Abstract: The present invention provides apparatus and method for drilling a wellbore wherein a pilot wellbore section is drilled with a bit which section is enlarged by a trailing underreamer to the desired size. One or more steering sections between the underreamer and the drill bit are utilized for maintaining and changing the drilling direction. Each steering section includes a plurality of independently adjustable force application devices on a non-rotating sleeve. If an expandable liner is used, then an expansion device disposed above the underreamer expands the liner during retrieval of the drilling assembly to the surface.

Abstract: A drilling liner having a core bit at its bottom end is carried along with a pilot bit on an inner bottom hole assembly driven by a downhole mud motor. In one embodiment, the motor is powered by mud carried by an inner string. Alternatively, the inner string may be omitted and the flow of mud through the liner powers the motor: this requires a locking tool for locking the motor assembly to the outer assembly. Once an abnormally (high or low) pressured zone has been traversed, the liner is set as a casing, the inner assembly is pulled out, and drilling may be resumed using a conventional tool. Directional drilling is accomplished by having an MWD device for providing directional information and having directional devices on the inner and outer assembly. These include retractable steering pads. Expandable bits, under-reamers and jetting nozzles may also be used in the drilling process.

Abstract: In the plough pick arrangement according to the invention for mining ploughs or coal ploughs, the plough pick is held in the socket of a pick holder. On that side of the pick holder which is leading in the working direction of the plough pick a pick lead-through opening is provided through which the pick can be inserted by its shank until it reaches a rear stop and is retained by a securing device. The pick can be removed from the socket through the same opening, after the securing device has been released, when pick replacement is necessary. This makes it possible to insert the pick into and remove it from the pick holder, not from the working side, but from the front of the holder. The pick holder and the pick are preferably provided with co-operating bearing and guiding faces which are inclined at an oblique angle to a plane parallel with the working face so that the cutting bit of the pick moves away from the working face when the pick is removed.

Abstract: The pans of a scraper-chain conveyor are interconnected with a dog-bone type connector which fits into laterally open shaped pockets in the side walls of the pans. A projection on one of the ends of the connector engages in a recess closed off from the side access while a projection at the opposite end of the connector is locked in place with a swivelled-in locking plate. The plate fits into compartments in the side wall of the associated pan. The plate carries a resilient pin at one end which fits into recesses in one of the compartments while the opposite end of the plate has a tongue which snaps into a recess in the base of the opposite compartment.

Abstract: A conveyor channel section has shaped side walls composed of superimposed rolled profiled strips identical in construction and shape A floor plate extends between the side walls and projects between inclined curved wall portions of upper and lower profiled strips. Longitudinal welds join the floor plate to the ends of the wall portions The wall portions merge with flanges extending inwardly of the floor plate and with ribs extending in an opposite direction outwardly of the floor plate at the level of the flanges. Spill plate holders are welded to the exteriors of the side walls between the ribs and connectors at the ends of the side walls permit adjacent channel sections to be joined together with the aid of coupling members.

Abstract: A channel section or pan for a scraper-chain conveyor has a floor plate welded between side walls. The floor plate has reduced thickness end regions which provide upper and lower tongues which establish joints with corresponding complementary tongues of the floor plates of adjacent pans. Each tongue has a prominent curvilinear profile in plan view with several smooth curved projections and depressions transverse of the floor plate.