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By H. G. Fleshman

Thousands of years ago, Chinese water well drillers developed a technique for punching holes in the ground by lifting massive metal bits and letting them fall against the rock. With diligence, they could pound away about 2 feet a day. The Chinese drillers pounded holes in the ground this way for almost 2000 years. In the 1860's, French water well drillers developed a perforated bit moistened by fluids pumped into the hole through a hollow rod. The fluids carried the cuttings from the hole and spared the Frenchmen the task of bailing them out by hand.

Jan 1, 1986

Iron ores may be upgraded by flotation of iron oxides or siliceous gangue using either cationic or anionic collectors. The electrostatic mechanism of adsorption can account for the complex chemistry involved. In industrial practice, only cationic silica flotation is used at present in North America. Some of the seemingly paradoxical phenomena of cationic silica flotation behaviors in meeting the demand for low silica concentrates are reviewed.

Jan 1, 1989

By F. Calizaya

A booster fan is an underground fan installed in series with a main surface fan and used to boost the air pressure of the ventilation air passing through it. To accomplish this objective, the fan is installed in a permanent stopping and equipped with airlock doors, a monitoring system, and interlocking devices between main and booster fan controls. The stopping and doors are used to prevent flow recirculation, and the monitors to ensure safe operation of the fan. A booster fan, properly sized and sited, can be used to create safe work conditions and allow the extraction of minerals from areas that would otherwise be uneconomic to mine. In deep and large mines with heavy emissions of air contaminants, the required quantities of air can only be supplied by using high pressure fans. These fans will inevitably induce significant losses of fresh airflow through the stoppings and doors. For well defined ventilation circuits, booster fans can be used to decrease the main fan pressures and reduce the leakage flows. However, this will require a good understanding of the correct ventilation practice, from planning to operation and maintenance of booster fans. The objective of this study is to investigate the conditions under which booster fans can be used safely and efficiently in underground coal mines. Specifically, the study is directed at (1) collecting reliable information on airway resistances and flow requirements from two large U.S coal mines, (2) collecting fan performance data from one or more existing coal mine where booster fans are used regularly, (3) monitoring the performance of booster fans in a laboratory model and an experimental mine, (4) developing a booster fan selection method to assist the ventilation engineer at the planning stage, and (5) training six M.S. or Ph.D. graduate students in advanced mine ventilation.

Jan 1, 2010

By M. M. Veiga, M. Koehoorn

This paper reports on recently completed research that investigated the health fabric of mining communities in British Columbia (BC), Canada. The project, funded by two national funding agencies and the BC Government, and supported by numerous provincial organizations, marked a collaboration between mining engineering and health researchers. The study employed mixed-methods. First, a quantitative phase merged census, mining industry and health data to investigate the relationship between declining economic conditions and health outcomes (mental illness and stress-mediated cardiovascular disease). Second, a qualitative phase investigated community health issues associated with the mining boom-bust cycle from the perspective of health and social service providers working in a northern BC coal mining community. Third health research findings were disseminated to potential knowledge users in the hope of enhancing mine impact assessing and integrated mine planning. The paper provides a synthesis of the research methods used in this project, and highlights the main indicators used and key findings. It concludes by identifying recommendations, and future research needs considered to be of particular importance to the health and sustainability of mining communities in BC, Canada and around the globe.

Jan 1, 2011

By Robin J. Batterham, Stephen H. Algie

It is often stated that innovation is central to the economic survival of mining and mineral processing in the face of global competition, and yet technology is often far from a core strategy in our industry - hence the concerns that are often voiced about the apparent slow rate at which new technology is applied. Much of the discussion stems from a lack of understanding of the role of technology in innovation, and of the role of R&D within the innovation process. To a large extent this has all been said, however, the messages are clear and deserve repetition. This paper expresses the personal views of the authors, based on experience in government-funded (CSIRO and universities) research, and in CRA Ltd, a large mining and mineral processing company. Further than this, it explains how our own development unit within the CRA Group has come to see its key roles as including the transfer of technology, and the training of technologists to move into the operating business units. We conclude that these critical tasks are the keys to creating the environment that will allow us to maximise the contribution of technology.

Jan 1, 1995

By S. Chander

The mechanism of oxidation of sulfur in pyrite is a function of the rate and driving force for oxidation. New evidence is presented in this article to show that at moderate potentials, a sulfur-rich hydrophobic layer is formed. Under ordinary conditions, the sulfur layer is covered with a layer of iron oxides, hydroxides, sulfate or oxy-sulfide ions. Under these conditions, pyrite is hydrophilic. In the presence of iron-chelating agents or iron sequestering ions, iron layer might not form. Under these conditions, sulfur-layer is exposed and pyritic might become hydrophobic. Stronger oxidizing conditions decompose the sulfur-layer, thereby making the surface hydrophilic.

