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By Bob Clayton, David Readett

Jameson Cell technology has found applications in the cleaning of entrained material in copper Solvent Extraction - Electrowin plants. The materials involved are largely organic substances that have not been totally removed prior to treatment of the rich electrolyte in the tank house. This paper discusses the recovery of the entrained organics in the rich electrolyte streams at Phelps Dodge Morenci in Arizona. Mount Isa Mines in Queensland. Australia and the Olympic Dam Operations in South Australia. The paper details the design, performance, the feed and product characteristics, capacity and operation. In one operation the entrained material has been observed to include crud that has been formed in the SX train. The mechanism of recovery is also discussed.

Jan 1, 1993

By George S. Koch

Today, after about 30 years of development, computer-based analysis of geoscience data has reached a mature phase. From the tentative early beginnings recorded in the proceedings of the APCOM meetings, geoscientists are now able to emphasize the need for both pertinent mathematical/statistical models and computer hardware and software. From those models that are well understood in the disciplines of statistics and mathematics and for which effective computational methods are available, practitioners select and develop methodology for their particular purposes. Computer hardware is typically assembled from off-the- shelf components now readily available, with particular emphasis, whenever feasible, on microcomputers for reasons of economy and control by the scientific or engineering user rather than by a bureaucratic computer center. Computer software may be written by the user in high level languages such as Pascal, FORTRAN, or LISP. However, more often today geoscientists use routines available in spreadsheets, data bases, or statistical packages. In so doing, they save time and, programming costs and take advantage of routines written and maintained by large, well- established organizations, while losing the flexibility in specifying exact input/output afforded by writing in a high level language.

Jan 1, 1989

By K. N. Han

Copper and nickel are extracted from their elemental state, complex sulfides, ores, and other materials such as scrap by leaching them with a solution containing halogen salts - bromine/bromide, and/or iodide/iodine, oxygen and sodium or potassium nitrate. This US patented process is extremely effective yielding 98% recovery in15 minutes for the treatment of chalcopyrite and pentlandite in an autoclave at a temperature of 100°C - 150°C.

Jan 1, 2003

By S. K. Kawatra, T. C. Eisele

A horizontal-baffle arrangement has been developed to prevent excessive axial mixing in flotation columns. These baffles have been shown in previous work to improve the grade/recovery performance of both a laboratory-scale column and a pilot-scale column (Kawatra and Eisele. 1993). In this paper, results are given for continuous on-line operation of the pilot-scale baffled column in a commercial coal- cleaning plant. These results show its ability to operate for extended periods without plugging, to produce a consistent-quality product even while the feed quality was fluctuating, and to remove much of the pyritic sulfur from the coal.

Jan 1, 1995

By E. F. Divers, R. A. Jankowski

In response to a request from the Mine Safety and Health Administration (MSHA), the US Bureau of Mines completed a respirable dust survey of 18 US coal preparation plants. Of these, three were essentially free of dust problems. Respirable dust exposure to workers in the remaining plants depended on the time spent in the dusty areas. In five of the plants surveyed, Bureau tests showed that in some areas worker exposures could exceed Federal dust limits in less than two hours. Cooperative studies were arranged with coal preparation plants using three different dust control techniques. These included a standard baghouse-type dust collector, two types of scrubbers, and an electrostatic precipitator. Results of these evaluations are presented. Various types of ventilation systems used during summer and winter conditions were also evaluated. Results showed that appropriate ventilation can provide a highly cost-effective method for controlling coal preparation plant dust.

Jan 1, 1987

By Warwick Hoffmann, Robin Batterham, David Conochie

CRA has been actively involved in developing a bacterial oxidation process for the treatment of low grade, refractory gold resources. Success in this application is dependant on the design of large, energy efficient reactors. It was identified at an early stage, that the conventional, bottom sparged bioreactor is inherently inefficient because air must be compressed to a pressure above that at the bottom of the tank. This inefficiency increases as the size of the reactor increases. CRA has developed a novel approach to the aeration problem. In this, venturi aeration is used to aspirate air into a liquor stream. The stream is then reintroduced at the top of a draft tube bioreactor. The advantages found with this technique include · low energy requirements and high oxygen utilisations. From results at the 30 m3 scale, we predict an energy usage of -500 kWh/t sulphur oxidised at a scale of 1000 m3.

Jan 1, 1993

By Y. A. Attia, D. K. Sengupta, H. A. Hamza

Increased recycling of waste paper has been emphasized in recent years in both the United States and Canada for environmental and economic reasons. Removal of ink particles from waste paper pulp is therefore necessary. One of the most promising methods for ink removal is froth flotation. This study investigated the feasibility of a simplified flotation scheme and found that about 90% to 92% ink removal can be achieved. Also, a 95% to 97% ink removal is achievable if a hydrophobic polymer is used ahead of the flotation stage. Clean paper pulp recovery was over 90%. The effects of pulping pH, flotation pH and concentrations of flotation and polymeric reagents are discussed in the paper.

