Selective mining methods

Mining is by the open-pit method, and, because of the chemical irregularity of the deposit, selective mining methods have to be employed. Visual distinction between the various grades of ore is difficult, so identification has to be made by determining the two principal contaminants, lime... 

Hugh Chipman is Associate Professor and Canada Research Chair in Mathematical Modelling in the Department of Mathematics and Statistics at Acadia University. His interests include the design and analysis of experiments, model selection, Bayesian methods, and data mining. 

Erosion is controlled by grading to create terraces and diversions that decrease slope lengths and direct runoff water to safe outlets. During backfilling, the permeability of the fill can be controlled to achieve the desired degree of water percolation. The requirements for backfill and grading in reclamation operations should be considered in the selection of mining method. 

The number of features combined in a vector-type representation is indicative of the dimensionality of the problem space. Low-dimensional representations, on the one hand, allow easy visualization but are most often not very discriminative. Highdimensional representations, on the other hand, such as those encoded in Daylight fingerprints [23], MACCS keys [24], or UNITY fingerprints [25], provide more detailed accounts on structural or chemical variations. However, this is achieved at the cost of visualization. Part of these high-dimensional representations describe specific local features of molecules, and because not all molecules in the data contain these features, gaps or zeros are introduced in the data representation. For certain data mining methods, this could be problematic. In many cases, dimensionality reduction procedures are applied to reduce the complexity of the representation. The reduction of the dimensionality is accomplished by means of 1) variable selection procedures, 2)... 

Most conventional coal cleaning operations utilize gravity methods for the coarser size fractions and surface treatment methods for the finest particle sizes (Riley and Firth, 1993). The selection of equipment, especially for the finer sizes, depends on the mining method, coal hardness, and size distribution and amounts thereof. Typical of these is a dense-media cleaning process (Fourie, 1980) which use dense-media vessels or jigs for the coarsest size usually +3/8 in., dense-media cyclones, concentrating tables or jigs for the 3/8 in. x 28-mesh size, water-only cyclones or spirals, and sometimes flotation for the 28 x 100-mesh size and flotation for the -100 mesh. 

Most conventional coal cleaning facilities utilize gravity methods for the coarser size fractions and surface treatment methods for the finest particle sizes (Riley and Firth, 1993). The selection of equipment, especially for the finer sizes, depends on the mining method, coal hardness, and size distribution and amounts thereof. 

The mining method selected for use is large scale open pit mining. The crushed (80% < 8mm) ore is agglomerated and conveyed to the heap pad. After 13 to 14 months of bioleaching on the primary pad, the leached ore is reclaimed, conveyed and re-stacked onto the secondary heap pad. After secondary leaching, the barren ore will remain permanently in the secondary heaps. In the... 

The selection of a mining method to use for a particular uranium ore deposit is governed only by safety and economic considerations. Underground, open-pit mining, and in situ leaching techniques are used to recover uranium. 

Data Mining is the core of the more comprehensive process of knowledge dis-coveiy in data bases (KDD). However, the term data mining" is often used synonymously with KDD. KDD describes the process of extracting and storing data and also includes methods for data preparation such as data cleaning, data selection, and data transformation as well as evaluation, presentation, and visualization of the results after the data mining process. 

A similar process has been devised by the U.S. Bureau of Mines (8) for extraction of nickel and cobalt from United States laterites. The reduction temperature is lowered to 525°C and the hoi ding time for the reaction is 15 minutes. An ammoniacal leach is also employed, but oxidation is controlled, resulting in high extraction of nickel and cobalt into solution. Mixers and settlers are added to separate and concentrate the metals in solution. Organic strippers are used to selectively remove the metals from the solution. The metals are then removed from the strippers. In the case of cobalt, spent cobalt electrolyte is used to separate the metal-containing solution and the stripper. MetaUic cobalt is then recovered by electrolysis from the solution. Using this method, 92.7 wt % nickel and 91.4 wt % cobalt have been economically extracted from domestic laterites containing 0.73 wt % nickel and 0.2 wt % cobalt (8). 

The method of mining is somewhat like driving two sets of tunnels at right angles through the strata. Most mines of this type do not present any hazard from methane and therefore non-permitted explosives can be used. The selection of powder or gelatine type of explosive depends on the nature of the rock and particularly on the wetness of the mine. 

Most catalysts originally developed for C=C bonds show a rather poor performance for the hydrogenation of many ketones. However, this situation changed dramatically when it was found that selected Ru-binap and later Ru-binap-dia-mine complexes achieve excellent enantioselectivities, as well as very high TONs and TOFs, for a variety of ketones [92]. Since then, it has been demonstrated that many a- and yS-functionalized, as well as aromatic ketones, are suitable substrates for hydrogenation with industrially viable catalytic results. For the reduction of various ketones biocatalytic methods are an industrially viable alternative to chemocatalysts [15]. 

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