out of the drawbell so that the formation of an excessively large void is avoided.
[0284] FIG. 1c further shows that drawbell 100 is expanded in the upwards direction without increasing the length of the perimeter of the drawbell roof such that the drawbell obtains a section 125 provided with a horizontal cross-section having constant or nearly constant area in upwards direction. Such section may for example serve as location for developing a drawpoint into the drawbell.
[0285] In the attached figures it should be noted that the shape of the drawbells and caving stopes are only schematic illustrations which are very much idealized for the purpose of simplification.
[0286] Furthermore, features like excavations, main infrastructure, hoist shafts, ore handling facility etc. which are required in all mining methods, are not shown.
[0287] FIGS. 2a-2d schematically illustrate a vertical cross-section of one example of initiation of caving resulting from drawbell development according to the invention.
[0288] FIG. 2a shows a drawbell 100, which is developed in rock mass 10 by excavation by drilling blast holes into the rock mass around the raise by operating a machinery 120 arranged on a platform (machinery and platform is not shown in figure) arranged inside the raise. The blast holes are charged by the machinery 120 and thereafter the rock mass is blasted by detonating explosives in those blast holes such that a portion of the draw bell is blasted. Excavation of the portion of the drawbell is performed by blasting slices of rock mass. Fragmented rock mass 101 is drawn at drawpoint 106 out of the drawbell 100. As drilling and blasting continues upwards, the shape of individual blast slices is adapted to form a drawbell 100 of specific shape. Local rock mass conditions, stress situation, ore flow considerations, as well as production demands influence its shape. Moreover, the area of the roof 118 of the drawbell 100 is gradually increased during drawbell development by means of drilling and blasting. FIG. 2b illustrates the increased drawbell roof area 118 in comparison with FIG. 2a. Additionally the gradual increase of the drawbell roof area is part of the undercutting process. At least a part of an undercut is created through gradually expanding the drawbell in upwards direction by excavation and increasing the roof area of the drawbell. This undercutting process initiates caving in the rock mass, after the area of the undercut rock mass exceeds a critical area. The critical area required for cave initiation is a function of rock mass properties, stress situation and the shape of the undercut area. FIG. 2b shows a drawbell 100, in which the drawbell roof area, which corresponds to the undercut area in the provided example, has not exceeded the critical area required for cave initiation yet. However, first fractures 107 developed and/ or discontinuities opened above the roof of the drawbell 100. Therefore, rock mass within the region of fractures 107 enters a yield state and rock mass properties deteriorate subsequently. The drill and blast design may be adjusted in this phase to adapt to the additional requirements caused by the yielding rock mass.
[0289] In FIG. 2c the roof area of the drawbell 100 has increased and exceeded the critical area required for cave initiation. Thus, caving process was initiated and progresses upwards. The rock mass located above the drawbell caves and a caving stope having a zone of fractured rock mass above the caving stope 108 forms. This zone of fractured rock mass 108 is characterized by development of fractures and/ or opening of discontinuities in the rock mass. The prevailing rock mass properties, stress conditions, and mine layout influence the extent and degree of fracturing inside the zone of fractured rock mass 108 significantly. The rock mass yields in the zone of fractured rock mass 108, finally detaches, and falls as broken rock mass 101 into the drawbell 100. The drawbell is provided with at least two drawpoints 106, which are developed on two different levels into the drawbell. Broken rock mass 101 is drawn from the drawbell through the drawpoints 106.
[0290] Consequently, a void 109 is created above the broken rock mass 101. This void 109 is required for cave progression. Rock mass from the zone of fractured rock mass 108 detaches and falls into the void. Broken rock mass 101 is finer than the in-situ rock mass and/ or rock mass in the fractured zone 108. Moreover, further comminution processes occur in the broken rock mass 101 which reduces particle size as broken rock mass flows towards the drawpoints 106.
[0291] Preferably, the drawbell 100 is configured to be oriented such that the infrastructure is positioned favorably related to the prevailing stress situation. However, in another alternative, the drawbell 100 is configured to be oriented such that cave initiation is facilitated by the prevailing stress situation.
[0292] FIG. 2c outlines one possible caving mechanisms. The shown caving mechanism is driven by stresses and a zone of fractured rock mass forms therefore above the caving stope. However, other caving mechanism may be active as well. Caving mechanisms may also occur in combination.
[0293] FIG. 2d illustrates that caving has progressed further upwards and thereby formed a stope 110 above the drawbell 100. The drawbell has been provided with tunnels on additional levels arranged on opposite sides of the drawbell. The additional levels are elevated above the bottom of the drawbell. Each level provides additional drawpoints 106 which are developed into the drawbell 100. Subsequent drawing of ore from the stope 110 through the drawbell 100 at drawpoints 106 increases the size of the void 109. To achieve a continuous caving process and for reasons of ore flow optimization the position of drawpoints 106 is critical. Thus, additional drawpoints 106 have been developed into the drawbell 100 and into the stope 110 above the drawbell to stimulate material flow in the drawbell and the caving stope. As shown, the additional drawpoints are developed from different directions into the drawbell, in this case on opposite sides of the drawbell. A sufficiently large void 109 must be formed below the stope roof, which corresponds to the cave back 119, so that further rock mass can detach from the zone of fractured rock mass 108. The zone of fractured rock mass 108 is now situated above the roof of the stope 110. However, the void 109 must also be kept to reasonable size to avoid the risk of an air blast. The size of the void 109, the broken rock mass 101 and/ or the zone of fractured rock mass may be monitored using the raise 102. Also, the cave progression and/ or direction of cave progression and the caving stope and/ or the cave back 119 may be monitored by monitoring means arranged inside the raise. The monitoring means may also be lowered through the raise into the caving stope which is advantageous.Due to continued draw of broken rock mass from the stope the cave continues to progress upwards. After caving reached the ore body boundaries, waste rock mass from the surrounding and/ or overlying rock mass formations starts caving into the stope. In the process of drawing the remaining ore from the stope, the stope is subsequently filled with waste rock mass.
[0294] In another embodiment of the invention, a caving stope may also be connected to a formerly mined out area or to the surface, which causes subsidence.
[0295] FIGS. 3a-3d schematically illustrate in a vertical cross-section one example of initiation of caving resulting from development of more than one drawbell.
[0296] FIG. 3a shows a developed drawbell 100a in rock mass 10. Machinery 120 (machinery not shown in figure) operating inside a raise 102a is used for development of drawbell 100a, which is filled with broken rock mass 101. Caving did not start above drawbell 100a.