Jan 1, 1995

By D. Robert Weir, Roman M. G. S. Berezowsky

Pressure oxidation of gold containing concentrates and ores is an effective pre- treatment for liberating refractory gold. This is particularly true when an appreciable portion of the gold is associated with sulphides and is not amenable to conventional cyanidation. A brief review of the literature on the pressure oxidation of refractory gold materials is presented. The chemistry of the aqueous oxidation of arsenopyrite and pyrite is discussed. Data obtained on the pressure oxidation and subsequent cyanidation of concentrates and ores tested at the Sherritt Research Centre are also presented.

Jan 1, 1984

By Michael Drozd

Introduction Flotation is a recovery process that utilizes natural or chemically-introduced hydrophobicity of minerals to separate ore from gangue by attaching the ore particles to bubbles. Flotation has been known since 1906, when it was patented by E. L. Sulman, H. G. K. Pickard and John Ballot. Flotation's first documented plant use was in 1911, when it was used on gravity tailings from a zinc plant. Cyanide leaching was first patented in 1887. Most early precious metals flotation was linked to lead or copper concentrates. Most precious metal flotation is linked to sulfide recovery and utilizes such reagents as xanthates, dithiophosphates and thiocarbanilides. But the involvement of flotation in precious metals recovery does not have to be limited to active flotation of the gold and silver bearing minerals. Flotation can be used to remove interfering minerals, such as carbon, or cyanicides, such as copper, arsenic bearing minerals or other cyanide complexing minerals. Cyanide Leaching The use of cyanide to recover precious metals is the backbone of the industry. The various recovery processes that use cyanide are: 1. Leaching-Counter Current Decantation(CCD) Merrill-Crowe 2. Carbon-in-pulp (CIP) 3. Carbon-in-leach (CIL) 4. Vat leaching 5. Heap leaching These processes are selected depending on ore grade, ore leaching characteristics, reserve size and capital limitations. Ore grade is used as the first criteria to determine the type of cyanide plant required. However, the reserve size can determine whether a ground ore alternative is used. The ore leaching characteristics may indicate that the higher recovery, associated with a process that employs grinding, is the only economic recovery alternative. There are some extremely large leaching plants with grades that would be non-economic for some existing heap leach plants. Many factors, such as strip ratios, metal recovery and reserve size, determine what the ultimate plant design will be. The exact processing scheme that is used, is a multifaceted decision matrix, which gives the process metallurgist some job security. Precious Metal Recovery Using Flotation Flotation recovery can conceivably be used on any ore that has been ground. Many operations utilize gravity separation on the ore to remove native gold from the ore prior to sending it to cyanide leaching. On certain ores, where the gold is in visible nuggets or particles, this processing alternative is advantageous because the native gold cyanide recovery is

Jan 1, 1993

By L. T. Larson

Nothing in Turkey is simple. Its his¬tory is long and convoluted, its culture fascinating, its metallogeny diverse, and its geology very complex. This article will focus on the geology of western Anatolia and the precious metals poten¬tial of this third of Turkey. Any gold produced by mines in Tur¬key since the early 1900s has been a by-product of the mining for other met¬als, such as copper from the massive sulfide deposits of the Pontics. Archaeological records, however, prove that gold was mined from the Pactolus (present day Gediz) River and refined by Croesus at Sardis in about 550 BC. Other records and legends make it possible that gold was mined before 1200 BC for the Homeric City of Troy (Priams treasure?) about 25 km (15 miles) east of Canakkale at Mad¬endag and Kartaldag. A final legend of antiquity suggesting gold in what is now Turkey relates to King Midas. And, indeed, the city-state belonging to a king of that name has been recognized near the city of Eskise¬hir. More recently, precious metals have been mined at Madendag-Kartaldag in the late 1800s. Arapdag, near Izmir, remains the only "authenticated" epith¬ermal precious metal deposit in Turkey (Mosier et al., 1985). With this spotty record, why the sud¬den interest shown by at least five Euro¬pean-based, three or four US-based, and several other international mining firms and their Turkish subsidiaries? Like other aspects of Turkey, the complete answer is not simple but, reduced to its basics, has three parts. Turkey, relative to many developing nations, has a stable, democratic form of government (although it also has a for¬midable bureaucracy) whose currency exchange rate is premised on the US dollar. New laws promulgated since 1983 have opened the country and welcomed foreign investment. Some have even provided investment incentives. The Mining Law of August 1985 made sweeping reforms of the old land tenure system. This law made it possible for a foreign-based company to have a wholly-owned Turkish subsidiary en¬gaged in mining. Equally important is the belated recognition that western Anatolia, while geologically compli¬cated, is today basically a province Neogene extensional tectonics having many of the geologic attributes of the leading gold producing province of the US - the Basin and the Range. Geologic rationale for precious metals exploration Tectonic/lithologic framework: Alle¬gorically and simplistically, Anatolia during early Neogene (middle Miocene) can be likened to a tube of toothpaste with the cap off. It is squeezed in the vise formed by the Arabian plate mi¬grating north toward the southwest end of a stable Asian platform. The "tube" was compressed. It could not expand to the east because it was sealed by what is now southern Russia and Iran. The filling of the tube escaped to the west, in the direction in which the cap was miss¬ing (Fig. 1). So developed during the middle to late Miocene the western-most struc¬tural province of Anatolia. This was done by a process aptly termed tectonic "escape" by Sengor et al (1985). This province is dominated by exten¬sional tectonics much like the Basin and Range of the western US and has an estimated extension of between 30% and 50%. The most striking manifesta¬tion of this extension is the 10 to 11 major east-west trending grabens (Ge¬diz, Buyuk Mendares, Kocuk Mendares, etc.) and intervening horsts, although a much greater number of smaller, gener¬ally northeast-striking grabens and half

