I was asked to “size/design” the crushing and grinding circuit required to process 200 TPD of a mystery ore = without hardness or much sizing data. All I had were a set of videos showing how the current 50 TPD plant worked at feeding the gold leaching carbon adsorption plant. I had to improvise a bit. The current “a la criolla” setup I was given was:
- A screen
- A 6″ x 10″ jaw
- A roll crusher
- A 4′ x 4′ ball mill
It was commented that the roll crusher was difficult to operate due to ore humidity/moisture. Allegedly, the rolls were to crusher 3/4″ to 1/2″. The ball mill is running a 4″ ball to feed a carbon leach with a P80 of 74 microns. After watching the 2 videos here below, I came up with this idea:
At 100% operating time, the 250 x 750 mm primary jaw crusher should be capable of crushing 300 TPD at a discharge product of <1.5″ while the smaller 150 x 750 mm secondary crusher should take the 1″ screen oversize and produce <3/4″ at a rate >200 TPD. My design assumes the preceding vibratory screen will reduce the mass feeding the small gap jaw by 50%. I based this idea on the old multi-jaw concept patented way back for fine crushing using low cost jaw crushers. See this Multi Jaw for fine crushing concept.
For simplicity, the grinding mill is sized as the largest greased trunnion (lubeless) skid mounted ball mill I could find and comes in as a 2.1 m diameter mill operated at 78-80% critical. This mill should grind 25mm rock of BWi 15 to P80 74 um at 10 TPH.
My calculated horsepower is 225-250 HP but, since it is cheap at the factory, I put on 300 HP.
If the double jaw crusher arrangement has the desired outcome of a P80 = 20 mm, this will ball mill will perform better yet. The trunnion diameter needs to be small enough to hold 19 tonnes of 2.5-3″ balls (40%).