Block Caving Mining Method
Block Caving has been developed to a high degree of efficiency in the last two decades and more particularly since World War II. At the Jeffrey mine of Canadian Johns-Manville Co., in the Eastern Townships of Quebec, several innovations have increased production and decreased costs. Asbestos ore is produced at the rate of 10,000 tpd […]
Nitrates and Nitrogenous Compounds
Chemical nitrogen and the “nitrates” of commercial significance are derived mainly from three basic sources: (1) the natural deposits in the form of nitrate-bearing earth and clay, which, being largely water-soluble, can exist only in the most arid portions of the earth; (2) coal, which yields not only nitrogen but also the additional by-product hydrogen […]
Solvent Flooding
One-third to one-half of the original oil is left in most reservoirs even after thorough gas driving or waterflooding. In contrast, essentially all of the oil contacted can be recovered by flooding with a solvent (a fluid miscible with the reservoir oil). It is not economical to fill a reservoir with solvent since the value […]
Grinding with Low Speed Under-Loaded Ball Mill
The small ball mills and rake classifiers in the London concentrator were replaced by one large ball mill and one hydraulic classifier. This new ball mill was designed oversize so that it could be operated at slower than normal speed. The proper operating conditions were established and the results published. In 1953 this study was […]
Morenci Reduction Works – Milling Practices
The Morenci concentrator of the Phelps Dodge Corporation is a part of the project that was completed after five years had been spent in development of the open-pit mine, equipment and process testing in the former No. 6 concentrator, and construction of the reduction works. The reduction works, of which the concentrator is a part, […]
Monazite
Monazite formerly was described as moribund, but, in the light of recent developments, it is no longer so. It is the common source of the rare earths and thorium, both of which are becoming progressively important in industrial and other applications. Moreover, by the action of foreign governments, the sources on which the United States […]
Mineral Fillers
Powdered nonmetallic minerals and rocks of many different types are used extensively in industry for incorporation in compositions and manufactured products The term “mineral filler” is commonly employed to designate a material that is used for a specific purpose but not as an essential or reactive component Such a definition is not without objections, and […]
Mining in Rhodesia
The Roan Antelope concentrator was originally designed with a nominal milling capacity of 6000 tons of copper ore per day but this was subsequently considerably exceeded. In broad outline the plant consisted of two No. 30 McCully gyratory crushers for coarse crushing, five 5½-ft Standard Symons crushers in open circuit for secondary crushing, ten No. […]
Grinding Energy Transfer by Impact
The transfer of kinetic energy of translation into other forms of energy by impact is a fundamental process in most crushing and grinding operations. During and after the impact process the original source energy may be accounted for in any of the following possible forms: Kinetic energy of translation of both the impacted and impacting […]
Lime – Quicklime & Limestone
Lime is a very general term applied to products of limestone, in popular treatises often incorrectly, including ground or pulverized limestone used in agriculture. When used without qualifying adjective, the term usually means burned or calcined limestone, or quicklime, or calcia. Limestone is burned (roasted or calcined) in furnaces known as lime kilns by direct […]