Jan 1, 1992

By P. Anciaux

The EUs? manufacturing and construction industries are vital to Europe?s economy. They rely heavily on a steady supply of materials which meet appropriate quality criteria and are available at a competitive price. The steadily rising global demand for (non-energy) raw materials due to increasing consumption in upcoming economies such as China, India and Brazil, is in some cases leading to rapid price increases, but also supply disruptions which affect the European industry chain. These considerations are at the basis of new policy initiatives that are being prepared by Enterprise and Industry Directorate-General in relation to the competitiveness of the European metals industry. Over the last year the raw materials supply issue has increasingly become the topic of de-bate among various stakeholders. In July 2006 the European Economic and Social Committee adopted an opinion on risks and problems associated with the supply of raw materials to European industry. It is therefore important to identify and analyse the future needs for European industry, the possible constraints and impacts on its competitiveness. The raw materials supply issue should also be looked at from the view-point of the EU extractive industry, which plays an important role in supplying raw materials to the downstream industries and which faces very specific challenges. Within the Enterprise and Industry Directorate-General the different factors that influence the competitiveness of the non-energy extractive industry are being assessed, in order to help identify policies and actions which could contribute to and enhance the competitiveness of the industry.

Jan 1, 2007

By Brian Hester

Many Third World African countries are well-endowed with minerals - especially gold and diamonds - while only a few have important base metal deposits. For decades since colonial rule, political and economic conditions discouraged interest by Western capital. Influence from Soviet Bloc countries, however, has declined with the move toward multi-party rule. And the left wing orientation, once widely favored by Third World African countries, has almost disappeared. With International Monetary Fund (IMF) encouragement, these Third World African countries now encourage representational government and solicit western finance to expand their industries. Mining is especially encouraged. The North American mining industry is following the same trail as other capital intensive industries and looking abroad for opportunities. The Prospectors and Developers Association of Canada released figures that show exploration expenditures in that country were halved between 1987 and 1990. Figures for the United States are not so easily found but every indication points to a downward trend. While total annual expenditures on US exploration by corporations as a group are either declining or remaining constant, expenditures away from North America is increasing. Gold exploration expenditures in 1991 by the major companies tracked by Minerals Economics Group were less in the United States than for Latin America and the Southwest Pacific combined. The same study showed as much was spent in the Republic of South Africa and "Other" areas combined as in the United States. Expenditures by major corporations in these "Other" areas amount to only 5.2% of their total budget. Third World Africa is a major component of these "Other" areas.

Jan 1, 1993

By Mark J. Zdunczyk

Short Mountain Silica mines the Clinch Formation, an orthoquartzite, for silica sand. The operation is located near Mooresburg, TN, about 80 km (50 miles) northeast of Knoxville. Short Mountain is a local geographic name given to an area of resistant sandstone (Fig. 1). The area is part of the Clinch Mountain system that extends from eastern Tennessee to southwestern Virginia. The thick sandstone unit is more technically called a quartz arenite (orthoquartzite) that forms most of the mountain. In 1980, a Knoxville resident brought the Clinch Formation - Short Mountain in particular - to the attention of the large silica-sand producers as a potential silica-sand mine. Working with a local contractor who owned several hundred acres on Short Mountain, the Knoxville resident contacted interested companies. Many silica companies reviewed the property including Ottawa Silica Co., Pennsylvania Glass Sand Co. (both now US Silica Co.),Unimin Corp.,The Morie Co. and others. AFG Industries was the main market for the glass sand product from this potential mine. It had two plants, both within trucking distance from the site. All the silica sand producing companies, however, declined to develop the site. A few years later, Unimin Corp. decided to drill and evaluate the deposit. From that evaluation, Unimin leased the property but later dropped it. The relatively limited market for the Short Mountain product as well as Unimin’s recent acquisition of Carolina Silica were reportedly instrumental in the company’s decision to let go of the lease. Several other companies-unrelated to the silica sand industry - looked at the site but no one was interested in developing it. In 1986, J.D. Nicewonder, owner of coal mines in Virginia and Kentucky, was approached to investigate the site. Nicewonder began to develop the site with the intent to produce glass sand to supply AFG Industries. In May 1988, the first shipment of sand was trucked to AFG Industries.

