Abstract: Rock bolts comprising an expandable tube having a longitudinally extending depression disposed between two curved outer portions of the tube, wherein the depression defines a channel having an opening defined between the two curved outer portions of the tube and the width of the opening is at least 10% of the width of the tube and/or a coating layer covers at least a portion of the expandable tube. Also, a method of manufacturing a rock bolt comprising forming an expandable tube comprising a longitudinally extending depression disposed between two curved outer portions of the tube, crimping a proximal end of the tube to form a crimped portion, and placing a sleeve around the crimped portion. Prior to crimping, a temporary spacer is placed in the channel in a portion of the tube adjacent to the portion of the tube that will be crimped.

Abstract: An overcast system to block an intersection between two or more mine passageways so as to prevent the mixture of intake air with return air. The overcast system includes a first sidewall formed of one or more prefabricated panels, a second sidewall formed of one or more prefabricated panels, and a top member formed of one or more prefabricated panels, such that the top side spans the width between the first sidewall and the second sidewall. A fire-resistant coating is applied to at least a portion of the first sidewall, the second sidewall, or the top member to provide an air-tight, fire-resistant structure. Each of the one or more prefabricated panels is formed from a composite material having one or more structural studs embedded at least partially therein.

Abstract: A testing apparatus includes a frame having a top end and a bottom end, a weight block movable between the top end and the bottom end, a guide member supported by the frame and receiving the weight block, and a protection mechanism having a stopper and an actuator. The stopper being operatively connected to the actuator and movable between an extended position and a retracted position with the stopper being configured to restrict the movement of the weight block when in the extended position.

Abstract: A steel set assembly includes a first pair of legs and a second pair of legs with the first pair of legs being spaced from and positioned opposite the second pair of legs. First and second beams are provided with the first beam being secured to one leg of the first pair of legs and one leg of the second pair of legs. The second beam is secured to the other leg of the first pair of legs and the other leg of the second pair of legs. A panel is secured to the first and second beams and includes a base having a top surface and a bottom surface, a block having a top surface and a bottom surface, and a pad. The block is secured to the base and the pad is positioned between the top surface of the base and the bottom surface of the block.

Abstract: A steel set assembly includes a first pair of legs and a second pair of legs with the first pair of legs being spaced from and positioned opposite the second pair of legs. First and second beams are provided with the first beam being secured to one leg of the first pair of legs and one leg of the second pair of legs. The second beam is secured to the other leg of the first pair of legs and the other leg of the second pair of legs. A panel is secured to the first and second beams and includes a base having a top surface and a bottom surface, a block having a top surface and a bottom surface, and a pad. The block is secured to the base and the pad is positioned between the top surface of the base and the bottom surface of the block.