A housing mount assembly for supporting a roller cutter is described. The housing mount assembly comprises a housing mount defining an outer surface for attaching to a housing and a profiled inner surface extending away from the outer surface, the profiled inner surface defining a channel extending in a longitudinal direction, and a seat support block extending away from the outer surface and defining a first seat support surface transverse to the channel, and a second seat support surface transverse to the first seat support surface. The housing mount assembly further comprises a removable seat mounted on the seat support surfaces and defining two transverse roller cutter shaft support surfaces whereby the removable seat and the seat support block together provide support for a roller cutter shaft.

Earth-boring rotary drill bits include heel portions exhibiting reduced aggressiveness. Earth-boring rotary drill bits may comprise a bit body and a plurality of roller cones coupled to the bit body. Each roller cone comprises a plurality of rows of cutting elements, and a continuous disk heel located further from an axis of rotation of the roller cone than the at least one row of cutting elements, the continuous disk heel exhibiting a reduced amount of aggressiveness compared to the at least one row of cutting elements.

Earth-boring rotary drill bits include heel portions exhibiting reduced aggressiveness. Earth-boring rotary drill bits may comprise a bit body and a plurality of roller cones coupled to the bit body. Each roller cone comprises a plurality of rows of cutting elements, and a continuous disk heel located further from an axis of rotation of the roller cone than the at least one row of cutting elements, the continuous disk heel exhibiting a reduced amount of aggressiveness compared to the at least one row of cutting elements.

According to a first aspect of the invention there is provided a cutter head arrangement comprising a cutter head portion including a (substantially cylindrical) cutter head side wall to define a chamber (or cavity) surrounded by the cutter head side wall. A substantially circular rim portion extends from (a distal end of) the cutter head side wall, the rim portion defining a working, contact face of the cutter head portion. A recessed wall portion extends away from the rim portion inwardly into the chamber so as to be surrounded by the cutter head side wall, with the rim portion and/or the recessed wall portion being fitted with a plurality of cutter elements, to enable the cutter head portion to blind bore a pilot hole in use. The recessed wall portion that extends away from the rim portion inwardly into the chamber is a substantially conical body so as to define a conical recess (proximate a central region of the cutter head portion, at a distal end of the cutter head portion). The conical body accordingly defines an inwardly extending apex that terminate substantially in line with a central axis of the cutter head portion.

According to a first aspect of the invention there is provided a cutter head arrangement comprising a cutter head portion including a (substantially cylindrical) cutter head side wall to define a chamber (or cavity) surrounded by the cutter head side wall. A substantially circular rim portion extends from (a distal end of) the cutter head side wall, the rim portion defining a working, contact face of the cutter head portion. A recessed wall portion extends away from the rim portion inwardly into the chamber so as to be surrounded by the cutter head side wall, with the rim portion and/or the recessed wall portion being fitted with a plurality of cutter elements, to enable the cutter head portion to blind bore a pilot hole in use. The recessed wall portion that extends away from the rim portion inwardly into the chamber is a substantially conical body so as to define a conical recess (proximate a central region of the cutter head portion, at a distal end of the cutter head portion). The conical body accordingly defines an inwardly extending apex that terminate substantially in line with a central axis of the cutter head portion.

A cutting apparatus includes a support structure and first and second cutting assemblies. Each cutting assembly includes a rotatable cutting head and a mounting assembly for movably attaching the cutting head to the support structure. The cutting head is movable about a first pivot axis of the mounting assembly in a sideways direction relative to the support structure, and about a second pivot axis in an upwards-downwards direction. Each cutting head includes a plurality of cutting units, which each have a rotatable shaft and a cutter mounted thereon. The cutter includes a disc body and a plurality of buttons mounted in a radially peripheral portion of the disc body. At least some of the buttons have a central longitudinal axis that subtends an angle α to a reference axis, which extends perpendicularly outwards from an axis of the shaft, the angle α being ≥to 20° and ≤to 34°.

A disc cutter for a cutting unit used in a tunnel boring machine and a method of producing the same. The disc cutter includes an annular disc body made of a metal alloy or metal matrix composite having a first side, a second side arranged substantially opposite to the first side and a radially peripheral part. At least one metal alloy, metal matrix composite or cemented carbide cutting part is mounted in and substantially encircling the radially peripheral part of the disc body, which protrudes outwardly therefrom to engage with the rock during the mining operation. The at least one cutting part is made from a material having a higher wear resistance than the material used for the disc body. A metallic interlayer is disposed between at the least one disc body and the at least one cutting part, the elements of which form the diffusion bonds.

A disc cutter for a cutting unit used in an undercutting operation and a method of producing the same. The disc cutter including an annular disc body made of a metal alloy or metal matrix composite having a first side, a second side arranged substantially opposite to the first side and a radially peripheral part. At least one metal alloy, metal matrix composite or cemented carbide cutting part is mounted in and substantially encircling the radially peripheral part of the disc body which protrudes outwardly therefrom to engage with the rock during the mining operation. The at least one cutting part is made from a material having a higher wear resistance than the material used for the disc body, wherein the disc body and the cutting part are joined by diffusion bonds.

A disc cutter for a cutting unit used in an undercutting operation and a method of producing the same. The disc cutter including an annular disc body made of a metal alloy or metal matrix composite having a first side, a second side arranged substantially opposite to the first side and a radially peripheral part. At least one metal alloy, metal matrix composite or cemented carbide cutting part is mounted in and substantially encircling the radially peripheral part of the disc body which protrudes outwardly therefrom to engage with the rock during the mining operation. The at least one cutting part is made from a material having a higher wear resistance than the material used for the disc body, wherein the disc body and the cutting part are joined by diffusion bonds.

A hybrid bit includes a fixed cutting structure and a rolling cutting structure. The fixed cutting structure includes a plurality of fixed cutting elements. The rolling cutting structure is coupled to the fixed cutting structure and includes a journal bore extending through the rolling cutting structure from a leading face to a trailing face, and a radially outer surface. The rolling cutting structure also includes a plurality of cutting elements extending from the radially outer surface of the rolling cutting structure.