Search Documents

By G. Barbery

A review is given of the present applications of random sets and integral geometry in fragmentation and liberation models of ores and minerals. Although attempts have ben made in the past to apply such mathematical techniques to the comminution of solids, it is shown that it would not result in major progress. In liberation modelling, it is demonstrated that the approach can lead to fruitful results. Following a recent paper by Davy (1984), a model of liberation prediction is developped, which can be calibrated far ore texture and breakage using image analyzers. The model is demonstrated for the case of a Poisson polyhedra ore texture and monodisperse fragment size. The model enables to predict the complete composite particle distribution, and is thus valuable for integration of ore breakage models with minerals separation models.

Jan 1, 1985

By Robert D. Schmidt

The US Bureau of Mines is cooperating with Cyprus Mineral Park Mining Co., Columbia University, and the US Geological Survey in investigating the feasibility of applying in situ leach mining methods to fracture-hosted, supergene copper sulfide (chalcocite) ores. This paper presents the initial findings of mineralogical, hydrogeological, and geochemical characterization studies conducted at the Mineral Park mine, located in the Wallapai mining district of northern Arizona. A design for in situ leaching is proposed that would minimize the need for blasting prior to leaching, and would enable economical development of deep reserves at the Mineral Park mine. The in situ leaching design would also reduce the potential for long term acid rock drainage.

Jan 1, 1995

By G. A. Parkison

The sequential copper analysis method is a particularly useful technique to semi-quantitatively define the geologic, mineralogic, and metallurgical types and zonations commonly associated with porphyry-type copper deposits. The method is based on the partial dissolution behavior displayed by the prevalent copper minerals malachite, chrysocolla, chalcocite, and chalcopyrite to solutions containing sulfuric acid and sodium cyanide. Results from sequential analyses of the sample and analytical residue using sulfuric acid followed by sodium cyanide and then aqua regia solutions when compared with conventional total copper analyses can determine the amounts of leachable oxide minerals, leachable secondary sulfide minerals, and primary copper minerals, respectively. Sequential assay analytical results and interpretation are presented for copper deposits in Chile, Mexico, and the United States.

Jan 1, 1995

By C. H. Stephenson, Z. White

This paper presents the design approach case study for incorporating a Technogrid® conveyance End-of-wind arresting system within the new South32 Hermosa headframe. Focus is placed on energy absorption requirements, structural integration, and mounting details tailored to the geometry and operational constraints of the headframe. Key considerations include arresting forces, load path continuity, and connection design to ensure reliability and maintainability. The paper also discusses coordination with other headframe systems and the iterative design process used to meet safety standards and client objectives.

Feb 22, 2026

By S. Philipp

This paper describes several variants of placement and design, from a technical and economic point of view, of shafts, ore bunkers and drifts near shafts of a Russian potash mine. Advantages and disadvantages of the position of different workings are shown as well as an analysis of stratigraphic and geological layers and their use for excavating pit bottoms, haulage drifts and bunker installations. The potash mine consists of two hoisting shafts and one service shaft. The hoisting capacity of one of these skip shafts is planned to be approx. 7 Million tons of crude potash salt per year. Both shafts together will have a hoisting volume of about 14 Million tons. When the mine will increase their highest level of production, it will be one of the biggest potash mines in the world. The skips, the hoist drives and the bunker near the shaft will belong to the largest ones worldwide, too. This paper specifies the features of such a double skip shaft pit in detail and demonstrates problems, which depend on the fact that the pit bottom is in a depth of nearly 1200 m.

Feb 23, 2014

By Sebastian Avalos, Julian M. Ortiz, Willy Kracht

Semi-autogenous grinding mills play a critical role in the processing stage of many mining operations. They are also one of the most intensive energy consumers of the entire process. Current forecasting techniques of energy consumption base their inferences on feeding ore mineralogical features, SAG dimensions, and operational variables. Experts recognize their capabilities to provide adequate guidelines but also their lack of accuracy when real-time forecasting is desired. As an alternative, we propose the use of real-time operational variables (feed tonnage, bearing pressure, and spindle speed) to forecast the upcoming energy consumption via machine learning and deep learning techniques. Several predictive methods were studied: polynomial regression, k-nearest neighbor, support vector machine, multilayer perceptron, long short-term memory, and gated recurrent units. A step-by-step workflow on how to deal with real datasets, and how to find optimum models and final model selection is presented. In particular, recurrent neural networks achieved the best forecasting metrics in the energy consumption prediction task. The workflow has the potential of being extended to any other temporal and multivariate mineral processing datasets.

Jun 16, 2020

By D. R. Taylor

The use of clay granules as carriers for pesticides dates from the early 1940's and by the present day represents a business conservatively estimated at between 200 -300 thousand tons / year in the U.S. alone. Aside from economic and specific target pest efficacy advantages, the use of clay granules as pesticide carriers also delivers a number of environmental benefits which will be reviewed. Topics to be discussed will include: I) drift control (versus liquid sprays), 2) mobility (in the environment), 3) worker safety, and 4) transportation (spill) safety.

