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By Colin C. Brooks

The Ok Tedi gold/copper deposit of almost 800 million tonnes was found in I968 because at that time technology had just developed sufficiently to enable exploration of such an area, world markets and prices for copper encouraged exploration for large deposits of low grade ore, Papua New Guinea law encouraged exploration by groups with men, money, management and expertise necessary for successful prosecution of such a search and such groups were already operating in the country.

Jan 1, 1990

A conventional paddle-type mixer and a gravity flow mixing device were evaluated for conditioning of phosphate ore with fatty acid and fuel oil, and for acid scrubbing prior to cationic flotation. Gravity flow mixing required less residence-time, but slightly higher reagent concentrations to achieve recovery levels similar to conventional conditioning. Grade was less sensitive to reagent concentration using the gravity flow mixer. For acid scrubbing, the gravity flow mixer proved equally effective. In this paper, the effect of time, pulp density, reagent concentration, and emulsification on conditioning and acid scrubbing efficiency of the two devices will be discussed.

Jan 1, 1987

By S. K. Kawatra, A. K. Bakshi

Mineral suspensions in water show Newtonian flow properties at low percent solids. However, this changes to a non-Newtonian regime as the pet-cent solids increases. For Newtonian fluids, viscosity is independent of shear rate, hut, for non-Newtonian fluids, viscosity varies with shear rate. Therefore, if the slurry is non-Newtonian, attempting to measure the viscosity at a shear rate different from the shear rate experienced by the fluid within the process is futile. This is especially true for a hydrocyclone, where the rate of shear is different at different points within the hydrocyclone. In this case, it is very important to determine the flow type of the suspension before attempting to establish any correlation between the viscosity and the process efficiency. A new technique to distinguish such changes inflow type was developed. This involves two viscometers: a coaxial cylinder-type viscometer that measures apparent viscosity at low shear rates and a vibrating sphere-type viscometer that measures the apparent viscosity at high shear rates. For each of these instruments, special precautions were taken to allow, for the measurement of the viscosity of rapidly settling mineral suspensions. Because the vibrating sphere viscometer is operated at a much higher shear rate than the rotating viscometer, the two instruments together could determine the shear-rate dependency of the viscosity. Ground silica (80% passing 65 µm) in water was used to prepare slurries at concentrations ranging from 10% to 70% (by weight) solids. The viscosity of each slurry sample was measured simultaneously by both viscometers, and the results were compared. With this technique, it was found that all of the silica-slurry samples tested were in the Newtonian flow regime for up to 70% (by weight) solids. Methocel and Cellosize polymer solutions showed clear non-Newtonian behavior using this technique. This confirmed that non-Newtonian behavior of the silica slurries, if present, would have been detected by this arrangement.

Jan 1, 1997

By Robert L. Randall

The mineral industries have a continuing need for market forecasting and analysis for a variety of purposes, among which are organization and control of the sales effort, financial and corporate planning, and evaluation of the anticipated revenue from investment in proposed projects. For anything beyond the simplest extrapolation, some kind of economic reasoning or analysis is called for, which may or may not be incorporated into a formal or quantitative model. The principles described here apply to most of the commercially significant minerals and metals. The examples are drawn largely from the copper market, as it is the one with which I have the most practical experience. Practical forecasting is the process of analysis and synthesis from three categories of knowledge: facts and statistics, theory, and practical knowledge and informed opinion. Although many attempts have been made to build forecasts on only one of these three pillars, none has been successful as an operating procedure because of the lack of balance. There are no facts about the future-only about the present and the past. Facts can illuminate the future, but the future can be described only in terms of probability or more or less likely states of affairs-not as a continuous extension of the past and present. Likewise, theory, although useful as an organizing discipline and for providing a methodology of analysis, is inadequate for the complexities of reality. This is especially so when there is feedback between plans and forecasts to produce a new outcome and when there are significant elements of unpredictable free will, such as presidential jawboning or foreign policy considerations. Such elements are difficult to accommodate in neat theories, although they must certainly be reflected in the forecasts. Pure opinion frequently suffers from both a lack of-disciplined reasoning and the presence of biases or self-interest. While the future is unknown, it tends to cast its shadow before it; hence, forecasting is the art and science of positioning oneself so that the shadow becomes visible to the forecaster.

