Room-and-pillar mining will be used to extract ore from the deposit at a nominal rate of 3.7 million tons per year. Equipment selection includes state-of-the-art, high-horsepower continuous mining equipment currently in use throughout the world in the coal, trona, and potash sectors. During the course of the Feasibility Study, ICP performed linear cutting tests on the polyhalite core. A continuous mining equipment manufacturer reviewed the linear cutting test results, performed additional testing, and recommended the use of drum-type continuous miners.
The ore bed will be accessed via a 25-foot diameter, two compartment mine ventilation and service shaft, and a 12,000-foot long slope (also referred to as a “ramp” or “decline”) inclined at 8.5 degrees. The 1,525-foot deep shaft will have an intake air compartment, equipped with an emergency escape hoist and cage as well as electrical high voltage and communication cables. The second compartment will be used for return air and will contain fresh water and mine discharge water piping to prevent freezing during the winter months. General mine ventilation will be accomplished with dual 11-foot fans installed in parallel on the return side of the shaft. The slope provides flexibility to accommodate increased underground production as needed. Ore will be transported to the surface via a 60-inch slope conveyor with a capacity of 4,000 tons per hour.
The Feasibility Study recommends the use of dual split super section (DSSS) mining methods. Parallel sets of main entries are developed five to seven entries wide each. Production panels are developed up to 1000 feet wide to accommodate the DSSS concept of operating two continuous miners side by side using a centrally located single belt conveyor. DSSS supports the use of common equipment such as section scoops, forklifts, and section conveyors. DSSS keeps both capital and operating costs as low as possible.