[0297] FIG. 3b illustrates the development of a second drawbell 100b from raise 102b,
[0298] In FIG. 3c drawbell 100b is fully developed. Drawbells 100a and 100b are developed adjacent to each other. Drawbells 100a,b are used for undercutting. At least a part of an undercut is created through gradually expanding of the drawbells upwards in the vertical direction. The drawbells are excavated in height and width. The roofs of drawbells 100a,b are joined in order to form a large unsupported area, an undercut, which is larger than the critical area required for cave initiation. Consequently, a zone of fractured rock mass 108 forms above the roof of drawbells 100a,b and caving is initiated through undercutting. Rock mass detaches from the zone of fractured rock mass 108 and falls onto the broken rock mass 101, which is located in drawbells 100a,b. A void 109 must be present below the zone of fractured rock mass 108 to allow detachment of rock mass from the zone of fractured rock mass 108 and subsequent cave progression. Broken rock mass 101 is drawn at drawpoints 106 from drawbells 100a,b. Drifts 115,116 are oriented in different directions and provide access to drawpoints 106.
[0299] FIG. 3d shows the subsequent cave progression following cave initiation, which is outlined in FIG. 3c.
[0300] In FIG. 3d caving progressed in upwards direction and thereby forms a coherent stope 110, which is located above drawbells 100a and 100b. To enable cave progression, broken rock mass is drawn at drawpoints 106 developed into drawbells 100a,b. Drifts 115,116 are oriented in different directions and provide access to drawpoints 106. Thereby a void 109 is formed on top of the broken rock mass 101 in the stope 110 below the cave back 119. Thus, rock mass can detach from the zone of fractured rock mass 108 and can fall into the stope 110; and caving progresses in an upwards direction. Raises 102a,b may be used for monitoring purposes or cave inducement measures, for example different methods of pre-conditioning, or pre-breaking.
[0301] FIGS. 4a-4c schematically illustrate a vertical cross-section of one example of enlarging of the caving stope in lateral direction by means of developing of an additional drawbell next to the caving stope.
[0302] FIG. 4a shows a caving stope 110, which is filled with broken rock mass 101 and which has two drawbells 100a and 100b. Caving is progressing in upwards direction due to subsequent draw of broken rock mass through drawpoints 106 developed into drawbells 100a,b and due to subsequent detachment of rock mass 10 falling into the void 109 from the zone of fractured rock mass 108. Drifts 115,116 are oriented in different directions, and provide access to drawpoints 106. Depending on availability, all drawpoints 106 are in operation to facilitate drawing of rock mass from the drawbells. To increase the lateral extension of the stope 110 a drawbell 100c is developed next to the stope 110 by means of drilling and blasting conducted with machinery 120 (not shown in figure) operating in raise 102c. In FIG. 4a development has started of drawbell 100c.
[0303] In FIG. 4b drawbell 100c is fully developed. Caving is initiated above drawbell 100c and a zone of fractured rock mass 108 forms above drawbell 100c accordingly. Moreover, drawbell 100c is connected to the adjacent drawbell 100b.
[0304] FIG. 4c shows a more advanced stage of cave progression. The existing undercut established from drawbell 100a,b is widened in lateral direction as drawbell 100c is joined to the caving stope. Caving progresses in vertical direction above drawbells 100a,b,c, due to continuing draw of broken rock mass 101 at drawpoints 106. Drifts 115,116 are oriented in different directions and provide access to drawpoints 106. As drawbells 100a,b,c are adjacent and connected, the coherent stope 110 forms above drawbells 100a,b,c. Raises 102a,b,c may be used for monitoring or cave inducement measures.
[0305] As drawing of rock mass through drawbells continues, caving progresses into the waste rock mass, which starts to fill up the stope. Drawpoints and the corresponding drawbell are put out of operation and abandoned, after an unacceptable content of waste rock mass reports to the drawpoint. Accordingly, the affected drawbell is said to be depleted.
[0306] In another embodiment of the invention, adjacent drawbells may be configured such that they are of different shape and/ or size and/ or such that they are situated at different elevations.
[0307] The direction of cave progression as shown in FIGS. 2c,2d,3c,3d,4a,4b,4c is vertical. However, the cave progression direction depends on several parameters, which are amongst others the prevailing rock mass properties, their spatial distribution, the prevailing stress situation, the presence of large faults or shear zones, the presence of previously mined stopes and the implemented draw strategy.
[0308] FIGS. 5a-5d schematically illustrate a vertical cross-section of one example of the application of pre-conditioning measures to cave a competent rock mass formation.
[0309] FIG. 5a shows a developed drawbell 100 filled with broken rock mass 101. Caving is initiated and progresses upwards in vertical direction. A zone of fractured rock mass 108 is located above the stope 110. At some distance above the drawbell a competent rock mass formation 111 is prevailing. The position of this competent rock mass formation 111 is such that it will be part of the stope 110 as caving progresses further. This competent rock mass formation 111 does not cave readily due to its strength and caving may stall. To reduce the risk of a cave stall, pre-conditioning measures may be applied selectively in the rock mass above the stope roof and on-demand. FIG. 5a illustrates the application of such pre-conditioning measures. Drillholes 105 are drilled from machinery 120 (not shown in figure) operating inside the raise 102d into the competent rock mass formation 111 in the region, which should be caved afterwards. These drill holes 105 are subsequently used for application of pre-conditioning measures, such as for example hydraulic fracturing and/ or confined blasting. These pre-conditioning measures may be conducted from machinery situated on a platform inside the raise 102d.
[0310] FIG. 5b illustrates that caving progressed further and the stope 110 grew in a vertical direction. Moreover, the pre-conditioning measures were applied and created a pre-conditioned zone 112. It should be noted that pre-conditioning measures and caving of the caving stope 110 below the raise 102d can be performed in parallel. By the term “in parallel” is meant that the pre-conditioning measures may be carried out from the raise, whilst caving progresses in the stope underneath. Then pre-conditioning and caving may be performed at two different locations in the stope at the same time. Alternatively, the method steps may be alternated and performed at two different locations in a short period of time. This pre-conditioned zone 112 is characterized by artificial fractures inside the rock mass and/ or by a decreased strength of natural discontinuities inside the rock mass. Accordingly, the strength of the rock mass in the pre-conditioned zone 112 is reduced compared to its strength prior pre-conditioning. In FIG. 5b the competent rock mass formation 111 was pre-conditioned to facilitate its further caving.
[0311] FIG. 5c shows that caving has progressed into the previously competent rock mass formation 111. The zone of pre-conditioning 112 and the zone of fractured rock mass 108 overlap and are referred to as a zone of pre-conditioned and fractured rock mass 113.
[0312] Due to the pre-conditioning of specifically selected volumes of rock mass the rate of cave progression can be maintained and/ or increased in the competent zone, and caving is able to progress through the competent rock mass formation 111 without stalling.
[0313] FIG. 5d outlines that caving progressed completely through the competent rock mass formation 111. A zone of fractured rock mass 108 is situated above the stope 110 and caving continues to progress further.
