Small-scale hard rock miners do not have the luxury of a fully equipped industrial-grade mill with flotation and cyanide leaching to process their ore and recover values. We are usually limited by practicality, finances and permitting to a simple crushing and grinding circuit, with a gravity recovery system for the free milling values and value-containing sulfides.
MBMM offers several options with our 1 or 2 ton/hr turn-key ore processors. We offer them with either a hammer mill or a ball mill. Our 4-5 tph system comes with a ball mill only.
The hammer mill version of our turn-key ore processors is less initial cost, but higher maintenance cost ($10-15/ton, plus down time). It will produce ground material with 70% passing a 30 mesh screen and 50% passing a 50 mesh screen. The hammer mill is generally suitable for bulk sampling or limited production of 200-500 tons of material, and we often get 60-80% recovery of the gold. If you want to upgrade later, the hammer mill can be replaced with a ball mill and all the rest of the machinery stays the same. Hammer mill tailings with enough values can be re-run in the ball mill at a finer grind. Take a look at the procedure to determine the liberation size for a specific ore type.
If you want to process more tonnage, or grind finer, we recommend a ball mill right from the start. It will go for months with no maintenance ($1-2/ton cost) and can be adjusted to grind from 50-200 mesh (through-put varies). Establishing the practical liberation size is important and can be easily found by running some ore through the system, screening the tailing into 3 fractions – +50 mesh, 50-100 mesh and <100 mesh – then assaying each fraction. If significant gold is found in the coarser fraction(s), adjust the machinery so the grind size is finer to increase the percentage recovery.
All of our turn-key systems are simple to operate and maintain. They are mechanical systems powered by electric motors with no computers, chemicals or electronics. The gold recovered from the shaker table is easy to melt into a bar and sell to a gold buyer without further processing or delay. Sulfides with values can be saved from port #3 and sold to a refiner. Many of our customers pay for their machinery in a short period of time.