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This is the first attempt at compilation of papers to serve as a practical guide for the selection, screening and evaluation of chemical reagents for the engineer in the mineral processing industry. The 31 papers are split into 5 sections: Plant practice which includes, plant practice in nonmetallic flotation, sulphide flotation, and iron ore processing, steps in reagent development,and participation of industrial research in commercialisation of new chemical products; Collectors and frothers which includes, reagent testing, evaluation of reagents for flotation of sulphide ores, the industrial practice of sulphide mineral collectors, cationic flotation reagents for mineral benefication, fatty acid collectors, sulphonate-type flotation reagents, and frothers; Modifying reagents which includes, pH regulators, dispersants, organic polymers as depressants, inorganic depressants, scale detection and control during mineral benefication, and antiscaling reagents; Chemical processing which includes, the role on nonpolar oils as flotation reagents, practical considerations in the evaluation and selection of solvent extraction reagents, and a laboratory and pilot plant program for the development of a solvent extraction process; Dewatering and other reagents which includes, dust control chemicals and freeze conditioning agents in the mining industry, finding the right anticake reagent, activated carbon for precious metal recovery, practical aspects of flocculant use in hydrometallurgical procesing, flocculant testing, chemical dewatering aids for mineral and coal slurries, reagents used in coal preparation, coal frothers, and factors influencing choice of coal flotation reagent., This is the first attempt at compilation of papers to serve as a practical guide for the selection, screening and evaluation of chemical reagents for the engineer in the mineral processing industry. The 31 papers are split into 5 sections: Plant practice which includes, plant practice in nonmetallic flotation, sulphide flotation, and iron ore processing, steps in reagent development,and participation of industrial research in commercialisation of new chemical products; Collectors and frothers which includes, reagent testing, evaluation of reagents for flotation of sulphide ores, the industrial practice of sulphide mineral collectors, cationic flotation reagents for mineral benefication, fatty acid collectors, sulphonate-type flotation reagents, and frothers; Modifying reagents which includes, pH regulators, dispersants, organic polymers as depressants, inorganic depressants, scale detection and control during mineral benefication, and antiscaling reagents; Chemical processing which includes, the role on nonpolar oils as flotation reagents, practical considerations in the evaluation and selection of solvent extraction reagents, and a laboratory and pilot plant program for the development of a solvent extraction process; Dewatering and other reagents which includes, dust control chemicals and freeze conditioning agents in the mining industry, finding the right anticake reagent, activated carbon for precious metal recovery, practical aspects of flocculant use in hydrometallurgical procesing, flocculant testing, chemical dewatering aids for mineral and coal slurries, reagents used in coal preparation, coal frothers, and factors influencing choice of coal flotation reagent.

The strategy presented can be tailored to fit a wide range of audits. This flexibility is a key feature of the approach., The strategy presented can be tailored to fit a wide range of audits. This flexibility is a key feature of the approach.

Mill design changes have been dictated by the desire to minimise capital and operating costs. A key to this minimisation is the design of metallurgically efficient flotation circuits, incorporation of new flotation equipment wherever possible and modifying existing mills to utilise new advances in circuit design and flotation cell design concepts., Mill design changes have been dictated by the desire to minimise capital and operating costs. A key to this minimisation is the design of metallurgically efficient flotation circuits, incorporation of new flotation equipment wherever possible and modifying existing mills to utilise new advances in circuit design and flotation cell design concepts.

Metallurgical auditing of the plant was conducted to find ways to modify the circuit to process hard ore without sacrificing throughput. In addition, unit operations were optimised to increase recovery and reduce operating cost. The results of modifications made are discussed., Metallurgical auditing of the plant was conducted to find ways to modify the circuit to process hard ore without sacrificing throughput. In addition, unit operations were optimised to increase recovery and reduce operating cost. The results of modifications made are discussed.

The existing regrind circuit at the Climax Operations uses sodium cyanide and Nokes reagent to reject pyrite, copper and lead minerals. Metallurgical and mill flotation were performed to investigate the effects of conditioning time, pH, and concentration of depressants on this process. The rejection of impurities was dependent on conditioning time and the rejection of copper strongly dependent on pH. The recovery of molybdenite was independent of the variables investigated., The existing regrind circuit at the Climax Operations uses sodium cyanide and Nokes reagent to reject pyrite, copper and lead minerals. Metallurgical and mill flotation were performed to investigate the effects of conditioning time, pH, and concentration of depressants on this process. The rejection of impurities was dependent on conditioning time and the rejection of copper strongly dependent on pH. The recovery of molybdenite was independent of the variables investigated.

Comminution circuits use a combination of crushers, rod mills, ball mills, pebble mills, autogenous and semiautogenous grinding in many configurations. The three basic circuits, however, are crushing and grinding, crushing with subsequent pebble mill grinding and autogenous grinding with minimal crushing. Different circuits are preferred in different areas of the world. The selection of a comminution circuit is based on technical, economic and socio-political considerations. New variations of the basic circuits will continue to be developed to minimise capital and operating costs., Comminution circuits use a combination of crushers, rod mills, ball mills, pebble mills, autogenous and semiautogenous grinding in many configurations. The three basic circuits, however, are crushing and grinding, crushing with subsequent pebble mill grinding and autogenous grinding with minimal crushing. Different circuits are preferred in different areas of the world. The selection of a comminution circuit is based on technical, economic and socio-political considerations. New variations of the basic circuits will continue to be developed to minimise capital and operating costs.