[0314] The drawbell 100 and stope 110 illustrated in FIGS. 5b-5d are also provided with additional drawpoints arranged on different levels, however these are not shown in the figures.
[0315] Observations during development and operation inside raises in the present cave mining method according to the invention may be used for identification of competent rock mass formation requiring pre-conditioning. Moreover, raises enable to access critical rock mass formations to apply pre-conditioning measures selectively and on-demand. Due to the availability of raises pre-conditioning measures may be applied at the same time to drawbell development from said raise and/ or to caving of corresponding stope.
[0316] However, in another embodiment of the invention, pre-conditioning measures applied from machinery operating inside raises may be used to improve caving rate and thus the possible production rate from a stope.
[0317] FIGS. 6a-6e illustrate a vertical cross-section of one example of application of pre-breaking measures to advance a caving stope through a highly competent rock mass formation located in a specific area in the rock mass. FIG. 6a shows that caving of a stope 110 progresses below a highly competent rock mass formation 150. A zone of fractured rock mass 108 is located above the roof of the stope 110.
[0318] In FIG. 6b the roof of stope 110 reached the highly competent rock mass formation 150. The zone of fractured rock mass 108 above the roof of stope 110 has caved and fallen into the stope below the rock mass formation 150. Due to the strength of the highly competent rock mass formation 150, caving has stalled and the size of the void 109 has increased significantly.
[0319] FIG. 6c outlines the application of pre-breaking methods to advance the stope 110 through the highly competent rock mass formation 150. Pre-breaking methods may be performed by switching from caving to drilling and blasting for a limited time period by operating the machinery arranged inside the raise. Therefore, near horizontal drill holes 105 are drilled into the highly competent rock mass formation in a part of the stope from inside the raise by the machinery 120 (not shown in figure) operating inside the raise 102e. These drill holes are subsequently blasted slice by slice. FIG. 6d shows a situation, where some of the drill holes 105 have been blasted and the stope 110 has partially advanced through the highly competent rock mass formation 150. The size of the void 109 has decreased again. Finally, FIG. 6e shows that all drill holes 105 have been blasted and the stope 110 has been advanced through the highly competent rock mass formation 150 completely. Moreover, caving was re-initiated. A zone of fractured rock mass 108 is located above the roof of the stope 110 and caving progresses further. The drawbell 100 and stope 110 illustrated in FIGS. 6a-6e are also provided with additional drawpoints arranged on different levels, however these are not shown in the figures.
[0320] However, in another embodiment of the invention other pre-breaking measures than drilling and blasting may be applied.
[0321] FIGS. 7a-7d illustrate a vertical cross-section of one example of application of pre-conditioning measures to control the direction of cave progression near a weak rock mass formation.
[0322] FIG. 7a illustrates a stope 110, which is progresses upwards in vertical direction by means of caving. A zone of fractured rock mass 108 is prevailing above the roof of the stope 110. Moreover, a weak rock mass formation 114 is located above the roof of the stope 110. This weak rock mass formation 114 is characterized by a lower strength than its surrounding rock mass formations. Accordingly, caving progresses more easily in and along this weak rock mass formation 114. Thus, caving direction deviates from its planned direction as shown in the figure. The zone of fractured rock mass 108 already extends into the weak rock formation 114.
[0323] FIG. 7b shows the application of pre-conditioning measures to avoid significant deviation of the direction of cave progression. Therefore, near horizontal drill holes 105 are drilled from machinery operating inside the raise 102f. These drill holes 105 are subsequently used for application of pre-conditioning measures, for example hydraulic fracturing and/ or confined blasting. These pre-conditioning measures may be conducted from machinery 120 (not shown in this figure) situated on a platform 103 arranged inside the raise 102f.
[0324] FIG. 7c shows that pre-conditioning measures were applied and formed a zone of pre-conditioned rock mass 112. This zone of pre-conditioned rock mass 112 has a reduced strength as either artificial fractures were created, or natural discontinuities were weakened. The reduced rock mass strength in the pre-conditioned zone 112 facilitates caving in the planned direction.
[0325] FIG. 7d outlines that caving has progressed through the weak rock mass formation 114 without significant deviations into said weak rock mass formation. A suitable draw strategy is applied for drawing broken rock mass from the drawpoints. The draw strategy is critical for controlling direction of cave progression. The presence and arrangement of multiple drawpoints 106 located on several levels also facilitates the implementation of specific draw strategies.
[0326] FIGS. 8a-8c illustrate isometric views of different drawbell shapes. The integrated raise caving mining method according to the invention relies on the development of drawbells from raises.
[0327] Thereby, drawbell shapes may be chosen flexibly in order to meet requirements and prevailing mining environment.
[0328] FIG. 8a shows a drawbell 200a configured as an inverted pyramid such that the sidewalls of the drawbell have different inclinations. The drawbell 200a is developed from a vertical raise 202 and has a drawbell roof 201 which is inclined. The drawbell comprises a drawbell bottom and a drawbell roof which are joined by inclined sidewalls. The drawbell is configured with a drawbell roof area being larger than a bottom area of the drawbell, providing that the drawbell widens in a direction upwards. Thus the area of the horizontal cross-section of the drawbell increases in upwards direction. The inverted pyramid shape of the drawbell 200a may be adopted flexibly to local requirements, such as rock mass properties, stress situation, or ore flow considerations. For example, the outlined pyramid shaped drawbell 200a in FIG. 8a has a footprint of 68 m × 68 m, a height of 50 m, and a wall inclination of 60°. In one embodiment of the invention, the upper end of the drawbell, adjacent the undercut may be expanded only in upwards direction. In such a way the section of the draw bell just below the undercut obtains nearly vertical walls (not shown in the figures).
[0329] FIG. 8b shows a drawbell 200b designed like a trough with inclined sidewalls, which may have different inclinations, and a drawbell roof area being larger than a bottom area of the drawbell, providing that the drawbell widens in a direction upwards. The drawbell 200b is developed from a vertical raise 202 and the drawbell roof 201 is flat. The trough shape of the drawbell 200b may be adopted flexibly to local requirements, such as rock mass properties, stress situation, or ore flow considerations. For example, the outlined trough shaped drawbell 200 in FIG. 8b has a footprint of 70 m × 40 m, a height of 40 m, and a wall inclination of 70°.
[0330] FIG. 8c shows a drawbell 200c configured as an inverted cone, where the narrow cone end is directed downwards. The inverted cone has inclined sidewalls, which may have different inclinations. The drawbell 200c is developed from a vertical raise 202 and its drawbell roof 201 is flat. The cone shape of the drawbell 200c may be adopted flexibly to local requirements, such as rock mass properties, stress situation, or ore flow considerations. For example, the outlined cone shaped drawbell 200 in FIG. 8c has a footprint diameter of 60 m, a height of 50 m, and a wall inclination of 65°.
