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By Numan Elmas

Barite deposits located in Dinek and surrounding region have important economic features with their large reserve capacity for Turkey. The objective of this study is to elucidate geological and depositional characteristics in terms of. site investigation and chemical analysis. In order to do this, geological area of about 300 km2 was examined and detailed geological map was constructed. It was observed that Barite mineralization in these deposits was occurred in carbonate and pelitic rocks of Lower Cambrian-Lower Ordovician. Deposits were exposed to advanced diagenesis regional metamorphism and tectonics that rotated and deformed the barites; therefore, barites shows secondary veins, brecciate and fracturing structure. Even though, a few light isotope values of barites may suggest hydrothermal and exhalative sedimentary characteristics or possible mixing with magmatic fluids, generally heavy isotope values indicate that the sulfate ions were supplied from coeval seawater and, many of sedimentary features and petrological, geochemical characters support dominantly sedimentary origin.

Jan 1, 2005

By Stephen R. La Brooy, Tong Deng, Pritam Singh, David M. Muir, A. J. Monhemius, G. W. Warren, E. Peters

The controlled addition of ammonia to cyanide solutions inhibits the leaching of copper minerals but extracts up to 80% Au using as little as 10% of the cyanide compared with conventional cyanidation of copper-gold ores. The solubility of copper minerals and copper speciation in solution is dependent on NH3, CN-, pH and Eh. Rotating disc and electrochemical studies show that gold is leached by a mixed Cu-CN--NH3 complex with either Cu(II) or O2 as oxidant. This complex is slowly oxidised to CuCN and Cu(OH)2 by air.

Jan 1, 1993

By H. Sis, S. Chander

The pressure filtration behaviors of dispersed and flocculated alumnae slurries at high percent solids were investigated with the objective of determining the effect of surfactant type and concentration on slurry properties. A high-purity alumina powder was used as a model solid. Dispersion of the alumina was controlled by pH and by surfactants that are known to act as electric and steric stabilizers. The effects of both ionic and nonionic sutfactants were investigated. Surface charge measurements of the slurries were carried out by an electrokinetic sonic amplitude (ESA) method to better understand the mechanisms. The effect of surfactant type and concentration on the kinetics of pressure filtration and cake properties are discussed.

Jan 1, 2000

By R. Hogg, M. Polat, S. Chander

A fresh dust generator was designed and built in order to study the agglomeration behavior and other characteristics of freshly generated airborne dust. The size distribution of the freshly generated quartz airborne dust produced by the generator was measured both directly in air and after dispersion in water. It was observed that same dust particles had an apparently coarser size distribution in air than in water, suggesting possible agglomeration of the dust particles. It was also observed that the size distribution obtained by a cascade impactor was very similar to the liquid dispersed size distribution, implying deagglomeration by the impactor. The agglomeration was confirmed by microscopic observations of particles in air and those collected on a microscope slide. The extent of agglomeration played a decisive role on the fraction of the dust actually becoming airborne. It was also found that contamination of the airborne dust by the rolls of the crusher was almost twice as much as that of the product.

Jan 1, 1991

By Robert E. McIvor

The “Functional Performance Equation for Ball Milling” was first presented in 1988. It now has been used successfully in more than a dozen mineral processing plants. This powerful, yet simple tool provides a new level of understanding of closed circuit grinding. It shows how grinding circuit efficiency is in reality comprised of two distinct efficiencies. It demonstrates how circuit production rate is related, collectively, to these two efficiencies, mill energy input, and the grindability of the ore. It links circuit performance to design and operating variables that can be manipulated, and creates an effective strategy for making plant improvements. This paper covers the derivation and industrial validation of this equation. As part of an engineering and management system that also incorporates suitable metrics and process control, other operators can now use this tool to make improvements and to manage the performance of their grinding operations with clarity and confidence.

Jan 1, 2005

By N. Edmonson

During the last 30 years, a dramatic increase in the supply of byproduct sulfur substantially reduced the share of the market held by Frasch-mined (non-by-product) sulfur in North America. Even though Canadian sulfur production is not discretionary, the geographic remoteness from the large US markets and the high transportation costs associated with delivering sulfur to those markets has meant that Canadian producers act like discretionary producers in many important ways. They have effectively replaced the US Frasch producers as the cost-marginal sulfur source to large US markets. Implications of this change in market structure include more volatile sulfur prices and longer sulfur price recessions.

