Joy’s answer to hard rock mining applications is the 12HM series continuous miners. These machines are successfully operating in trona, gypsum, potash and salt mines around the world.
As the 12HM continuous miners are the largest manufactured by Joy, the cutting system has been designed to match the machine mass. The 12HM continuous miners are available with a chainless cutterhead, ranging from a 47 1/4 inch (1200 mm) drum diameter to a 53 3/4 inch (1367 mm) diameter, as well as a RipperveyorTM cutterhead, with a drum diameter of 58 inches (1473 mm).
The 12HM traction system features a heavy-duty crawler chain, along with a heavy-duty drive system, to effectively tram the machine. Patented OPTIDRIVE AC electronics or it’s precursor, the DC microprocessor drive is coupled to a compact all-gear transmission to provide smooth, reliable service. Cutter motor feedback and traction differential features optimize sump performance in even the most demanding applications.
For applications where machine-cooling water can not be discharged onto the cut material through water sprays, the 12HM continuous miner can incorporate an onboard closed loop cooling system. The coolant is pumped through the electrical enclosures and motors, through an onboard heat exchanger, and returned to an onboard coolant reservoir. Coolant flow and temperature are monitored through JNA to insure proper operation.
The conveying system on the 12HM features a 38 inch (965 mm) conveyor for increased production capability. In addition to the dual drive gathering head system for loading, the 12HM is also equipped with single rear conveyor chain drive or optional dual rear conveyor chain drive. The cam style take-up automatically provides proper conveyor chain adjustment as the conveyor swings.