[0331] However, in other embodiments of the invention, the drawbells may be of other shape.
[0332] FIGS. 9a,9c illustrate isometric views of drawbell development from inclined raises and more than one raises, respectively. FIG. 9b illustrates a vertical cross-section of drawbell development from a raise.
[0333] FIG. 9a shows a drawbell 200d formed as an inverted pyramid. The drawbell 200d is developed from an inclined raise 202a and the drawbell roof 201 is inclined. The inclination of roof areas may be different for individual parts of the roof. For example, the raise inclination is 70° from the horizontal. The inclined raise 202a is positioned offset from the center of the drawbell roof 201. Alternatively, the inclined raise may be positioned in or near the center of the drawbell roof. In another embodiment of the invention, a vertical raise may also be positioned offset from the center of the drawbell roof. Alternatively, the vertical raise is positioned in or near the center of the drawbell roof.
[0334] FIG. 9b shows two drawbells 200e,200f. Drawpoints 206 are developed into drawbells 200e,200f. Drifts 204,207 are oriented in different directions and provide access to the drawpoints. The raise 202 is positioned inside the perimeter of the roof of drawbell 200f and is used for development of drawbell 200f by means of drilling and blasting performed from machinery operating inside the raise 202. Moreover, raise 202 is also used for development of drawbell 200e. Therefore, drill holes 205 are drilled from raise 202 above the drawbell roof 201 band subsequently blasted. Thus, drawbell 200e is developed by the raise located in rock mass outside the perimeter of the drawbell roof 201b.
[0335] FIG. 9c shows a drawbell 200g designed like a trough with inclined sidewalls. The drawbell 200g is developed, excavated, from two vertical raises 202 and the drawbell roof 201 is flat.FIG. 10 schematically illustrates a horizontal cross-section of the cave mining method according to the invention in an advanced progress of mining.
[0336] As caving progresses, the mined-out caving stopes may provide a stress shadow and, in specific parts of the rock mass, a favourable stress environment. Infrastructure for further drawbell and stope development, such as for example raises, drifts, or drawpoints may be positioned in these stress shadows, thereby protected from high stresses.
[0337] Stopes 310a,310b,310c,310d have been undercut and caving progresses. The stopes are filled with broken rock mass 301. In parallel, drawbells 300e,300f are developed from raises 302e,302f. The drawbells are shown as hatched lines, as drawbells are not visible in the shown cross-section, but rather located at predefined elevation below the shown cross-section. Thus, the hatched lines indicate the development and position of drawbells 300e,300f. Another raise 302g has also been developed for subsequent development of the corresponding drawbell. FIG. 10 further shows a stress shadow 320, thus a favorable stress environment formed near mined stopes 310a,310b,310c,310d. The actual distribution of the stress-shadow 320 and the favorable stress environment depend also on the prevailing rock mass conditions, primary stress magnitudes and directions as well as the mine layout and mining sequence. This stress shadow 320 protects raises 302e,302g from potentially high stresses, which may be present at the position of raises 302e,302g, in case no stress shadow would be provided. This circumstance concerns raise 302f, which is located at a position, where no stress shadow is present. However, raise 302f may be protected from high stresses by specifically designed de-stress excavations (not shown in FIG. 10), which have the function of providing a stress shadow, thus favorable stress environment for specific infrastructure. In summary, ongoing mining may provide stress shadows at specific locations. The delayed infrastructure development in the present cave mining method according to the invention allows use of these stress shadows for infrastructure protection strategically. Thereby, infrastructure stability is improved, which in turn affects the safety, economics, and extraction of the deposit positively.
[0338] FIGS. 11a-11e schematically illustrate isometric views of one example of an implementation of the integrated raise caving mining method according to the invention. The figures show one example of the integration of the individual steps of the method as described herein. The development of drawbells from raises and development of infrastructure, such as drifts and drawpoints are shown. Moreover, undercutting, cave initiation, and cave progression, thereby mining of caving stopes are outlined. It should be noted that the mining layout of the example of the integrated raise caving mining method as illustrated in the figures is very flexible.
[0339] Finally, the FIGS. 11a-11e illustrate an example of a mining sequence of the integrated raise caving mining method.
[0340] FIG. 11a provides an isometric view of the initial stages of the integrated raise caving mining method and shows the development of the infrastructure required for the first drawbells as well as the development of the first drawbell. Infrastructure comprises drifts 407, drawpoints 406 and raises 402a,402b. Drifts 407 have been developed at a production level 431 and at a raise level 441. It should be noted that the terms “production level” and “draw level” are synonyms. Afterwards raises 402a,402b have been developed between the production level 431 and the raise level 441. Thus, the raises 402a,402b are developed to extend over only a part of the stope height above the drawbell. Raises may be developed by means of raise boring method or by means of other methods. The distance between the production level 431 and the raise level 441 is influenced amongst others by the final drawbell height, the prevailing rock mass and stress conditions and the applied mining sequence. Raise 402a is used for the development of the first drawbell 400a by means of drilling and charging. At least a part of an undercut is created through gradually expanding the drawball in upwards direction by excavation, and increasing the roof area of the drawbell. Therefore, machinery 120 suitable for drilling and blasting (not shown in figure) operating inside the raise is used. The drawbell 400a has not been developed to the final size and shape yet. The latter circumstance implies that the roof area of the flat drawbell roof 401a is still smaller than the final drawbell roof size. Accordingly, caving has not been initiated yet. After every blast, blasted rock mass falls from the drawbell roof 401a into the drawbell 400a. The blasted rock mass is loaded at drawpoints 406 out of the drawbell 400a. Thereby, a void is formed below the drawbell roof 401a. This void is required for subsequent blasts, to accommodate the swell of the blasted rock mass. Due to the inverted-pyramid shape of the drawbell 400a, blasted material inside the drawbell flows to the bottom of the drawbell, where it is loaded at drawpoints 406. The number, size, and spacing of drawpoints 406 depends on prevailing rock mass and stress conditions as well as on ore flow aspects, for example the fragmentation of the broken rock mass inside the drawbell, or the applied draw strategy. However, in another embodiment of the invention, the drawbell may also be of other shape, for example a trough shape, or inverse cone shape. After loading material at drawpoints 406, the material is transported in drifts 407 to the ore handling system, which may be located inside or outside the active mining area (the ore handling system is not shown in the Figure). FIG. 11a shows besides development of the first drawbell 400a the infrastructure required for the development of the second drawbell.
