Froth flotation is used almost universally in the beneficiation of base metal sulfide ores. Although flotation is very efficient for particles between 150 and 10 µm in size, this efficiency drops off rapidly, as the particle sizes drop below 10 µm. Significant quantities of these ultrafine sulfide values are lost in the beneficiation of copper … Read more
Key Properties and Tests of Absorbent Clays: Clay deposits in the ground contain from 30-40% water. This leads to the remarkable observation that a thick clay bed that can support heavy machinery is by volume 50% water. Most clays when they dry shrink noticeably. Wyoming bentonite, for example, develops a “popcorn-like” appearance on drying owing to … Read more
Bubble Size The most important physical aspect of flotation is bubble size. While most people agree that small bubbles are needed for good flotation, what is meant by “small bubbles?” We have always maintained that the bubbler is the heart of the column and have spent many years developing our bubbler to its present state. … Read more
Diagrams Gy’s decomposition of the overall estimation error (OE). OE is the difference between the grade of the lot of particulate material and the grade of the sample. OE consists of two components: Total sampling error (TE) and analysis error (AE). The theory concentrates on TE. TE consists of preparation error (PE) and sampling error … Read more
Concentrating Table As far as the efficiency of the concentrating table is concerned, it has been established that a table can clean coals of 9.5mm x 0.075mm(3/8″ x 200mesh) with high efficiencies and low probable errors. It is, however, important to notice that the particle size of coal treated on a table has a significant … Read more
The advantages of the replate system are few, but significant: It greatly reduces the amount of slag produced. Since less slag is produced, the manhours and equipment required to handle the slag are also reduced. Gold losses to slag are proportionally reduced. Steel wool costs are reduced. Steel wool replacement is done twice per year … Read more
The philosophy behind the design and construction of the mobile conveying system is to allow flexibility and rapid movement or “mobility” of conveyors to follow the production face operations on a daily basis. During the conceptual stage, Foster Yeoman engineers were challenged to develop their own unique system to meet the rigid demands that the … Read more
Precious Metal Refining: Dore is a mixture of gold and silver typically containing less than 5% base metal impurities. The exact composition varies widely depending on its source and processing history. Dore producers, in deciding whether or not to refine their dore, can custom design a facility around a single feedstock. Refiners, in contrast, must handle … Read more
Agglomeration means that the clays and fine particles contained in the ore adhere to the coarser particles and create a coating of fines around the coarse particles. When the ore has few fines and the percolation problems are not severe, the addition of a liquid may be all that is necessary to render the fines … Read more
Liberation data were obtained from polished mounts made from the various size fractions produced during the batch grinding experiments. Representative portions of each size fraction were first treated with ethanol and then mounted in a cold setting resin (EPOFIX Epoxy). To minimize segregation of particles on the basis of mass or density, the particles were … Read more