Innovations in Stacking and Crushing Equipment for Mining

Shot Rock Conveyor

The genesis of the Shot Rock Conveyor took place over a number of years. Once again this was an in-pit operation. The challenge was to take material directly from a rope shovel and convey it to a nearby excavated area. While this could be accomplished easily enough with a number of dozers working in a dozer-push operation, the operational costs were too high. Adding to the challenge was the fact that some of the overburden material could be up to 1.5 metres in size.

The FLSmidth design team developed a machine that combined sizer, traditional boom spreader and mobile stacking conveyor technologies. The shot rock conveyor is a specialized machine concept, designed to perform a specific task for a very specific application. The machine is fully mobile, with a carbody mounted on dual crawler tracks at both the head and tail sections.

The tracked carbodies are sized and positioned to share the weight of the machine equally. The carbody at the tail end is connected with a gimbal bearing, allowing it to both rotate and move to accommodate the terrain. The head carbody is designed to slew relative to the conveyor truss it supports. Leveling cylinders on the head carbody keep the machine level.

The shot rock conveyor’s loading hopper is located at the tail section. It has enough capacity to hold three buckets of material (up to a total of 240 cubic yards or approx. 183.5 cubic metres). The apron feeder at the bottom of the hopper meters the flow of material into the twin-roll sizer where it is reduced to a conveyable size. The sized material drops onto the loading area of the main belt conveyor.

The main conveyor section has a robust, open truss structure. This structure supports the belt and idlers. Parts of the head section of the conveyor are smaller trusses connected with pin joints and are supported by wire ropes to relieve induced moments. The shot rock conveyor has its own electrical equipment room with switchgear, motor control centres and other control equipment, including a programmable logic controller and maintenance local control panel. The initial design has remote control panels for off-board operation.

The need for innovation in all areas of material handling equipment will continue. One great challenge is in the area of operations where, for example, relocating a semi-mobile crushing station can run up to USD 10 million. Other areas, such as production efficiency, safety, and the need to address more stringent environmental requirements, continue to make equipment innovation an even more vital concern. n