Jan 1, 1979

By K. N. Panigrahi

India bestowed with 6000km of the coastal belt, contains some of the richest and largest placer deposits with a mixture of heavy minerals like ilmenite, rutile, leucoxene, zircon, monazite, sillimanite and garnet. Each of the minerals is having economic value due to its inherent characteristics for industrial use in fields of paints, metallurgy, refractory, abrasive and so on. The reserves of titanium bearing minerals (ilmenite, leucoxene, and rutile) in the country is around 378 million tonnes. More than 90% of the titanium based minerals produced worldwide are utilised for making value added products in the pigment industries. Approximately 8 million tonnes of monazite reserves are available in the country from which several rare earth elements like cerium, neodymium, lanthanum, yttrium etc. can be extracted for use in several industries. The country contains a deposit of about 20 million tonnes of zircon, which is used in foundries, refractories, ceramics and chemicals. India has a reserve of 107 million tonnes of garnet and 131 million tonnes of sillimanite required for the abrasive and refractory industries respectively. Keeping in view the multifarious uses, the beach sand minerals are being exploited to have the economic growth of the nation. Although the process adopted for the separations are simple, the equipment involved are specially designed because of the nature of the material of construction. Starting from the spirals to magnetic separators, all equipments are manufactured outside India, which is not only costly, but the availability also takes much time for fulfilling the import formalities. Unlike open cast mining, beach sand mining is a environment friendly mining because dredging is implemented to cut and pump the loose sand through a slurry pump causing less damage to the surface topography as both mining and backfilling takes place simultaneously. Therefore all out efforts are made to explore the beach sand placer deposits in an economic manner to emerge as a leader in the global mineral industries.

Jan 1, 2005

By S. C. Sun

A study(1) on the sulfuric acid extraction of alumina from some Pennsylvania ferruginous clays indicated that the published electrolytic method(2)(3) seems to be more efficient than the known chemical methods (4-9) for removing iron from the leach liquor. The main disadvantages of the chemical methods are the consumption of excessive amounts of reagents and/or the precipitation of prohibitive amounts of aluminum. In the electrolytic method, iron is deposited on the mercury cathode, while aluminum is not and remains in solution. This method, however, had been handicapped by the lack of an effective and economical way to purify the contaminated mercury cathode.(7)(l0). Described herein is a scheme for cleaning the mercury cathode, and for recycling the clean mercury back into the electrolytic cell. Armed with such an apparatus, the effects of applied potential, temperature, and operation time on the electrolytic separation of iron from aluminum sulfate solutions were determined. For the sake of comparing results, a term, removability, was coined to represent the percentage of iron amalgamated per unit height of electrolyte (cm.), per unit surface area of cathode (cm.2), per unit of operation time (second).

Jan 1, 1968

By John P. Smith

As the US looks within its borders in its drive toward energy independence, economical coal transportation, particularly from vast western reserves, becomes an increasingly difficult but compelling challenge for both the country and the coal industry. Coal producers continue to develop improved technology for more efficient and cost-effective coal mining and processing. But for controlling transportation costs, coal producers must rely on a delicate balance between product demand, competition among carriers, federal regulation, and a symbiotic relationship with coal transporters. In 1981, 739 Mt (815 million st) of coal were mined in the US. Nearly 90% of this coal was moved via

Jan 10, 1982

By R. A. Haney

The Mine Safety and Health Administration (MSHA) has conducted studies both in coal and non-coal mines to evaluate methods for sampling diesel particulates in underground mines. The agency is investigating size separation techniques to distinguish between diesel particulate and respirable coal mine dust. Additionally, ashing techniques have been used to distinguish diesel particulate from mineral dust in metal and non-metal mines. As part of these studies, personal exposures to diesel particulate for various mining occupations have been measured. This paper describes the measurement techniques and summarizes the exposure levels for various underground mining operations.