Jan 1, 1999

By R. Mensah-Biney

The adsorption of gold-thiourea complex onto a cation exchange resin, Amberlite 252, has been evaluated in a batch stirred reactor. The observed non equilibrium saturation capacity was 3.20 meg Au/g dry resin (620 kg/t) whereas the equilibrium ion exchange capacity was only 0.53 meq/g (103 kg/t). The enthalpy of adsorption was 4 -25 kJ/mole under equilibrium conditions and increased to 20-200 kJ/mole under non equilibrium conditions. Under non equilibrium conditions, the adsorption capacity of the resin decreased with increasing temperature and increasing thiourea concentration and increased with increasing gold concentration. This dependence of adsorption capacity on thiourea concentration and temperature may be a useful tool for elution of gold from the loaded resin. Scanning electron microscopy revealed evidence of deposition of elemental gold on the loaded resin under non equilibrium conditions. The proposed mechanism for "adsorption" of gold-thiourea complex onto this cation exchange resin consists of an ion exchange reaction followed by a reduction of the exchanged gold complex to elemental gold on the surface of the resin.

Jan 1, 1997

By Arthur G. Strassburger

INTRODUCTION High in the Sierra Nevada Mountains of California, some 50 airline miles (80 km) northeast of Fresno, and near the John Muir Wilderness and Kings Canyon National Park, a large underground hydroelectric project is under construction. Pacific Gas & Electric (PG&E) Company's 1,125 MW Helms Pumped Storage Project exhibits a number of impressive statistics, unusual features, and other characteristics of interest to the tunneling or power plant designer and construction contractor. The most significant underground facilities include almost 20,000 ft (6,096 m) of 27-ft (8.2 m) diam concrete-lined pressure tunnel; 3,700 ft (1,128 m) of access tunnel; 1,600 ft (488 m) of steel-lined high-pressure conduit, 2 major underground chambers more than 1,000 ft (305 m) below ground; 3 deep vertical shafts, and one steep inclined shaft. Maximum static pressures within the conduits range from 200 ft (61 m) to 1,744 ft (532 m), with hydraulic transients that increase pressure to 2,500 ft (762 m). The purpose of these underground works is to provide 475,000 hp (354,350 KW) of water power to each of the 3 reversible pump-turbines, each connected to a 375 MW generator motor. The units, rated at 1,744 ft (532 m) maximum static head, are among the world's front-runners, considering the size-head combination. The Helms Project develops the existing power drop between two of PG&E's reservoirs, Courtright Lake and Lake Wishon. These reservoirs are retained by two concrete-faced rockfill dams completed in 1958, each storing approximately 125,000 acre ft (154 x 106 m3) of water. Although the project is intended to operate on a typical

Jan 1, 1981

By T. Guler

Turkey has important celestite reserves in Sivas. These reserves have gypsum and/or calcite as gangue minerals. Celestite-calcite ore cannot be concentrated by gravity methods due to the low efficiency of gravity methods in fine sizes. Research was tried to concentrate celestite to a market grade by flotation. Parameters such as pH, particle size, dosage and types of collector and depressant were examined. Cyanamid A-845 and Na-oleate combination as collector, sodium silicate as depressant, and Aerofroth-65 as frother were found as the optimum flotation reagents. By applying 3-stage cleaning, a concentrate assaying 95,34 % SrS04 was obtained with 84,93 % recovery.

Jan 1, 1999

Over the years, numerous studies have been conducted to characterize the floatability of coal pyrite. Unfortunately, many of the results obtained using isolated samples of coal pyrite are not directly applicable to actual coal flotation systems where liberation and entrainment may be the major factors affecting pyrite rejection. In this paper, the association of pyrite with other coal constituents is investigated, and the data are presented for feed and product streams obtained from release analysis tests. Release analysis is used to minimize the effects of entrainment. Particle distributions for each stream are presented as functions of size and composition in order to discern the behavior of free and composite particles.

Jan 1, 1992

By T. A. Toney

With new lightweight designs, spirals have become standard equipment in coal preparation plants worldwide. To their credit, spirals typically show very low coal losses to the refuse stream under most operating conditions. However, spirals do tend to separate at cut points in excess of 1.80 S.G. Attempts to obtain lower cut points have typically resulted in coal losses to middlings. Middlings retreatment with secondary spirals is therefore becoming common place. Other forms of retreatment with water-only cyclones, hydrosizers, and recirculation have been attempted with some success. This paper reports on a novel (Patent Applied For) approach to retreating spiral middlings m a heavy-media-cyclone circuit.

Jan 1, 1998

By K. A. Natarajan

The relative significance of corrosive and erosive wear in magnetic taconite grinding is examined. The influence of different types of aeration, namely, nitrogen, air and oxygen on ball war was established for mild steel and high carbon low alloy steel balls. Ball wear data from dry and wet grinding tests are compared with those obtained in the presence of an organic solvent that does not promote electrochemical corrosion. 'Marked ball grinding, tests along with electrochemical measurements involving ball material and magnetite electrodes indicate that contribution from oxygen towards wear (corrosive wear) is relatively small and abrasive wear appears to be significant. Rheological properties of the slurry-appear to have an important bearing on the abrasive wear of grinding balls.