Jan 1, 1989

By G. Gaidajis

Sea water samples collected from coastal waters in the vicinity of the Stratoni mining operations, in North-Aegean Sea were analysed for dissolved metals and elements. The maximum concentrations observed were one to three orders of magnitude lower than the environmental limit which coincides with the quality of sea waters suitable for swimming purposes. The quality of the coastal sea waters are affected by the natural mineralization of the area and the urban activities drained through local small rivers, the past mining activities present in the sea bottom sediments in the form of disposed tailings, and finally by the presence of the adjacent Mill-Flotation Plant. The relative importance of the treated final effluents discharged from the mining operations is considered to be insignificant.

Jan 1, 2006

By Merwin Bernstein

Peru has been an important source of metals since Aug. 29, 1533. On that day Francisco Pizarro took charge of the 24 t (772,000 oz) of gold and silver that constituted Atahualpa’s ransom. At today’s prices, the value of that booty ranges between $100 and $150 million, depending on the proportion of gold to silver. Since then, Peru’s silver and gold production has been legendary. Current mine production Most of Peru’s metals are mined from the Andes Mountains and its foot-hills. The Andes run the length of the country parallel to the Pacific coastline from Ecuador to Chile, a distance of nearly 3000 km (I 875 miles). They are about 300 km (187 miles) wide and much of the range is more than 3000 m (9900 ft) in elevation. High plateaus (altiplanos) occupy a large part of the range. Both flanks are rutted by large valleys and canyons. Many of these peaks are prodigious. which make road building expensive and adds to the cost of mining.

Jan 1, 1993

By G. Danko

Ventilation and refrigeration for mine climate modification, contributes significantly to the operating costs of a deep hot mine. Mine climate simulation programs can be used to minimize the impact of these costs. There are several computer codes available including CLIMSIM?, to assist in this work. Whichever simulation program is used, it is the mine ventilation engineer who must supply the input data. This paper raises and answers the following question, namely: what accuracy is required of the basic input parameters, in order for a certain precision to be obtained in the predicted air temperatures? In the first part of the paper a new approach is described to estimate the dry and wet bulb temperature of the airflow, either in a dry or wet roadway. The calculation procedure allows an arbitrary temperature change with time, using Duhamel's superposition solution. Matrix-vector representation is applied to simplify the computational structure. In the second part of the paper the sensitivities of the dry and wet bulb air temperatures are analyzed to the changes of the rock thermo-physical properties, the heat transfer coefficient and the wetness factor.

Jan 1, 1988

By Zhang Zhitie

The limitations in mechanism research of mineral comminution in the past and the basic features of the comminution process have been analyzed. Two kinds of catastrophe model, i.e., cusp model and swallowtail one in the mineral comminution have been put forward. The dissipative structure of the mineral comminution: entropy production rate, extra entropy, extra entropy production and system stability has been discussed. The physical nature of the behavior that an old structure was destroyed and a new one was produced in the mineral comminution process has been brought to light.

