A raise boring head for rotary boring in rock having a main body mountable at a drive shaft in which a mount face provides a supporting surface for a plurality of saddles that mount, in turn, respective roller cutters. At least one guide block is attached to the main body to project upwardly from the mount face and includes at least one guide face to facilitate the transport of cut material away from the mount face.

A pump down ring is utilized in a downhole tool for use in a subterranean well. The pump down ring is positioned around the outer surface of a sleeve and is slidably disposed thereon. The pump down ring slidably engages the sleeve so as to have a radially-relaxed position and an expanded position where the pump down ring is expanded radially outward from the radially-relaxed position. Accordingly, the pump down ring can be placed in its expanded position to facilitate placement of the downhole tool in a wellbore by use of fluid pressure and can be placed in its radially-relaxed position to facilitate removal of the downhole tool from the wellbore.

A method for removing material with a bit includes rotating a bit in a first direction, changing the rotational direction and rotating the bit in an opposing second direction. Rotation of the bit in the first direction and rotation of the bit in the second direction both remove material.

A device for advancing a cavity in underground mining, including a rotary drive, an axial shaft that is rotatable together with the rotary drive about a longitudinal axis, exactly one extraction drum that is rotatable about an drum rotational axis, and a connecting arrangement which is connected to the axial shaft and which supports the extraction drum, the connecting arrangement being configured in such a way that the drum rotational axis and the longitudinal axis lie in a plane, and are oriented at an acute angle with respect to one another in the advancing direction, in all operating positions during the advancement, characterized in that the extraction drum extends over at least an effective radius of the device in the radial direction of the device during advancement of the cavity.

A device for advancing a cavity in underground mining, including a rotary drive, an axial shaft that is rotatable together with the rotary drive about a longitudinal axis, exactly one extraction drum that is rotatable about an drum rotational axis, and a connecting arrangement which is connected to the axial shaft and which supports the extraction drum, the connecting arrangement being configured in such a way that the drum rotational axis and the longitudinal axis lie in a plane, and are oriented at an acute angle with respect to one another in the advancing direction, in all operating positions during the advancement, characterized in that the extraction drum extends over at least an effective radius of the device in the radial direction of the device during advancement of the cavity.

A drill bit can include a bit body having an upper portion, a central bore, and an adjustable inner gauge. The central bore can define a bore surface, and the bit body can include a plurality of fixed cutters formed on the upper portion. The adjustable inner gauge may be movably positioned within the bit body central bore to increase or decrease an exposed area of the bore surface for adjusting stability or steerability of the drill bit while forming the wellbore.

A roller reamer for downhole operations in boreholes, such as are drilled for oil and/or natural gas production, or as injection wells. An elongated main body has preferably three circumferentially spaced pockets. A roller assembly is preferably disposed in each pockets, the roller rotating in roller blocks at each end of the roller disposed within the roller blocks. Mating locking profiles, such as dovetails, lock the roller blocks within the pockets, as the roller blocks are moved longitudinally into the locking profiles, preventing any radially outward movement of the roller assembly. The roller assembly is prevented from longitudinal movement within the pockets by lock blocks also positioned within the pockets.

A roller reamer for downhole operations in boreholes, such as are drilled for oil and/or natural gas production, or as injection wells. An elongated main body has preferably three circumferentially spaced pockets. A roller assembly is preferably disposed in each pockets, the roller rotating in roller blocks at each end of the roller disposed within the roller blocks. Mating locking profiles, such as dovetails, lock the roller blocks within the pockets, as the roller blocks are moved longitudinally into the locking profiles, preventing any radially outward movement of the roller assembly. The roller assembly is prevented from longitudinal movement within the pockets by lock blocks also positioned within the pockets.

A hybrid drill bit includes both fixed cutting elements and rotational cutting elements thereon. The fixed cutting elements are affixed to a bit body and define a peripherally-located fixed cutting structure disposed radially outward of the rotational cutting elements. The rotational cutting elements define a centrally-located counter-rotational cutting structure including two hemispherical counter-rotational cutting members mounted for counter-rotation with respect to one another on an axis generally perpendicular to a bit body rotational axis.

A hybrid drill bit includes both fixed cutting elements and rotational cutting elements thereon. The fixed cutting elements are affixed to a bit body and define a peripherally-located fixed cutting structure disposed radially outward of the rotational cutting elements. The rotational cutting elements define a centrally-located counter-rotational cutting structure including two hemispherical counter-rotational cutting members mounted for counter-rotation with respect to one another on an axis generally perpendicular to a bit body rotational axis.