A mast and rack assembly for a mining machine includes a mast and a rack assembly coupled to the mast. The rack assembly includes outer rails and rack segments disposed between the outer rails and the mast. At least one of the outer rails overlaps two of the rack segments.

A mast and rack assembly for a mining machine includes a mast and a rack assembly coupled to the mast. The rack assembly includes outer rails and rack segments disposed between the outer rails and the mast. At least one of the outer rails overlaps two of the rack segments.

A system and method for controlling drilling of a wellbore. The method may include supporting a tubular string using a top drive connected to a block, and lowering the top drive by lowering the block. The method may also include adjusting a position of the tubular string relative to the block using an actuator coupled with the top drive, the block, or both.

A system and method for controlling drilling of a wellbore. The method may include supporting a tubular string using a top drive connected to a block, and lowering the top drive by lowering the block. The method may also include adjusting a position of the tubular string relative to the block using an actuator coupled with the top drive, the block, or both.

An underground drill comprising a frame, a drill carriage, an anchor assembly, a multi-axis input device, an electronic controller, and a mode selector. The drill carriage and the anchor assembly are operably connected to the frame. The electronic controller is configured to receive input from the multi-axis input device and produce a corresponding output signal. The mode selector has an anchor mode, wherein the output signal actuates the anchor assembly, and a drill mode, wherein the output signal actuates the drill carriage.

A duplex snubbing jack and method of snubbing pipe into a well bore which includes first and second gripping units that alternately and synchronously grip and release a length of pipe to be attached to a pipe string. The first and second gripping units are synchronously movable upward and downward toward and away from each other to push or pull the pipe through a BOP stack and into or out of a wellbore. Linear actuators are used to synchronously move the first and second gripping units. Guide rails are provided to laterally support the pipe as the pipe is pushed or pulled through the BOP stack into or out of the wellbore. The first and second gripping units are preferably slip-type spiders.

A duplex snubbing jack and method of snubbing pipe into a well bore which includes first and second gripping units that alternately and synchronously grip and release a length of pipe to be attached to a pipe string. The first and second gripping units are synchronously movable upward and downward toward and away from each other to push or pull the pipe through a BOP stack and into or out of a wellbore. Linear actuators are used to synchronously move the first and second gripping units. Guide rails are provided to laterally support the pipe as the pipe is pushed or pulled through the BOP stack into or out of the wellbore. The first and second gripping units are preferably slip-type spiders.

A horizontal directional drilling rig is described. The rig can be entirely electrically powered. The performance (or health) and/or the life cycle of individual components of the rig can be electronically monitored. This permits identification of specific individual components that are performing in a substandard manner or are not performing properly or have reached the end of their life cycle. Individual improperly performing components or components at the end of their life cycle can thus be specifically identified. The improperly performing component(s) or components at the end of their life cycle can then be replaced. In some embodiments, when a component is identified as performing improperly, the operation of other, properly functioning components of the rig can be modified accordingly to account for the improperly performing component.

A horizontal directional drilling rig is described. The rig can be entirely electrically powered. The performance (or health) and/or the life cycle of individual components of the rig can be electronically monitored. This permits identification of specific individual components that are performing in a substandard manner or are not performing properly or have reached the end of their life cycle. Individual improperly performing components or components at the end of their life cycle can thus be specifically identified. The improperly performing component(s) or components at the end of their life cycle can then be replaced. In some embodiments, when a component is identified as performing improperly, the operation of other, properly functioning components of the rig can be modified accordingly to account for the improperly performing component.

A mast assembly for a drilling rig includes a mast formed from a plurality of mast subunits. The mast assembly includes a lower drilling machine, upper drilling machine, and upper mud assembly, each of which is coupled to and movable vertically relative to the mast. The mast subunits are separable when the mast is in a transport configuration such that the LDM is positioned in a first subunit and the UDM is in a second subunit of the mast when the mast is in the transport configuration. The mast assembly may be used during a continuous drilling operation.