Jan 1, 1995

By Lynn B. Hales, Randy A. Ynchausti

Object-oriented technologies have been developed to more closely model the way we think about the world and our natural approach to solving problems. Higher levels of abstraction, generalization and classification are benefits of an object-oriented approach. Object-oriented programming, design, and expert systems are part of this technology which is shaping the future of real-time supervisory control. Goals of real-time supervisory control systems include: minimizing variations in process operations, improving efficiency, maximizing production, and implementing procedures for starting and stopping the process. Incorporating object-oriented technology in design, development and implementation of real-time supervisory control systems provides new opportunities for these tasks. This paper discusses some of the opportunities and challenges of implementing real- time supervisory control using an object-oriented expert system for a rougher flotation circuit

Jan 1, 1993

By J. S. Gardner, K. E. Houston, A. Campoli

INTRODUCTION Disposal of coal refuse is a costly and challenging problem facing the coal industry today. After the Martin County Coal Company slurry spill and the subsequent regulatory changes state and federal agencies are now beginning to require companies to justify new slurry impoundments. The authors have performed an analysis of different means of disposing of coal refuse for a major coal producing company located in the eastern Kentucky coalfields (the name of which will be withheld for the purpose of this paper). The company’s existing slurry impoundment is nearing its maximum permitted elevation and also an elevation where it may come in contact with abandoned underground workings. Due to the increased concern with underground mine works near slurry impoundments, additional consideration was given to raising the existing impoundment. Several other alternatives were evaluated, including but not limited to raising the existing impoundment, constructing a new slurry impoundment, constructing slurry cells, belt presses and others. This alternatives analysis was performed as part of a Section 404 permit for a valley fill and is currently being reviewed by the U. S. Army Corp of Engineers. All of the known possible alternatives were discussed in detail in the analysis. Due to the findings of the alternatives analysis, the company considers the engineered construction of the proposed impoundment to be the most favorable option of all the other alternatives evaluated, from both an economic and environmental standpoint. ALTERNATIVES EVALUATION FOR COALREFUSE/SLURRY DISPOSAL Background The company currently operates several deep mines and employ over 300 people and produces over 3.9 clean Mt/a (4 million stpy) of high quality, low sulfur coal. Currently, coarse refuse is belted to a valley fill, while, fine refuse is pumped to the existing impoundment. Coarse refuse is trucked to the existing impoundment as needed for construction purposes. The average recovery is approximately 50%; therefore, over 3.9 Mt/a (4 million stpy) of coal refuse must also be separated and placed.

Jan 1, 2003

By Ronald D. Hill

Acid mine drainage is the result of the oxidation of pyrite and similar iron sulfide material and the release of iron and sulfuric acid into the environment. In addition to the acid water flowing from underground and surface mines, spoil materials in surface mines are acidic and will not support good vegetative growth; thus erosion is a major problem. Lime and limestone are the major neutralizing agents used to treat these acidic conditions. Lime is the reagent preferred by industry for treating acid discharges, although a few companies use limestone. Agricultural lime- stone is used to "sweeten" acid spoils.

Jan 1, 1974

By S. Yang

Based on an analysis of the features found in Chinese surface coal-mining areas, including areas that have already been developed and areas that are in the process of being developed, this paper discusses some rational coal-haulage systems. An optimal decision-making model, which includes a geological model, a mining model and an economic estima¬tion model, was developed for the selection of a coal-haulage system. A case study is presented.

Jan 1, 2000

By Daniel W. Kappes

Until recently, the general expectation among mining compa­nies and financial analysts has been that the price of gold would remain on a generally upward slope. The recent drop in the price of gold has caused many people to re-think the issue. Of course, the price of gold is singularly difficult to predict, so it is difficult to tell which concept is correct. In the present financial situation, however, many junior gold companies are faced with the reality that money is hard to raise, and many senior gold companies find that they are facing a period of corporate losses even though they own solidly producing mines, As engineering consultants, Kappes, Cassiday has recently received several requests to review conventional milling projects to see if heap leaching is a more viable option. In regard to straight financial criteria such as return on investment and net present value, the question is usually fairly easy to answer. However, corporate decisions must often be based on less definable criteria. For instance, new stock issues tend to be more successful if they are larger, which tends to favor milling operations over heap leaches. The corporate issues are often subjective and difficult to generalize about, so I will con­centrate in this paper on a few financial concepts.

Jan 1, 1998

By Zhou Aimin, Xie Benxian, Song Chongkai, He Zhexiang, Zhang Changqing

Concrete pump is commonly used to transport paste and high-density backfill over relatively long horizontal distances. However, since the investment in concrete-pump and its operating cost are quite high, the application of paste backfill is limited in China. For seeking an alternative paste backfill technology, squeezed-transport technique and equipment has been developed. The new technology has been adopted at Tonglushan Copper Mine of Daye Nonferrous Metals Corp for overcoming a difficulty of long-distance transportation of high-density cemented tailings fill. It proved to be an alternative paste backfill method with simple backfill system, saving investment and low operating costs.

Jan 1, 2001