How to Determine Mineral Liberations by Image Analysis
Evaluations of mineral beneficiation circuits and concentrators require information on mineral liberations, on mineral recoveries and on behaviours of liberated and partly liberated mineral grains. A qualitative evaluation of mineral, liberations can be made by examining polished sections of ores with an optical microscope, but the data are not accurate enough to calculate mineral recoveries […]
Volcanogenic Massive Sulphide Deposit
The Louvicourt deposit is proving to be a very large one. Reserves now stand at approximately 30 million tons and, more importantly, the deposit contains some impressive widths of exceptionally high grade Cu-Zn-Ag-Au mineralization that should ensure its profitability in virtually any future metal price scenario. Regional Setting The Louvicourt deposit is located approximately 15 […]
Carbonatites Uses – Genesis and Evolution
Carbonates are a very rare and volumetrically insignificant family of igneous rocks composed mainly of carbonate minerals, and normally are described in terms of their habits (intrusive) and composition (mineralogy). No other association of igneous rocks exhibit as great a diversity of rock types and intrusive habit. They vary in shape and size with depth […]
Mineralization – Grasberg Copper-Gold Deposit
The Grasberg copper-gold orebody is contained with a young igneous complex of dioritic composition which intrudes limestones of the Tertiary New Guinea Group. Alteration is typical of porphyry copper deposits worldwide except that higher grade primary chalcopyrite with significant gold values is associated with a centrally located zone of strong quartz stockwork. The Grasberg […]
Rock Mechanics and Pit Slope Design
Kennecott Corporation, in joint venture with Galactic Resources Ltd., recently began operation of an open pit gold mining and milling facility near Columbia, South Carolina. The deposit consists of two ore bodies (North and South deposits) hosted in deformed and altered metavolcanics and metasediments of the Carolina Slate Belt. Emphasis includes the successful use of […]
Mine Fan Stall – Multiple-Fan Ventilation Systems
Stall or aerodynamic stall of axial-flow fans has long been recognized as an important operational problem in mine ventilation. To develop a technique for characterizing fan stall in multiple-fan ventilation networks, a research project was initiated through the Generic Mineral Technology Center for Mine Systems Design and Ground Control. Considering that fan stall is related […]
Bacterial Sulfate Reduction of Metal Contaminated Water
Bacterial sulfate reduction has been identified as one process by which constructed wetland systems remove contaminant metals from coal and metal- mine drainage. Under anaerobic conditions, sulfate-reducing bacteria oxidize simple organic compounds (CH2O) with sulfate, and thereby generate hydrogen sulfide and bicarbonate ions: SO4-² + 2CH2O → H2S + 2HCO3-…………………………………………..(1) Hydrogen sulfide reacts with many contaminant […]
Commissioning Variable Speed SAG Mill Gearless Drive
The electric operation and design features of the 11,000 H.P. variable speed SAG mill gearless drive is presented. The function of the frequency-converter, control system drive and lubrication systems are described. An analysis of the harmonic characteristic in the Supply System and Motor is presented, and the dynamic development of the stator current, speed and […]
Whole Ore Oxygen Roasting
The complex geology of the ore body prevented good segregation of a pure oxide fraction in sufficient tonnages to maintain the two circuit operation. Before plant start-up, Freeport recognized that small quantities of carbonaceous ore added to the oxide circuit would produce unacceptable reductions in gold recovery. The carbonaceous ore contributed sufficient preg-robbing organic carbon […]
Rare Earth Element and Gold-Bearing Breccia Pipes Geology
Rare earth element (REE)- and gold-bearing breccia pipes are a potentially significant economic target in the Pea Ridge iron ore mine, Washington County, Missouri. The Pea Ridge deposit is one of eight known volcanic-hosted iron ore deposits in the Middle Proterozoic St. Francois terrane, which are similar to the Olympic Dam-type deposits of Australia. Total […]