Jan 1, 1992

By John Marshall

Silverton was the queen city of the western mining towns in the early 1900s. Located high in the San Juan Mountains, the town constantly grew and changed. Yet, it was subject to the vagaries and whims of economics, politics and disasters, natural or otherwise. Breweries, smelters and sawmills serviced Silverton's swelling mining population, which reached several thousand at its peak. Two trains a day ran from Durango to Silverton, in addition to trains running from Silverton over the top of Red Mountain on to Ironton. They ran up Cement Creek to the little town of Gladstone and up the Animas River Valley to Howardsville, Eureka and Animas Forks. During these prosperous times, construction flourished. There were plenty of wooden structures, and many of these stand today. The first brick buildings were built by bricklayer Patrick Stanley in 1877. It took quite a while for the first car to arrive. Almost 28 years passed from the coming of the first train to the arrival of the first car. It was brought over 3,840-m (12,600-ft) Stony Pass from Creede, CO, in an incredible journey retold years later by Louis Wyman. "Dad's daydreams were not the idle musings or the fantasies of a mystic," Wyman said. "They had a way of erupting into reality. He advocated and built good roads," he said. "During the summer of 1910, he was up to his sweatband in a project that took in half the state of Colorado. He envisioned an automobile highway, unheard of at that time, running southwest from Denver through the scenic grandeur of the high Colorado Rockies. The road would traverse a thousand miles or more of the state's finest recreational land finally circling back to Denver. Years later, when all of the county roads had been connected, it became known as 'Colorado's Thousand-Mile Circle Route.' Of course, Silverton and the San Juans were bright stars along the way."

Jan 1, 1997

By A. E. Isaacson

The Bureau of Mines is studying the effect of supercritical water, at 4000 C and 3,500 psi and subcritical water at lower temperatures and pressures. on mixtures of minerals and metals to determine the possible applications of water at high temperature and pressure for processing these materials. This research was conducted using a flow-through bench-scale system. Copper-bearing minerals studied were chalcocite, chalcopyrite, covellite, and cuprite. In general, mixtures of copper minerals and pyrite reacted to form bornite. Intermediate phases formed were chalcopyrite and digenite. Similar reactions occurred between pyrite and metallic copper. A mixture of chalcopyrite and pyrite was inert in supercritical water. The reaction between cuprite and metallic zinc yielded metallic copper. The cuprite was reduced by hydrogen generated by the reaction between metallic zinc and water. None of the reactions occurred exclusively in supercritical water, but also occurred in water at high temperature and pressure below the critical point. Experimental results did show that a dual-reaction process, consisting of solid-state diffusion and fluid transport, was occurring.

Jan 1, 1989

By A. Gene Collins

The demand for lithium may increase because of its potential use id lithium batteries and in the generation of electrical power by fusion. Therefore, lithium abundance in some United States oil-field brines was surveyed. Oil-field brines from numerous locations were found to contain more than 100 mg/l lithium and several exceeded 500 mg/l. An area of 25,000 km2, with a reservoir thickness of 60 m, an effective porosity of 5 percent, and a brine with a specific gravity of 1.2 containing 100 mg/l of lithium, contains about 0.75 x 106 tonnes (1 tonne = 1 metric ton = 1,000 kg) of lithium in 7.5 km3 of brine. It is postulated that the brines were enriched in lithium by lithium-rich spring water or lithium leached from volcanic rocks followed by evaporation sequences.

Jan 1, 1978

By R. Poulin, R. C. Pakalnis

Approximately 51 % of all ore production in Canadian underground metal mines is derived directly from open-stope operations. This method requires that large excavations remain open until the ore is extracted with a minimum acceptable level of dilution. A survey of underground mines in 1988 reported that a major factor in their closure was uncontrolled dilution. It has been reported that 40% of openstope operations were experiencing dilution in excess of 20%. This level of dilution has significant implications on the economic viability of a project, especially when one considers that a rate of return on a positive project is generally between 10% and 20%. This paper reports on the various definitions of dilution, on the methods of stope design that are presently used with the objective of reducing dilution and on a recently available survey technique that enables dilution to be quantified.

Jan 1, 1996

By C. Mermiris

Bauxite ores in Fokida belong to Parnassus-Giona zone and are found exclusively in limestone in two bauxite horizons, which are of great economic importance and with very unfavorable conditions for the reclamation process. The ore bodies are usually less than two million tones. They are in many cases encountered near the surface as a result of the erosion and are exploited either with open pit or underground methods. Mining activity, which dates back 70 years, causes many changes to the environment and most of all to vegetation and landscape. The first step to mining exploitation of bauxite ores is the selection of an underground or open pit method taking into consideration mostly economical and technical criteria. Open pit exploitation, which causes the most severe environmental consequences, is done with the method of vertical benches in hard rock with the use of explosives. The impacts on the landscape that result from the method of vertical benches are: ? The front of the excavation that is usually solid rock of the hanging wall (limestone). The height of the benches varies from 10 to 20 meters and the gradient of the final slope is designed to be around 65o, unless the rock is not so stable and the gradient is reduced accordingly.