[0341] FIG. 11b provides an isometric view of one example of a more advanced stage of drawbell and infrastructure development of the method according to the invention, than FIG. 11a. The drawbell 400a has been developed to its predefined height. Thus, the roof 401a of the drawbell reached its final size. Thus, raise 402a is not required for further drilling and charging activities of the drawbell 400a. However, the raise 402a may still be used for monitoring purposes, for example the drawbell roof 401a, or the broken rock mass inside the drawbell 400a. Moreover, the raise 402a may still be used for additional pre-conditioning methods and/ or pre-breaking methods in specific locations in the rock mass above the drawbell roof 401a on demand. The size of the drawbell roof 401a is still too small to initiate caving. To increase the size of the undercut and to initiate caving subsequently, drawbell 400b is under development. Therefore, drilling and blasting in raise 402b is used. Blasted rock mass from drawbell development is drawn from drawbell 400b at drawpoints 406 situated at the production level 431. The drawbell 400b has not reached its final size and shape yet.
[0342] Moreover, FIG. 11b shows that a second production level 432, which is located at a predetermined distance above the first draw level 431, has been developed. Drifts 407 were developed. Some of these drifts are located near the drawbell 400a. In a later stage, further drawpoints will be developed from said drifts 407 into the drawbell 400a.
[0343] FIG. 11b outlines the further extension of the method according to the invention. Drifts 407 have been developed at a second raise level 442 and drifts 407 have been extended or newly developed at draw level 431. Additionally, a third raise 402c has been developed between drifts 407 at the draw level 431 and drifts 407 at the raise level 442. The raise level 442 is located at a higher elevation than raise level 441. The reason, therefore, is that a zone of competent rock mass 411 is present near raise 402c and between raise levels 441 and 442. This zone of competent rock mass requires pre-conditioning. The pre-conditioning measures may be conducted from machinery 120 (not shown in figure) operating inside the raise 402c before drawbell development from raise 402c starts. However, in another embodiment of the invention, said pre-conditioning measures and drawbell development may be conducted from the same raise in parallel. This means that these method steps may be performed at the same time. Alternatively, pre-conditioning may be conducted during cave progression below the competent rock mass zone. FIG. 11b shows further that pre-conditioning measures can be applied in the competent zone selectively, because the raise 402c intersects the competent zone.
[0344] The zone of competent rock mass 411 does not extend in the area above raise level 441. There was no requirement for pre-conditioning in the area above raise level 441. For this reason, raise level 441 is located closer to the draw level 431, which is used for drawbell development, so that costs for infrastructure development can be reduced. Consequently, the position of raise levels and infrastructure in the integrated raise caving mining method can be adapted to local conditions.
[0345] FIG. 11c provides an isometric view of one example of the method according to the invention of a stage, where caving has been initiated through undercutting. Further infrastructure was developed for additional drawbells and caving stopes. Drawbell 400b is completely developed. Accordingly, drawbell roofs 401a,401b of drawbells 400a,400b have been joined and connected. The connected roof area of drawbells 400a,400b exceeded the critical unsupported area required for cave initiation. Thus, caving has been initiated and progresses upwards. As caving progresses upwards the volume of the caving stopes 410a,410b increases. As caving stopes 410a,410b are adjacent to each other they form a larger coherent caving stope. Caved rock mass in stopes 410a,410b is drawn through drawbells 400a,400b at drawpoints 406. Consequently, a void forms on top of the caved rock mass in stopes 410a,410b, which allows further detachment of rock mass from the cave back, as loading of the broken rock mass is performed through drawpoints 406, thereby caving progresses. Caving in stopes 410a,410b progressed above raise level 441. Accordingly, there are no further raises above the caving stopes 410a,410b available for monitoring, pre-conditioning or pre-breaking measures.
[0346] Drawpoints 406 are located at the production levels 431,432. Drawpoints situated at production level 432 located above level 431 were developed delayed. This means that drawpoints 406 at the production level 432 were developed into the drawbells 400a,400b after drawbell development was completed and after caving was initiated. This delayed drawpoint development enables to protect drawpoints from high stresses during drawbell development and associated undercutting as well as to position the drawpoints 406 according local rock mass conditions and ore flow considerations. Moreover, drawpoints 406 were developed into drawbells 400a,400b in different directions. Overall, the development of drawpoints 406 on more than one draw levels provides the possibility to improve the drawpoints arrangement from an ore flow point of view.
[0347] FIG. 11c outlines that infrastructure on raise levels 441,442 and production levels 431,432 have been extended to prepare further parts of the ore body for extraction. Drawbell 400c is fully developed. The drawbell roof 401c is connected to the caving stope 410b. Consequently, the undercut area has been increased and a zone of fractured rock mass is just about to develop in the rock mass 10 above the drawbell roof 401c. However, caving has not progressed yet above drawbell roof 401c. In addition to drawbell 400c, drawbell 400e is under development. Therefore, a raise 402e has been developed between the production level 431 and the raise level 441. Said raise 402e may benefit from a stress shadow. Thus, a favorable stress environment is provided by caving stopes 410a, 410b. The extent of this stress shadow and the benefit of raise 402e of the stress shadow depend amongst others on the prevailing stress and rock mass conditions and on the position of raise 402e in respect to stopes 410a, 410b.
[0348] FIG. 11c highlights that the infrastructure, required for increasing the production area, may be developed shortly before production commences in respective areas. Moreover, the mining layout of the integrated raise caving mining method, according to the invention, allows parallel infrastructure development and production ramp-up.
[0349] FIG. 11d provides an isometric view of one example of a stage of the method according to the invention, where several drawbells are fully developed and where caving progressed in several stopes. Drawbells 400a,400b,400c,400e are fully developed and caving in stopes 410a,410b,410c progressed. So far, caving has not progressed above drawbell 400e. However, the drawbell roof 401e of drawbell 400e has already been connected to the stope 410a. Thereby the size of the undercut area has increased further. Moreover, further infrastructure has been developed. Raise 402d is developed between raise level 442 and the production level 431. Raise 402d intersects the strong competent zone and enables the planned application of pre-conditioning measures in the competent zone 411. Additionally, new drifts 407 have been developed on production levels 431,432.
[0350] FIG. 11e provides an isometric view of one example of continuing infrastructure development and cave progression in the method according to the invention. The volume of caving stopes 410a,410b,410c,410e has increased and development of drawbell 400d started.
[0351] The example of the invention as shown in FIG. 11e, further comprises infrastructure and drawbells for two additional stopes arranged to the left of stope 410e, but to avoid further complexity of FIG. 11e those features are not shown.
[0352] Overall, FIGS. 11a,11b,11c,11d,11e illustrate the principle steps of the integrated raise caving mining method according to the invention. The actual mine layout and mining sequence depend on several parameters, such as the ore body geometry, the ore body size, the grade distribution, the prevailing rock mass properties, the prevailing stress situation, and the production. Moreover, the mine layout and mining sequence may be adapted flexibly and on short notice to encountered conditions and circumstances.
[0353] FIGS. 12a-12c schematically illustrate vertical cross-sections of examples of the method according to the invention. FIGS. 12a-c show the draw zones of individual drawpoints and the development of an interactive draw zone.