Jan 1, 1993

Simulation models were developed at the Julius kruttschnitt Mineral Research Centre to provide accurate estimates of power consumption for a wide range of equipment. With the models, a range of circuits and operating conditions can be compared by simulation for a particular ore type. Accurate models of classification allow for the interaction between classifier efficiency and target product size (e.g., P80 or percent passing 150 /an) to be considered. This paper considers a range of circuit types and overall energy efficiency in the context of case studies where different circuit types were treating similar ore types.

Jan 1, 1999

By Frederik P. Agterberg

During the past 20 years, methods of multivariate statistical analysis have been developed on mainframe computers for the integration of geological, geophysical, geochemical and LANDSAT data in mineral resource appraisal. At present, it is becoming increasingly feasible to perform mathematical image analysis of digitized patterns on microcomputers. This has led us to develop a new method of statistical pattern integration for mineral exploration. In this paper, the new method is used to outline, by means of posterior probabilities, exploration targets within small areas of which the prior probabilities for occurrence of new mineral deposits had been estimated by multivariate analysis.

Jan 1, 1989

By Q. Wu

Neural network methodology is used to predict mean particle size resulting from rock blast fragmentation. A blast data base developed in a previous study is used in the current study. A part of this blast data was used to train a single-hidden layer back propagation neural network model for each of the similarity groups obtained in the same previous study. Levenberg-Marquardt algorithm provided the most stable and efficient training out of the four algorithms evaluated. An extensive analysis was performed using a part of the blast data to estimate the optimum number of units for the hidden layer for each similarity group. The remaining blast data are used to validate the trained neural network models. Capability of the developed neural network models is determined by comparing predictions with measured values and predictions based on one of the most applied fragmentation prediction models appearing in the blasting literature. Prediction capability of the neural network models was found to be strong and better than the existing most applied model. Diversity of the blasts data used is one of the most important aspects of the developed models. The developed neural network models are suitable for practical use at mines.

Jan 1, 2011

By Eung Ha Cho, Olufemi Olajide

A laboratory study of dense-medium cycloning with Redstone seam coal has been conducted. The investigation was performed using a 203 mm (8 inch) Heyl-Patterson dense-medium cyclone. Two underflow orifices of 31.8 mm (1.25 inch) and 44.5 mm (1.75 inch) in diam were used. The effects of feed pressure and particle size were determined on the cycloning performance. In addition, the cyclone performances with coal-rich and refuse-rich samples were also investigated. The results of the experiments were analyzed using basic hydrodynamic principles. The increase in the feed pressure increases the specific gravity of separation (defined as the specific gravity of a particle which has an equal chance of reporting to either the overflow or underfow) for both underfow orifices. The specific gravity of separation increases as the particle size decreases with the smaller underflow orifice. However, an opposite relationship has been observed with the larger under flow orifice. The separation becomes sharper with the smaller under flow orifice than with the larger underflow orifice especially for fine material. Also, the separation becomes sharper with an increased feed pressure for a coal-rich sample. However, this effect is less significant for a refuse-rich sample. This means that a high feed pressure is required for a coal-rich sample to maintain a good separation. It also means that applying a high feed pressure provides a good separation regardless of the type of feed coal in terms of ash content in the solid.

Jan 1, 1990

By Gun Berglund, Eric Forssberg

Sulphide mineral flotation is known to be affected by oxidation-reduction conditions in the pulp, although there is some doubt as to whether it is the oxidizing environment or the type of oxidant which influences flotation. Variations in the oxidizing conditions of the pulp and their subsequent effect on flotation were examined for two types of natural sulphide ore, a galenasphalerite ore and a complex pyrite ore. Different gas mixtures ranging from pure nitrogen to pure oxygen were used to control the oxidizing conditions. Zinc recovery increased with a more oxidizing environment, and nitrogen gas acted almost as a depressant for sphalerite in the flotation of the Pb-Zn ore. For the complex pyrite ore, the selectivity between chalcopyrite and both gangue and pyrite improved when the environment was oxidizing, resulting in higher Cu recovery in the copper rougher concentrate. The use of an oxygen rich flotation gas was found to be a suitable method for changing the oxidizing conditions and improving flotation under controlled conditions. The flotation results were correlated to the oxygen content and the redox potential, parameters which describe the pulp chemistry conditions.