Jan 1, 1997

By G. T. Lineberry, W. J. Wiehagen, L. L. Rethi

This paper discusses a practical method for enhancing the performance of mining work crews. The method, described as the Work Crew Performance Model (WCPM), seeks to define performance variability within similar tasks of an underground work crew. Key components of the WCPM include: •job definition through task analyses, •the ranking of job elements by perceived cost consequence, •observational techniques to establish performance baselines, and •cost linkages between adherence to task procedures and measures of consequence for noncompliance. The components of this model emphasize a reliance on learning from a veteran work force and using that information to reinvest in strategies to enhance safety and efficiency. These strategies are not limited to technological efforts but include consideration of the so-called "soft-skill technologies, " aimed at reducing variability in individual performance and at effecting a continuous improvement in overall system effectiveness.

Jan 1, 1996

By K. Burke, G. Zhan, A. Mayer

A cover with capi1lary barrier effects (CCBE) is being constructed an the AA leach pad at the Barrick Goldstrike mine near Carlin, Nevada. The purpose of the cover is to eliminate/minimize infiltration of meteoric waters into the leach pad. Laboratory and numerical analyses indicate that Carlin Formation siltstone (TCS), a locally available material, has the necessary hydrologic characteristics when placed on the leach pad to act as a CCBE. A pilot study was conducted on a mall-scale test cover placed on the AA leach pad to examine the cover performance under irrigated conditions. The preliminary test results demonstrate that the designed cover is capable of preventing meteoric water infiltration.

Jan 1, 2002

By R. D. Deister

The Buick concentrator represents state-of-the-art technology in automated digital process control operation utilizing a centralized computer. The process control strategies implemented at Buick are no longer new to the industry, but the successful application of these developments is still rather unique in North America. Productivity improvements, determined to be a direct result of the process control developments, are the primary topics of this paper. Emphasis is placed on metallurgical benefits including both lead and zinc recoveries; lead concentrate grade; and reductions realized in reagent consumptions, operating costs, and personnel. A detailed description of the concentrator, along with a history of the process control development and a more in-depth discussion of the control strategies implemented at Buick can be found in the references. (The Buick flowsheet is depicted in Fig. 1).

Jan 1, 1987

By J. D. Miller, P. L. Sibrell

The nature of surface sites for the adsorption of gold from alkaline cyanide solutions has been investigated using samples of synthetic, highly-oriented pyrolytic graphite (HOPG). This HOPG material offers an idealized graphite structure enabling the independent study of the graphitic basal-plane sites and the edges, or defect sites, of the graphitic planes. Radiochemical and X-ray photoelectron spectroscopic experiments independently demonstrated that gold adsorption was much higher on the edges (defects) of the graphite planes than on the planes themselves. These results suggest that site-specific adsorption is prevalent in the adsorption of gold by graphitic carbons (including activated carbon, carbon black and graphite) and that most of the favored sites are at edge defects in the graphite crystal structure.

Jan 1, 1993

By Z. Sartowski, M. J. Pearse

The authors present laboratory and plant results illustrating the benefits to be gained by using chemical additives, namely flocculants and surfactant dewatering aids, in the Bayer process. Advantages of synthetic flocculants over starch are illustrated in terms of more efficient solid/liquid separation in both the initial settling of blow-down slurries and in the CCD wash train. In addition, it is shown that the use of synthetic flocculants considerably reduce the levels of organic contaminants present in the process liquor. Secondly, very significant improvements in moisture removal were obtained by the application of dewatering aids to hydrate filtration/ washing operations.

Jan 1, 1984

By Y. Wang, E. Forssberg

Wet magnetic separation methods for the recovery of hematite and chromite fines and ultrafines were investigated. These methods included wet high-intensity and high-gradient magnetic separation, carrier or "piggy-hack" magnetic separation, magnetic field-induced aggregation and magnetic seeding. This investigation indicated that wet magnetic separation is more efficient for fines and ultrafines. This investigation also indicated that other methods can be used to enhance the particle aggregation and/or the magnetic response. The magnetic behavior of these minerals with respect to the magnetizing field, temperature and particle size is also presented.

Jan 1, 1995

The issues involved in mine closure are usually complex, and the risks are significant. Although environmental risks are paramount, other issues such as safety, community, legal, fiscal and technical factors need to he taken into account. This paper describes a simple empirical model based on the concept of the closure risk factor, which will enable decision-makers to analyze the mine closure risks at any site, regardless of the complexity of the issues and the scale, scope and location of the operation. The model enables all the issues to be captured and their individual and collective risk quantified. A number of case studies in Australia and the Pacific that illustrate the usefillness of the model are presented.

Jan 1, 2002

By D. M. Muir, C. Cao

Many gold ores have copper mineralisation which presents problems in a carbon-in-pulp operation. Various types of copper-gold ores and ways of tackling the problem are discussed. In some cases copper and gold can be upgraded to a concentrate by flotation; otherwise, copper or gold can be selectively leached. When both copper and gold cyanide are present in solution, it is possible to minimise copper loading onto carbon or to selectively strip the copper from the carbon. Alternative leach solutions like thiourea and bromine are discussed and results obtained with the ammonia/cyanide system are presented in the light of our present understanding of the chemistry involved.