[0354] FIG. 12a provides a vertical cross-section of one example of a drawbell 500 and shows the effect of drawing drawpoints in isolation. Drawpoints 506 are developed into the drawbell 500. Access tunnels 507 and 508 are used as an access to the drawpoints 506. Drawing broken rock mass from drawpoints 506 maintains the flow of broken rock mass inside the drawbell towards the drawpoints 506. However, every drawpoint 506 maintains the flow of broken rock mass only in a certain area. This area is commonly referred to as isolated draw zone 501. Drawpoints 506 are drawn in isolation, which means that one drawpoint is drawn at a time, and drawing from a neighboring drawpoint commences only after a considerable time period. Thus, the draw is considered to be not uniform, both temporarily and spatially. Drawpoints 506 are arranged such that their isolated draw zones 501 do not touch or intersect each other. Correspondingly, a zone of relatively stationary material 504 remains between neighboring draw zones 501. This zone of relatively stationary material 504 is characterized by broken rock mass, which is either not flowing at all or which is flowing at a very slow rate compared to the material inside the isolated draw zone 501. The size and shape of the isolated draw zone 501 depend on several parameters, which comprise amongst others the fragmentation of the broken rock mass, the size and shape of the drawpoint and the prevailing stress situation inside the broken rock mass.
[0355] However, in another embodiment of the invention drawpoints may be arranged such that their isolated draw zones overlap at least in some areas. Thus, there is smaller zone of relatively stationary material between neighboring isolated draw zones.
[0356] FIG. 12b shows a vertical cross-section of one example of a drawbell 500 with four drawpoints 506 and illustrates the effects of drawing drawpoints interactively. Drawpoints are accessed from access tunnels 507. Isolated draw zones 501 develop above corresponding drawpoints 506 due to draw of rock mass. However, in contrast to FIG. 12a drawing from drawpoints 506 is carried out in FIG. 12b interactively. This interactive draw is realized by drawing broken rock mass from neighboring drawpoints at the same time or within a short time interval. As drawpoints 506 are drawn interactively, isolated draw zones of individual drawpoints start to interact. Consequently, broken rock mass between neighboring isolated draw zones 501 starts to move as well. Therefore, an interactive draw zone 502 develops near isolated draw zones 501. The size and shape of this interactive draw zone 502 depend on several parameters, for example the applied draw strategy, the arrangement of drawpoints, or the fragmentation of the broken rock mass. A uniform draw both temporarily and spatially from drawpoints is pursued to enlarge the interaction in the interactive draw zone. Overall, the interactive draw zone 502 effect is that the flow of broken rock mass is maintained in a larger volume of broken rock mass compared to the volume of isolated draw zone 501. Moreover, raises 102 (not shown in this figure) used for development of the drawbell may be used for monitoring the fragmentation, the lowering of broken rock mass inside a caving stope, the cave and/or cave back. This monitoring information/ data may then be used for draw control and eventually to adapt the draw strategy such that a better interactive draw can be achieved. A zone of relatively stationary material 504 may still be present, especially near the sidewalls of the drawbell.
[0357] FIG. 12c provides a vertical cross-section of one example of two drawbells 500a,500b and illustrates the effect of drawing broken rock mass from neighboring drawbells interactively. Drawpoints 506 developed from access tunnels 507 are used for drawing broken rock mass from drawbells. Drawpoints 506 of individual drawbells 500a,500b are drawn interactively. Thereby, the isolated draw zones 501 of corresponding drawpoints form an interactive draw zone 502 in every drawbell 500a,500b. Interactive draw zones 502 of drawbell 500a and 500b do not intersect or touch each other. Due to the draw of broken rock mass from neighboring drawbells 500a,500b in the same time period, interactive draw zones 502 start to interact, thereby forming an interactive draw zone across drawbells 503. Moreover, the inclined sidewalls of drawbells further assist latter interaction. Thus, the interactive draw in each drawbell results in larger drawbell interactive zones, which interact across the drawbells. The size and shape of this interactive draw zone across drawbells 503 depends on several parameters, for example the applied draw strategy, the size and shape of neighboring drawbells, or the arrangement of drawpoints. Due to the development of the interactive draw zone across drawbells 503, a uniform mass flow of broken rock mass is implemented across the drawbells. A zone of relatively stationary material 504 may still be present, especially near the sidewalls of the drawbell.
[0358] However, in another embodiment of the invention, drawbells may be arranged such that the interactive draw zones from drawbells overlap at least in some areas.
[0359] FIG. 13a schematically illustrates a horizontal cross-section of an example of the method according to the invention and shows the arrangement of isolated and interactive draw zones.
[0360] FIG. 13b schematically illustrates a vertical section along line A-A of FIG. 13a.
[0361] FIG. 13a provides a horizontal cross-section of a coherent caving stope located above neighboring drawbells 500a, 500b. The drawbells are indicated by dashed lines, whereas lines 511 indicate the bottom of the drawbells and lines 512 indicate the top of the drawbells. The drawbells 500a,500b have a trough shape and the drawpoints are developed into the drawbells. The position of the drawpoint centers are shown by a cross-symbol 510. All drawpoints in FIG. 13a are drawn interactively. Forthis reason, an interactive draw zone 502 is created surrounding the isolated draw zones 501 of each drawpoint. Moreover, an interactive draw zone 503 across drawbells is established, because drawpoints from the neighboring drawbells are drawn in the same time period. The drawpoints in FIG. 13a are arranged in a square layout 520.
[0362] FIG. 13b shows the drawbells 500a,500b and the arrangement of isolated and interactive draw zones as illustrated in FIG. 13a.
[0363] However, in another embodiment of the invention, the drawpoints may be arranged in other layouts, for example a staggered or rectangular layout. The actual arrangement of drawpoints depends on local circumstances, for example the fragmentation of rock mass, the size and shape of drawpoints, the size and shape of drawbells, or the applied draw strategy.
[0364] Draw strategy is considered important for controlling the cave progression and direction, because it governs the development of the void below the zone of fractured rock mass and the broken rock mass inside the stope. Moreover, information gained from monitoring the cave back and broken rock mass pile from raises may be used to adopt the draw strategy appropriately, flexibly, and on short notice.
[0365] FIG. 14 schematically illustrates an integrated raise caving mining infrastructure 902 comprising an automatic or semi-automatic control system 901 electrically coupled to a control circuitry 900. The integrated raise caving mining infrastructure 902 is configured for mining deposits in a rock mass 10 and comprises at least one raise 102 developed in a direction upwardly from a drift 115 located in the rock mass 10. A drawbell 100 is developed in the rock mass 10, wherein at least a portion of the drawbell is joined to the at least one raise 102. The integrated raise caving mining infrastructure 902 comprises an undercut UC, wherein at least a portion of the undercut UC is formed as a drawbell roof of the drawbell 100, and wherein said portion has been created by gradually expanding the drawbell in upward direction by excavation. The integrated raise caving mining infrastructure 902 further comprises at least two drawpoints 106 joined to the drawbell 100, wherein the drawpoints 106 are joined to drifts arranged on different levels, and comprises a transport device 904 configured to progressively draw fragmented rock from the drawbell 100.