Jan 1, 1989

By J. D. Pitts

Long distance slurry pipeline systems for steam coal, iron concentrates, copper concentrates, and limestone, first used nearly 60 years ago, are now transporting nearly three billion ton-miles annually. At this time a phosphate concentrate pipeline is nearing start-up and systems for transporting coking coal, lead/zinc concentrates, and fly ash are planned. The solids pipeline concept was first patented in the early 1900's and put into practice in the 1950's. Table 1 summarizes the major elements of several presently operating commercial systems. Increased control system sophistication has been accompanied by significant drops in control equipment size and cost, as illustrated by recent cases of pipeline operation with progressively more advanced level of control: 1) The Consolidation Coal (Ohio) and Savage River (Tasmania) iron concentrate pipelines started in 1957 and 1967, respectively, used simple hard-wired control logic. 2) The Black Mesa (Arizona) coal slurry pipeline commissioned in 1971 added a hard- wired programmable logic controller for some of the start-up and shutdown routines. 3) Two years after its start-up in 1974 the Pinto Valley (Arizona) copper concentrate pipeline was tied into the concentrator digital computer system for data logging. 4) The Samarco (Minas Gerais, Brazil) iron concentrate pipeline which came on-line in mid-1977 was the first slurry system to use a dedicated supervisory computer for its control. Communication to remote areas was via micro- wave and buried cable.

Jan 1, 1979

By James C. Franklin

Companies are constantly searching for more effective methods of controlling and reducing costs. In recent years increased emphasis has been placed on cost reporting to the middle manager and down to the first-line foreman because this is the place where the money is really spent. Traditionally, operations management has been relegated to using cost systems designed by financial management for the use of financial management. They reflect the machinery necessary to produce profit and loss statements, and so-called cost reports emanating from these systems frequently have a heavy orientation toward product costing rather than the cost that an individual manager or foreman actually controls. In addition to direct operating costs by function or product type, they often include overhead allocations from local operations as well as from the home office. This type of full-absorption costing has many worthwhile uses but is of little or no use to operations management for cost control purposes. It is particularly discouraging to many supervisors because it includes so many categories of cost over which they have little or no control. It is for this reason that modern, aggressively managed companies are increasingly moving in the direction of responsibility cost reporting. It is the objective of responsibility cost reporting to report only direct operating costs over which the individual manager or foreman has complete control, thus facilitating cost control by fixing responsibility for cost.

Jan 1, 1979

By Stephen P. Harrison

The ventilation of coal mines has long been a major challenge for the mining industry. Prior to the 1969 Health and Safety Act, mine ventilation planning was almost entirely handled by individuals in mine operations and engineering who had extensive practical experience. Their background and expertise was sufficient to deal with existing ventilation problems and planning. A recent decline in the number of qualified individuals combined with more stringent state and federal regulations have necessitated a thorough engineering oriented approach to ventilation in mine planning design. To plan for an existing mine, a thorough ventilation survey must be conducted to determine the capabilities of the existing ventilation network. A ventilation survey also provides considerable useful data for long range planning. Essential information such as friction factors, entry resistance, and potential ventilation problem areas is gained from the survey data. With this information a comprehensive computer analysis can be conducted to evaluate alternative mine plans. This evaluation of mine plans is essential to minimize the number of shafts required while still maintaining the quality of mine ventilation. Using an existing mine as an example, this paper outlines a detailed procedure for organizing, con-ducting, and evaluating a ventilation survey. In addition, specific ventilation problem areas are isolated and alternative methods for their solution are considered. Furthermore, a long range mine plan is evaluated and the most feasible variation of the plan is selected.