Jan 1, 1983

By Nikhil Dhawan, Ashwini Kumar, Yogendra Pratap, Himanshu Tanvar

India does not possess any soluble potash reserves and depends completely on imports. In this study, an attempt has been made to recover potash (K) values from the mica sample employing thermal and mechanical routes followed by leaching. Direct leaching of mica in different lixiviants is found to be ineffective with very low K-dissolution (1–5%). Heat treatment with different fluxes, such as NaCl, NaOH, and CaCl2, is carried out and almost 85% K-values are recovered. Mechanical activation of mica and with different calcium additives is carried out to recover potash values. K is recovered in leach solution in the form of soluble salts, such as K2CO3, K2SO4, and KOH, and leach residue consists mainly of calcium-alumino-silicates. Using mechanical activation with flux, it is possible to recover >95% K-values from mica sample. Mechanical activation with calcium-based flux is found sustainable in the recovery of K-values from mica.

By R. M. Schuster

This study attempts to compare the costs of transporting coarse coal by pipeline, versus the more conventional use of belt conveyors. Hydraulic conveying of crushed (not pulverized) coal has not had widespread commercial acceptance. However, there is little doubt that the technology is available, so that, should this method be proven economical for a given application, implementation of this technology will become more acceptable. Hydraulic transport by pipeline between the mine stockpile and the coal preparation plant, for distances normally considered practical for an overland belt conveyor, should be an ideal application. In this application there is no need for dewatering facilities at the receiving end of the pipeline, because, the receiving screens at the plant serve this purpose. Further, clarified water from the preparation plant can be recirculated back to the mine, a plus for water resource and environmental considerations.

Jan 1, 1982

By Jun Yuan

Kaolin clays from five different commercial deposits in Georgia were studied to understand the variations of zeta potential and related fundamental properties. The results suggest that higher negative zeta potential is related to exchangeable or soluble calcium ions in the clays.

Jan 1, 1997

The US economy grew at a rate of 4% in 1994 and the gross domestic product rose to $6.74 trillion. With 261 million people - 605,000 in mining, including petroleum -the United States has l 10 million dwelling units and 200 million licensed motor vehicles. New private housing units authorized in 1994 rose 14% to 1.4 million units. New car production rose 11 % to 6.6 million units, while truck and bus production rose 30% to 5.2 million units. The inflation rate was less than 3% and the prime rate of interest averaged 7.15%. The producer price index (1982 = 100) for fuels and related products and power was down 4% to 78, while metals and metal products rose 5% to 125. Chemicals and allied products rose 3% to 132, and non-metallic mineral products rose 3% to 124. The merchandise trade deficit rose 25% to $166 billion. Disorder in the former Soviet Union led to substantial dumping of mineral materials. With vast mineral resources, the former Soviet Union land area totaled 22.4 million km2 (8.6 million sq miles). In comparison, the North Ameri¬can Free Trade Agreement (NAFTA) area (United States, Canada and Mexico) totals 21.4 million km2 (8.3 million sq miles).

Jan 1, 1995

High pressure grinding rolls have found widespread acceptance for cement processing, and are now making their debut in the metalliferous minerals industry. Significant energy and wear material savings appear achievable in many applications. This paper re- views the technical literature on this important, emerging technology.

Jan 1, 1997

The dissolution kinetics of gold in iodide solutions with oxygen in an autoclave was investigated. The leaching process was described by a gas-liquid-solid heterogeneous reaction. The effect of stirring speed, temperature, partial pressure of oxygen, and concentration of lixiviants on the overall leaching rate was investigated. It was found that the dissolution of gold was limited by a heterogeneous chemical reaction. The apparent activation energy was measured to be 34.7-54.3 kJ/mol under the conditions studied. Experimental findings were in good agreement with the kinetic model proposed.

Jan 1, 1996

By W. C. Hirt

Selective flocculation was used to produce superclean zinc concentrate with minimized silica contamination. Research was carried out on a flotation concentrate from the Jersey Miniere Zinc Company (JMZ) in Gordonsville, Tennessee. The material was first dispersed with sodium silicate and then causticized tapioca starch was used to selectively flocculate the sphalerite, leaving the silica in suspension. This technique has been applied commercially to iron ore beneficiation but has never been used for processing zinc. The feed material assayed 0.45% Si02. Use of 0.56 kg/tonne (1.13 lb/st) of sodium silicate and 0.070 kg/tonne (0.141 lb/st) of causticized tapioca starch resulted in 98.2% zinc recovery in a purified zinc concentrate assaying 66.0% Zn and 0.24% silica. The present target level for silica contamination in JMZ zinc concentrates is 0.3% Si02. This work has shown that selective flocculation offers a potential method for cleaning flotation concentrates, particularly where low silica products are required.

Jan 1, 1993