[0366] Alternatively, a caving stope (not shown) is located above the drawbell 100. The drawbell of the integrated raise caving mining infrastructure 902 may have other shapes than that shown in the figure.
[0367] The integrated raise caving mining infrastructure 902 may further comprise a machinery 910 that may comprise a drilling and/or charging device (not shown) configured for developing the raise 102 in the rock mass 10. The machinery 910 is configured for developing the drawbell 100 in the rock mass 10, wherein at least a portion of the drawbell is excavated from the raise by drilling,and/ or charging by means of the machinery 910, thereby initiating caving through undercutting. The machinery 910 is configured for developing the drawbell by gradually expanding the drawbell in upwards direction by excavation and for developing the at least two drawpoints 106 into the drawbell 100, wherein the drawpoints 106 are developed from drifts arranged on different levels. The machinery 910 may comprise the transport device 904 configured for transporting fragmented rock from the drawbell 100 through the drawpoints 106.
[0368] The machinery 910 may be configured to be operated by the automatic or semi-automatic control system 901 in remote control mode and/or in automatic control mode and/or in semi-automatic control mode.
[0369] The machinery 910 may be configured for drilling and/or charging the rock mass from inside the raise 102. The machinery 910 may comprise a drilling bore and/or charging equipment configured for initiating said caving. The machinery 910 may comprise pre-conditioning equipment. The machinery 910 may comprise that the drilling and/or charging device is arranged on a movable platform, which is movable within the raise 102 for reaching a position for operation of the drilling and/or charging device. The machinery 910 may comprise that the platform is configured with a modular design. The machinery 910 may comprise that the platform is configured to be stored by moving it aside from the top of the raise. The machinery 910 and/or equipment arranged on the platform may be configured with a modular design. The machinery 910 may be configured for installing rock support and/or rock reinforcement from inside the raise 102, such as rock bolts, mesh, shotcrete, cable bolts. The machinery 910 may be configured for hydrofracturing the rock mass from inside the raise 102. The machinery 910 may be configured for performing directional drilling. The machinery 910 may be configured for drilling curved boreholes by directional drilling. The machinery 910 may be configured for blast initiation of the charged boreholes. The machinery 910 may be configured for blast initiation from inside the raise 102. The machinery 910 may be configured for blast initiation by wired detonators and/ or remote-controlled detonators and/ or non-electric detonators and/ or wireless detonators. The machinery 910 may be configured for transporting fragmented rock 101 continuous draw machinery with conveyors and/or trucks and/ or loaders.The machinery 910 may be configured to be operated by remote control. The machinery 910 may be configured for semiautomation or full automation. The machinery 910 may be configured to be operated manually.
[0370] The integrated raise caving mining infrastructure 902 may further comprise a monitoring system 920 configured for monitoring an integrated raise caving mining infrastructure 902 configured for mining deposits in rock mass.
[0371] The monitoring system 920 comprises monitoring means configured for monitoring development of at least one raise 102, 102a-f, 202, 302a-g, 402a-e developed in the rock mass 10. The monitoring system 920 comprises monitoring means configured for monitoring development of a drawbell 100, 100a-c, 200a-g, 300a-f, 400a-e in the rock mass 10, wherein at least a portion of the drawbell is joined to the at least one raise 102, 102a-f, 202, 302a-g, 402a-e. The monitoring system 920 comprises monitoring means configured for monitoring development of an undercut (UC) being configured to initiate caving of rock mass located above the undercut, wherein said portion has been created by gradually expanding the drawbell in upward direction by excavation. The monitoring system 920 comprises monitoring means configured for monitoring initiation of caving. The monitoring system 920 comprises monitoring means configured for monitoring development of at least two drawpoints 106, 206, 406 wherein the drawpoints 106 are joined to drifts 115,207,407 arranged on different levels. The monitoring system 920 may be configured for monitoring of a transport device 904 configured to progressively draw fragmented rock (101) from the drawbell. The monitoring system 920 may be configured for monitoring cave progression and/ or direction of cave progression.The monitoring system 920 may be configured for monitoring of caved rock mass by using a remote controlled monitoring device arranged inside the raise. The monitoring system 920 may be configured for remotely monitoring of the caving stope and/ or the cave back (119) and/ or the caved rock masses (101). The monitoring system 920 may be configured for monitoring an advancing fracture and loosening zone located above the cave back. The monitoring system 920 may be configured for monitoring seismicity and/ or stress in the deposit wherein the integrated raise caving mining infrastructure 902 is located. The monitoring system 920 may be configured for collecting monitoring data, analysing monitoring data, storing of monitoring data, and/or transmitting monitoring data via wireless communication means to an automatic or semi-automatic control system 901 of an integrated cave mining infrastructure 902.
[0372] The monitoring system 920 comprises amongst others a plurality of monitoring means, a central monitoring unit, data collection units, data storage means, communication devices and/or data analysis tools. The monitoring system 920 may be configured to communicate with the automatic or semi-automatic control system 901 and to transmit data and information generated by the monitoring system to the automatic or semi-automatic control system 901. The monitoring means comprises for example seismic monitoring system, time domain reflectometry technology, open bore holes, cavity scanners, sensors, marker or geophones.
[0373] FIG. 15 illustrates a flowchart showing an example of an integrated raise caving mining method. The method comprises a first step 701 starting the method. A second step 702 comprises the performance of the exemplary method. A third step 703 comprises stopping the method. The second step 702 may comprise developing at least one raise in the rock mass, developing a drawbell in the rock mass, wherein at least a portion of the drawbell is excavated from the at least one raise by drilling, charging and blasting by operating a machinery arranged inside the at least one raise, initiating caving through undercutting, wherein at least a part of an undercut is created by gradually expanding the drawbell in upwards direction by excavation, developing at least two drawpoints into the drawbell, wherein the drawpoints are developed from drifts arranged on different levels, progressively drawing fragmented rock from the at least one drawbell through the drawpoints.
[0374] FIG. 16 illustrates a flowchart showing a further example of an integrated raise caving mining method. The indicated method steps in the example may be performed in any order.