Jan 1, 1980

By E. J. Beckman, R. M. Enick, C. Powell

Liquid carbon dioxide can be used as a replacement for organic solvents in the extraction of anionic platinum group metal complexes from an aqueous phase. However, because conventional extractant-metal complexes are not soluble in liquid carbon dioxide, this can be achieved only if highly carbon dioxide-soluble extractants are developed. For example, trioctylamine-gold chloride is not soluble in liquid carbon dioxide, although trioctylamine is CO2 soluble. The novel CO2-soluble extractants presented in this paper have a CO2-philic fluorinated tail to enhance solubility and a conventional amine head group for extraction of metals. Both the extractant and the extractant-metal complex are soluble at ambient temperature at pressures from 7 to 35 MPa. Efficiency factors as high as 2.23 have been measured using 1,1,2-trichlorotrifluoroethane (TCTFE), a low pressure screening liquid for carbon dioxide, indicating that these compounds will strongly bind the metal chloride. For example, 84% of Pt-chloride was extracted into TCTFE using a 3.5:1 ratio of a double¬tailed fluoroalkyl amine extractant: metal chloride. An 88% recovery of Pt-chloride into high-pressure liquid carbon dioxide was achieved using the same extractant at a 3.5:1 ratio. Therefore, it appears possible to replace organic solvents with liquid carbon dioxide during the extraction of platinum chlorides if highly carbon dioxide-soluble extractants agents are employed.

Jan 1, 2002

By Bruce E. Holbein, Dennis K. Kidby, Ann L. Huber

World gold production figures and the processes used for gold production indicate a high dependence on both cyanide leaching and carbon adsorption metallurgies. Problems associated with the use of carbon in the treatment of refractory ores as well as economic and environmental considerations associated with the use of cyanide point to the advantages that can be realized through the use of more efficient gold adsorption media and with cyanide recovery. We have developed a process termed AurosaveTM-1 which provides a number of advantages through the use of a new synthetic robust gold adsorption medium, termed Vitrokele TM V-911. This process allows further recovery of gold from a variety of ores and allows for a simplified process for use not involving thermal regeneration or high pressure elution. We have also developed a cyanide recovery process termed Cyanosave ™ which uses Vitrokele TM V-911 and allows efficient recovery of cyanides from decants or tailings and re-use of recovered cyanide. This obviates the high chemical expenses for cyanide destruction where environmental issues require such water and tailings management.

Jan 1, 1998

By S. A. Braley

Water is our most important natural resource, for without it there is no life. It is also the principal natural resource for all manufacturing processes, in particular for the development of power. For these reasons it is essential that water be protected and conserved, with the realization that its quality 18 as important as the water itself. A significant factor in the quality of ground water is the mining of coal -- that other main ingredient of Power. In the mining of coal it is necessary to disturb the geological strata overlying or adjacent to the coal seam. This procedure not only releases water from water-bearing strata or underground aquifers but also exposes other minerals which eventually become the source of pollution or deterioration of the released water as well as of the surface stream into which It is discharged It is then evident that in attempting to utilize one essential natural resource there is degradation of the quality of the other. Many selfishly assume that the principal function of a stream is fishing and recreation, but the real function is the support of industry and agriculture upon which civilization is dependent.

Jan 1, 1959

By W. D. Gould, . W. Koren, P. Bedard, P .. B. Marchant

Ammonia and nitrate in metallurgical operations arise from several sources: (1) the use of ammonium nitrate based explosives, e.g. ANFO; (2) the use of cyanide for gold extraction which is degraded to ammonia by most cyanide destruction techniques; and (3) the use of nitrogenous reagents in the mill for neutralisation, flotation and extraction. The concentrations of ammonia and nitrate in effluents vary from 10-50 ppm and 25-300 ppm respectjvely. A number of environmental problems are associated with both ammonia and nitrate. Both of these forms of nitrogen can contribute to the eutrophication of receiving waters. Ammonia and organic nitrogen can also cause high dissolved oxygen demands in receiving waters. Ammonia is also toxic to fish, particularly at elevated pH values. Several methods are in use for the removal of ammonia and nitrate from municipal wastewater, industrial effluents and agricultural runoff. To date, no treatment systems have been developed specifically for the removal of nitrogen from mine and mill effluents. This paper will report on some removal techniques that have been tested using actual and synthetic mine effluents.

Jan 1, 1993