Jan 1, 2002

By Allan J. Breitenbach

The heap leaching process has developed into a low-cost method for recovering copper, gold and silver from large and small deposits of low-grade ore. The earliest known heap leaching process with chemicals occurred in about 1752 and is attributed to Spanish miners percolating acid solutions through large heaps of oxide copper ore on the banks of the Rio Tinto (Ran Zyl, et al., 1988). In 1969, US Bureau of Mines research¬ers proposed the use of dilute alkaline cyanide solutions as a low-cost means for recovering gold values from low-grade ore containing micrometer-sized particles of gold (Miners News, 1991). The modern-day heap leaching process typically involves the percolation of leach solutions through controlled lifts of stacked, low-grade ore (crushed, aggomerated or run-of-mine) in a heap for chemical extraction of precious and base metals into solution (Fig. 1). The enriched (pregnant) solution is collected by gravity flow in lined basins, sumps and ponds for processing and recovery of the target metals (copper, gold and silver). The barren solution from the recovery facilities is recirculated to the heap, along with chemical reagents and makeup water, for containment of all process solutions in an enclosed and environmentally sound system. This involves the use of low-permeability liner systems beneath the heap leach stacks to maximize solution recovery and protect the underlying ground water (Fig. 1). This article discusses the typical heap leach liner systems currently used by mining companies in North America. The most successful heap leach pad liner systems from past precious metal operations generally include an underlying, low-permeability soil bedding material; a geomembrane liner, and an overlying protective cover fill.

Jan 1, 1994

By P. Venkatsubramanian, D. R. Maneval

An insufficient hydrologic data base exists for most large and small coal basins in Alaska owing to the lack of need in the past to collect data. The runoff process is insufficiently understood which is complicated by specifically northern phenomenon, and the lack of understanding of hydrologic relationships in permafrost environment. This paper presents an understanding of the hydrologic effects of frozen ground and presents methods by which the influence of surface mining upon the hydrologic balance can be analyzed.

Jan 1, 1987

By S. Rideout

As Assistant Director for Program Support for the Office of Surface Mining Reclamation and Enforcement (OSM), a bureau of the U.S. Department of the Interior, I am responsible for the regulatory and abandoned mine land programs under the Surface Mining Control and Reclamation Act of 1977, which governs the environmental impacts of coal mining. My perspective is influenced by my current position and my previous positions in government and private industry. Sustainability is a cooperative effort of many parties and can only be achieved if each assumes their responsibilities for making it happen. I will highlight some of my thoughts on the role of government in achieving sustainability in the mining arena.

Jan 1, 2007

Currently the challenge that our society faces is to combine the economic activity for the continuously increasing needs of our expanding population with the necessary environmental integrity and the humanistic social concerns. In this paper, the methodologies that should be applied by the progressive mining industry in order to fall within the frame of the sustainable development are summarized. The Sappes project, an advanced gold mining project in north-eastern Greece, is presented together with the approaches adopted by Thrace Minerals S.A.

Jan 1, 2003

By Keith G. Wallace, Daniel J. Brunner

The traditional approach to mine ventilation planning involved making estimates of airflows, including leakage routes, and summing the corresponding pressure drops along consecutive paths in order to determine the fan pressures required. This methodology changed completely with the availability of computers. Mainframe digital computers began to be used for mine ventilation network analysis in the mid-1960's. Their use spread rapidly throughout the world in the 1970's. Mainframe machines were employed owing to the need for high speed numerical procedures and substantial storage requirements. However, during the past decade, the growing availability of low cost but powerful microcomputers has allowed the development of net- work analysis programs that can handle ventilation systems of hundreds of branches, and which can produce results within a few minutes. This paper discusses recent advances in software and hardware development specific to mine ventilation planning. Software developments include interactive data and output manipulation, graphical representation of output, internal checks on input parameters to preset ranges and subroutines which calculate the gas distribution throughout the network from known gas sources. Hardware advances have led to significant increases in memory to facilitate the analysis of large ventilation models, math co-processor chips which greatly shorten run times, and plotter hardware for graphical output displays. Recent software developments make it possible to graphically display output on printers faster than on standard plotters.

Jan 1, 1989

By S. Behl

In the selective flocculation process, polymers with specific functional groups can yield highly selective adsorption and, therefore, high separation efficiency. Selectivity in polymer adsorption may also be attained by specific additives that inhibit the adsorption of the flocculant on some solid surfaces but not on others. Generally, these additives have a different chemical nature than the flocculant. In this study, the lower molecular weight fraction of the flocculant was successfully evaluated as a site blocking agent, leading to higher separation efficiency than obtained otherwise.

Jan 1, 1993