A plant can meet design criteria provided proper attention is given during bench-scale and pilot-plant test work in order to generate the appropriate data. Once a plant is built, geologists, miners, metallurgists, environmentalists and management should have prior communication and work together to eliminate problems caused by misconception., A plant can meet design criteria provided proper attention is given during bench-scale and pilot-plant test work in order to generate the appropriate data. Once a plant is built, geologists, miners, metallurgists, environmentalists and management should have prior communication and work together to eliminate problems caused by misconception.

A brief review of auditing procedures, including diagnostic leach testing, is presented, an audit being a formalised, thorough and systematic examination of a system. Three case studies are presented. A global audit was carried out in a gold/silver leaching plant in Mexico with the objective of identifying opportunities for general improvement. It involved a plant visit, discussions with senior personnel, and a review of metallurgical and maintenance data. Potential reductions in operating costs were identified, and a specific audit of the grinding circuit was recommended. The case study illustrating a specific audit involves a cyanidation plant that had throughput reduced from 9 000 to 5 000 tonnes/day because harder ore was being received. The grinding circuit was modified and grinding efficiency improved. The use of diagnostic leach testing is demonstrated at a plant processing ore from three different mines. From the test results, it was recommended that the gravity circuit be eliminated and the extra mill used for a finer primary grind. Costs are given for the options in the case studies., A brief review of auditing procedures, including diagnostic leach testing, is presented, an audit being a formalised, thorough and systematic examination of a system. Three case studies are presented. A global audit was carried out in a gold/silver leaching plant in Mexico with the objective of identifying opportunities for general improvement. It involved a plant visit, discussions with senior personnel, and a review of metallurgical and maintenance data. Potential reductions in operating costs were identified, and a specific audit of the grinding circuit was recommended. The case study illustrating a specific audit involves a cyanidation plant that had throughput reduced from 9 000 to 5 000 tonnes/day because harder ore was being received. The grinding circuit was modified and grinding efficiency improved. The use of diagnostic leach testing is demonstrated at a plant processing ore from three different mines. From the test results, it was recommended that the gravity circuit be eliminated and the extra mill used for a finer primary grind. Costs are given for the options in the case studies.

This paper discusses the need for periodic auditing of mineral processing flowsheets and the pontential benefits a company can gain from a study of this nature. A carefully designed flowsheet auditing can have a significant impact on the metallurgical performance in the plant. Several case studies illustrating the potential benefits that can be attained from flowsheet auditing of mineral processing plants are discussed., This paper discusses the need for periodic auditing of mineral processing flowsheets and the pontential benefits a company can gain from a study of this nature. A carefully designed flowsheet auditing can have a significant impact on the metallurgical performance in the plant. Several case studies illustrating the potential benefits that can be attained from flowsheet auditing of mineral processing plants are discussed.

Climax by-product-plant tailings assayed 0.019 % WO3. Pilot-plant and laboratory tests were performed to investigate the possibility of recovering additional tungsten from the by-product-plant tailings. The paper discusses the methodology used in the study and the results of this investigation., Climax by-product-plant tailings assayed 0.019 % WO3. Pilot-plant and laboratory tests were performed to investigate the possibility of recovering additional tungsten from the by-product-plant tailings. The paper discusses the methodology used in the study and the results of this investigation.

A series of potential non-oil based collector classes were identified and evaluated in the laboratory against the current collector system used at the Climax mill, Colorado. The metallurgical performance of each collector class was related to their chemical structure. Mercaptan, xanthogen, formate, xanthic ester and xanthate collectors were found to exhibit good potential as substitutes for vapour oil, whereas mercaptobenzothiozoles, thiourea- and carbamate based compounds, dithiophosphates and dithiophosphines showed poor potential as collectors. Fatty acids and their derivatives and amine-based compounds were found to act as depressants., A series of potential non-oil based collector classes were identified and evaluated in the laboratory against the current collector system used at the Climax mill, Colorado. The metallurgical performance of each collector class was related to their chemical structure. Mercaptan, xanthogen, formate, xanthic ester and xanthate collectors were found to exhibit good potential as substitutes for vapour oil, whereas mercaptobenzothiozoles, thiourea- and carbamate based compounds, dithiophosphates and dithiophosphines showed poor potential as collectors. Fatty acids and their derivatives and amine-based compounds were found to act as depressants.

Cultural differences are discussed that mining personnel may encounter when posted overseas or to other parts of their own country. Awareness of the differences, which may be severe, is necessary in order to avoid problems arising. Aspects discussed include the role of women, dress codes, forms of greeting, skin colour, caste, religion, age and sex, religious and other beliefs, eating and drinking habits, tribal and other institutions, language and artistic expressions., Cultural differences are discussed that mining personnel may encounter when posted overseas or to other parts of their own country. Awareness of the differences, which may be severe, is necessary in order to avoid problems arising. Aspects discussed include the role of women, dress codes, forms of greeting, skin colour, caste, religion, age and sex, religious and other beliefs, eating and drinking habits, tribal and other institutions, language and artistic expressions.

There has been significant interest recently in the concept of retreatment of tailings to enhance recovery and hence revenue while maintaining high throughput. The technical and economic factors that need to be considered in the evaluation of the feasibility of tailings retreatment, including the potential feed streams (rougher or cleaner tailings) and processing options (physical beneficiation or chemical processing), are discussed. The valuation is applied to tailings from a primary molybdenum plant where tungsten was recovered as a by-product., There has been significant interest recently in the concept of retreatment of tailings to enhance recovery and hence revenue while maintaining high throughput. The technical and economic factors that need to be considered in the evaluation of the feasibility of tailings retreatment, including the potential feed streams (rougher or cleaner tailings) and processing options (physical beneficiation or chemical processing), are discussed. The valuation is applied to tailings from a primary molybdenum plant where tungsten was recovered as a by-product.