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Offering support in underground mines

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Global Mining Review,

In underground mining, it is necessary to support the roof to prevent areas that have already been mined from collapsing. Since the 1950s, the primary method for supporting the roof has been the installation of roof bolts. Roof bolting is one of the most basic and necessary functions in underground mining operation, and over time has become more highly specialised. Today, many operations are requiring equipment predominantly dictated by mine conditions and individual customer desires.

Offering support in underground mines

One of the major issues underground operations continue to face is operator exposure to certain inherent hazardous conditions. These can include falling rock from the roof, rib and face; tripping hazards; bending, twisting and lifting hazards; high noise levels; and chemical fume exhaust.

An enclosed, filtered operator’s cab aids in alleviating many of these hazards. Fletcher’s custom designed air conditioner system filters the mine air, providing the operator added protection from diesel particulate matter and ambient mine dust. This system has proven to provide one of the highest protection levels NIOSH has recorded. This feature is offered across Fletcher’s metal/non-metal product lines.

Included in this product line is the Fletcher model 3023-AD roof bolter. This machine’s bolting system uses a compact KRM module designed to allow the operator to drill and install bolts remotely from the operator’s cab. The system consists of two drill masts (one to drill and one to bolt) mounted on a lifting boom with an automatic levelling system. The remote operation is made possible through a bolt rack which is designed to hold 12 bolts with 6 x 6 in. (152 x 152 mm) plates. Front and rear stabilisers help secure the machine’s position during drilling and bolt installation. A rotary drill head with hydraulic drill feed and rotation control is standard. Resin cartridges are pneumatically inserted from the cab. Standard mast configuration accommodates 8 ft (2.4 m) length bolts. Bolt on equipment allows the carousel to extend and retract, allowing the machine to accommodate different bolt lengths. This remote design helps alleviates some of the material handling burdens imposed on a roof bolter operator.

The 3023-AD is equipped with a boom engineered to lift, swing, and extend allowing multiple installations from one chassis position. The rotating bolt module is designed to rotate 180° to the left of vertical to drill the floor and the left rib, as well as rotate 90° on the right side to provide drilling access to the right rib. This rotation capability allows the operator to drill the roof, rib and floor.

The 3023-AD also offers a dust sampling system. This system allows the operator to collect dust samples without exiting the cab. With this system, the operator can determine the conditions of the strata and accurately determine the mining direction. The dust collection system optimises operator safety by allowing them to remain in the operator’s cab while this process takes place. This feature provides a safer, more efficient process to evaluate the seam conditions in the path of drilling.

The Fletcher model 3023-AD meets the needs of operations in heights from 10 ft 10 in. (3.3 m) to 25 ft 10 in. (7.67 m) and is designed around the ability for the operator to accomplish most basic functions from the enclosed, filtered cab. This is supported though the operator’s ability to remotely perform multiple installations from one position, due to the flexibility of the boom paired with the dual mast and bolt carousel. The dust sampling system also provides a safer alternative, which does not require the operator to exit the cab.

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