[0375] The method comprises a first step 801 starting the method. A second step 802 comprises developing at least one raise in the rock mass. A third step 803 comprises developing a drawbell in the rock mass, wherein at least a portion of the drawbell is excavated from the at least one raise by drilling and charging by operating a machinery arranged inside the at least one raise and thereafter blasting. A fourth step 804 comprises excavation for developing a roof area of the drawbell being larger than a bottom area of the drawbell. A fifth step 805 comprises initiating caving through undercutting, wherein at least a part of an undercut is created by gradually expanding the drawbell in upwards direction by excavation. A sixth step 806 comprises developing at least two drawpoints into the drawbell, wherein the drawpoints are developed from drifts arranged on different levels. A seventh step 807 comprises progressively drawing fragmented rock from the at least one drawbell through the drawpoints. An eight step 808 comprises initiating caving when the undercut area exceeds a critical area. A ninth step 809 comprises caving the rock mass located above the drawbell, thereby forming a caving stope. A tenth step 810 may comprise pre-conditioning of rock mass located above the drawbell roof by operating a machinery arranged inside the at least one raise. An eleventh step 811 may comprise pre-breaking of rock mass located above the drawbell roof by operating a machinery arranged inside the at least one raise. A twelfth step 812 may comprise a switching from caving to drill and blast for a specific area in the stope. A thirteens step 813 comprises stopping the method.
[0376] FIG. 17 illustrates a control circuitry 900 (such as a central control processor or other computer device) adapted to operate an automatic or semi-automatic control system 901 of an integrated cave mining infrastructure 902, which automatic or semi-automatic control system 901 is configured to perform any exemplary integrated raise caving mining method herein described. The control circuitry 900 is configured to control any exemplary method or methods disclosed herein. The control circuitry 900 comprises a data medium, configured for storing a data program P. The data program P is configured (programmed) for controlling the automatic or semi-automatic control system 901 and/or for controlling the machinery and/or for communicating with the monitoring system 920 in FIG. 14. The data medium comprises a program code readable by the control circuitry 900 for performing any of the exemplary methods herein described, when the data medium is run on the control circuitry 900.
[0377] The control circuitry 900 is electrically coupled to a machinery (not shown) comprising a drilling and/or charging device (not shown). The control circuitry 900 is further configured to communicate with the monitoring system 920 via wired and/ or wireless communication system to transmit and/or receive monitoring data. The control circuitry 900 is configured to provide that the automatic or semi-automatic control system 901 and/or machinery each performs the method of developing at least one raise in the rock mass, developing a drawbell in the rock mass, wherein at least a portion of the drawbell is excavated from the at least one raise by drilling, charging and blasting by operating a machinery arranged inside the at least one raise, initiating caving through undercutting, wherein at least a part of an undercut is created by gradually expanding the drawbell in upwards direction by excavation, developing at least two drawpoints into the drawbell, wherein the drawpoints are developed from drifts arranged on different levels, progressively drawing fragmented rock from the at least one drawbell through the drawpoints.
[0378] The control circuitry 900 may thus also be configured for manoeuvring a transport device, such as a remote-controlled loading device, or continuous draw machinery with conveyors in a drift (not shown). The control circuitry 900 comprises a computer and a non-volatile memory NVM 1320, which is a computer memory that can retain stored information even when the computer is not powered.
[0379] The control circuitry 900 further comprises a processing unit 1310 and a read/write memory 1350. The NVM 1320 comprises a first memory unit 1330. A computer program (which can be of any type suitable for any operational data) is stored in the first memory unit 1330 for controlling the functionality of the control circuitry 900. Furthermore, the control circuitry 900 comprises a bus controller (not shown), a serial communication unit (not shown) providing a physical interface, through which information transfers separately in two directions.
[0380] The control circuitry 900 may comprise any suitable type of I/O module (not shown) providing input/output signal transfer, an A/D converter (not shown) for converting continuously varying signals from a sensor arrangement (not shown) of the control circuitry 900 configured to determine actual status of the machinery and/or the automatic or semi-automatic control system 901. The control circuitry 900 is configured to, from received control signals, determine the positions of the machinery regarding drilling and operation of the explosive material charging into binary code suitable for the computer, and from other operational data.
[0381] The control circuitry 900 also comprises an input/output unit (not shown) for adaptation to time and date. The control circuitry 900 comprises an event counter (not shown) for counting the number of event multiples that occur from independent events in operation of the machinery and/or the automatic or semi-automatic control system 901.
[0382] Furthermore, the control circuitry 900 includes interrupt units (not shown) associated with the computer for providing a multi-tasking performance and real time computing. The NVM 1320 also includes a second memory unit 1340 for external sensor check of the sensor arrangement.
[0383] A data medium for storing a program P may comprise program routines for automatically adapting the operation of the machinery and/or the automatic or semi-automatic control system 901 in accordance with operational data regarding e.g. the actual status of gradually expanding the drawbell in upward direction by excavation.
[0384] The data medium for storing the program P comprises a program code stored on a medium, which is readable on the computer, for causing the control circuitry 900 to perform the method and/or method steps described herein.
[0385] The program P further may be stored in a separate memory 1360 and/or in the read/write memory 1350. The program P, in this embodiment, is stored in executable or compressed data format.
[0386] It is to be understood that when the processing unit 1310 is described to execute a specific function that involves that the processing unit 1310 may execute a certain part of the program stored in the separate memory 1360 or a certain part of the program stored in the read/write memory 1350.
[0387] The processing unit 1310 is associated with a data port 1399 adapted for electrical data signal communication via a first data bus 1315 provided to be coupled to the machinery and/or the automatic or semi-automatic control system 901 for performing any of the exemplary method steps herein described.
[0388] The non-volatile memory NVM 1320 is adapted for communication with the processing unit 1310 via a second data bus 1312. The separate memory 1360 is adapted for communication with the processing unit 610 via a third data bus 1311. The read/write memory 1350 is adapted to communicate with the processing unit 1310 via a fourth data bus 1314. After that the received data is temporary stored, the processing unit 1310 will be ready to execute the program code, according to the above-mentioned method.
[0389] Preferably, signals (received by the data port 1399) comprise information about operational status of the machinery and/or the automatic or semi-automatic control system 901.
[0390] Information and data may be manually fed, by an operator, to the control circuitry 900 via a suitable communication device, such as a computer display or a touchscreen. The exemplary methods herein described may also be partially executed by the control circuitry 900 by means of the processing unit 1310, which processing unit 1310 runs the program P being stored in the separate memory 1360 or the read/write memory 1350. When the control circuitry 900 runs the program P, anyone of the exemplary methods disclosed herein will be executed.
[0391] The foregoing description of the preferred embodiments is provided for illustrative and descriptive purposes. It is not intended to be exhaustive, or to limit the embodiments to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described to best explain the principles and practical applications, and hence make it possible for specialists to understand the invention for various embodiments and with various modifications that are applicable to its intended use.
[0392] The present invention is of course not in any way restricted to the examples described above, but many possibilities to modifications, or combinations of the described embodiments thereof should be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention as defined in the appended claims.
