As voids are created because of the extraction of coal underground, artificial support systems, in addition to roof bolting, often are required to stabilize the mine opening to provide a safe working environment. Various constructions of cribs made from wood timbers are used most often Although these supports are simple in design with a unit … Read more
Studies estimate that 156 billion tons of coal, representing 68 pct of the minable reserves in the United States, is subject to multiple-seam mining. Historically, room-and-pillar mining has dominated coal production, and this mining method has been the focus of most multiple-seam research. Advances in Longwall Mining Method have made this system more economically attractive … Read more
Since the introduction of rock bolts 40 years ago, their use to support and stabilize openings in U.S. mines has steadily increased. The number of roof falls has been significantly reduced where rock bolts have been installed, and they are now the primary support required by the Mine Safety and Health Administration (MSHA) in most … Read more
In situ leach mining (ISLM) is an advanced selective mining technique used for the exploitation of copper oxide deposits. ISLM involves the injection of a solution into a deposit, the dissolution and mobilization of target metals, and the recovery of this solution for processing. The vast supply of raffinate, a sulfuric acid by-product resulting from … Read more
Cyanide has been used in the mining industry for gold and silver recovery for almost a century. It is cost-effective and achieves excellent extractions from a wide range of ores. However, considerable interest has been expressed in non-cyanide lixiviants since the early 1980’s. In addition to environmental considerations, several factors have influenced the search for … Read more
Pelletization is the unit operation of agglomerating moist particulate materials by tumbling in horizontal rotating drums or inclined discs. Pelletization has extended the life of iron ore industry by enabling the treatment of low grade iron ores which are available in large reserves through out the world. Iron ore pelletization is a two step process … Read more
Flocculation is the process of agglomerating fine particles in solid-liquid suspension by using a high molecular weight long chain polymer as a flocculant. It is used industrially as a pretreatment step to solid-liquid separation and also as a separation method for recovering valuable minerals from gangue using selective flocculation. Spontaneous floc formation takes place due … Read more
The dewatering of flocculated clay suspensions by compression in a centrifugal field has been investigated. The results are evaluated with regard to both direct applicability to centrifugal dewatering, in solid-bowl centrifuges for example, and indirect applications to gravity sedimentation systems. It is well known that sediment consolidation under gravity depends on structural characteristics such as … Read more
The flotation process may be considered an interactive system consisting of many chemical, operational, and equipment variables. Changing any one of these variables causes an overall system response change. This study examines the effects of simultaneously changing the operating variables of: (1) frother concentration and air flow rate, and (2) frother concentration and collector concentration. … Read more
During several years of operation in Europe, South Africa and other countries, the Tri-Flo has demonstrated to represent a substantial improvement of the dense medium dynamic separation systems. The reasons are: high sharpness separation due to the multistage system and the application of new concepts m designing the regeneration circuit and controlling the medium rheology: … Read more