Aqueous polydisperse suspensions of angular (milled) or spherical (atomised) ferrosilicon alloy powders are widely used in mineral, aggregate and scrap separation processes as a dense medium. Table I shows the typical range of Dense Media Separation water analyses (analysing the supernatant after allowing the ferrosilicon solids to settle) taken from three diamondiferous-kimberlite circuits, from which it … Read more
The centrifuge modeling technique is a powerful tool for geotechnical engineering in general. It has been used for over sixty years to model soil behavior. Regarding phosphatic clays, centrifuge research has been actively conducted in the last decade by several investigators to predict the field consolidation of these clays. In this technique, a physical model … Read more
Previous work has shown that significant, free milling gold values exist in the Ryan Lode ore. This project used pilot scale equipment to estimate the percentage of gold recoverable by gravity methods from the circulating load of a conventional, closed-circuit, grinding mill. The pilot scale flowsheet employed three stages of gravity concentration, hydraulic classification and … Read more
The dredge selected for the project was the Para. It is purportedly the largest discountable dredge in the world. Two weeks after its arrival at the project site by rail, the Para was ready to operate. The Para has a 0.75 m (29½ inch) suction and a 0.70 m (27½ inch) discharge. It has 600 … Read more
The project consisted of installing one jig and one belt strake on each of the four grinding sections. A portion of the circulating load in the ball mill circuit is pumped to the jig. The jig is placed over the top of the belt strake. The concentrate from the jig flows onto the belt strake. … Read more
Investigations were conducted by the U.S. Bureau of Mines to develop flowsheets for the recovery of tungsten and gold from four Alaskan scheelite-bearing ores. Basic gravity concentration and cyanide leach tests were performed on all samples. About 46 pct of the tungsten and 30 pct of the gold from one sample were recovered in a … Read more
The packed jig is a column filled with corrugated diagonal packing. A slurry of mixed particles, the ore, is fed into the middle of the column. Water enters the column near the bottom as both a steady state and a pulsating flow. The pulsating water sets up a jigging action that interacts with the packing … Read more
The USBM conducted laboratory research including operating a nominal 100 lb/h pilot plant to demonstrate the recovery and concentration of chromite by gravity and flotation operations. Gravity beneficiation test results show that concentrates contained as much as 52 pct chromic oxide (Cr2O3) with recoveries of about 80 pct. Results from the bench-scale unit operations of … Read more
In ground sluicing the gravel is excavated by running water not under pressure. Booming is a variation of ground sluicing in which water is stored in reservoirs and is intermittently discharged in large volumes over short periods to obtain the maximum erosional and transporting effect on the gravel. The most favorable conditions for ground sluicing … Read more
Specific placer mining equipment is needed for each of the methods which can be classified according to the several methods of excavating and transporting the gravel, or they may be designated to correspond with the various ways of saving the gold. The actual moving of the gravel from place is always the principal concern of … Read more