Jan 1, 1989

An information system (I/S) plan is a means for establishing and communicating the direction the organization intends to take to provide the information required for achievement of organizational goals and objectives. The rapid advancements in information technology, the increasing complexity of systems, and the growing dependence of mining companies on these information systems have emphasized the need for more comprehensive I/S planning. This subsection explores this need, the role I/S planning can play within a mining company, and finally describes a methodology for development of an I/S plan.

Jan 1, 1979

The Peruvian mining industry has seen an explosion of foreign investment since President Albert? Fujimori's government was first elected in 1990. Since then, Peru has taken some large steps toward recovery, making it the envy of most other developing countries. A measure of political stability was gained in 1992 when Shining Path leader Abimael Guzman was captured. In addition, the country has taken on a huge privatization program, rewritten its foreign investment laws and has reined in its annual inflation rate from 1,700% in 1990 to about 8% by late 1997. Small wonder then that attendance at the XXIII Peruvian Institute of Mining Engineers conference reached a record level, many of whom are employed by some of the world's largest mining companies. About 2,700 mining industry professionals from all over the world attended the week-long event, held in late September in Arequipa. That was an increase from 1995s 1,600 attendees, that meeting also held in Arequipa.

Jan 1, 1998

By W. S. Fyfe

Gold is mobilized or made soluble under all crustal conditions given appropriate fluid chemistry with molecules which complex gold. In the surface environment chloride, thiosulphate and a host of organics may mobilize gold. In the epithermal range bisulphide appears effective as shown by the classic studies in the Taupo volcanic zone of New Zealand. In the high grade metamorphic to igneous ranges little is know but it appears that gas molecules in the system CO2 -CO-H20-S-C1 can do the job. Precipitation may occur by changes in P-T-EL-pH or boiling where such changes influence the liquid concentration. Of the known regimes information is good for epithermal systems, poor for surface lateritic environments, inadequate for high-T systems. Gold is often concentrated in bio-systems both living and dead. The influence of biosystems is little appreciated. There is a great potential for the discovery of new types of gold deposits and in particular, gold in weathering environments, gold in very high-T environments, gold in strike-slip faults and thrust regimes, and gold as a by-product in materials like coal and other organic debris. By the year 2500 we may find our noble metal resources in the asteroids.

Jan 1, 1987

By A. Choudhury

Deep open-pit mines are becoming increasingly common in the highly mineralized arctic and sub-arctic regions. Air inversion is a frequent occurrence in these regions, and is exacerbated by complex geometry of the open pit and the surrounding natural topography of an open-pit mine. The resulting inversion cap is known to contribute to the degradation of air quality in the open pit, resulting in loss of production. This paper discusses the development and validation of a three-dimensional model that simulate the flow of air and the transport of gaseous contaminants in an arctic open-pit mine and the analyzes effect of the geometry of the mine and the slope angle of the pit on the contaminants profiles in the mine.

Feb 27, 2013

By R. J. Sweigard, R. V. Ramani

Three case studies were undertaken to investigate the role of land use potential evaluation in reclamation planning and to determine the impact of regional differences on final land use plans. The three surface mines studied were representative of operations in the Appalachian, Interior, and Northern Great Plains provinces. The scope of the investigations included a survey of regional characteristics, a detailed investigation of the mining operations and site conditions, and an assessment of local land use planning activities in the area of the mines. Special attention was given to key factors that presently determine the use of reclaimed land. Also, for each case study, the postmining land use potential was evaluated using site planning principles. Specifically, the environmental, economic, and social impacts of several potential postmining land use plans were considered.

Jan 1, 1987

By Steven F. Hoerger

Newmont Gold Company is the largest producer of gold in North America. Accurate resource estimates are critical to planning the mining in a year of over 90,000,000 t (100,000,000 tons) of mill, leach and waste grade material, from which over 47 t (1,500,000 oz) of gold are recovered. Resource estimates are updated frequently to take advantage of new drilling, improved geologic understanding and additional production reconciliations. At Newmont Gold, indicator kriging is the primary method being used to create resource estimates. Indicator kriging (IK) is a well accepted method of resource estimation; however, many details of the IK process which are critical to producing a useful resource estimate have not been well documented. An IK model must have several characteristics in order to be a useful resource estimate: the model must take into account geologic features of the mineralization; model creation cannot require too .much time; the model must accurately reflect the effects of selective mining; the model must be stored in an easily accessible format; and the model must be useable with a variety of cutoff grades. This paper will show how Newmont Gold implements the IK process in order to achieve these goals.

Jan 1, 1992