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By John D. Welsh

Heap leach pad liners are important to leach operations for maximizing recovery of gold bearing solutions and minimizing potential environmental impacts. Liners must be designed so that they can be built economically, but careful attention must be paid to the potential for liner damage during installation or placement of ore on the completed pads. This paper summarizes field experience gained on several leach pad construction projects in Nevada. Both soil and synthetic membrane installations are discussed. Emphasis is placed on principles that should be considered during design to provide economical and practical leach pads.

Jan 1, 1987

The last twenty years of development in Process Mineralogy are reviewed. Since the milestone review by Henley in 1983, which projected the concept and suggested closer working relations between mineral processing and mineral science, the second generation (1983-2003) has made significant progress. Examples are to be found in improved sampling and high-confidence flotation testing, and in automated quantitative mineral measurement. The recent addition of end-member studies has provided a clearer view of the overall ore mixture milled from its constituent geological components. In all, better predictive abilities have resulted from these improvements to Process Mineralogy. These improvements have led to more significant business impacts in mineral resource characterization, and in optimization of existing concentrator operations.

Jan 1, 2004

By MSHA

Not quite a year ago, during a speech to a group of mining professionals in Washington, DC, the subject centered around the long-range importance of conducting research projects and how much that research needs to specifically apply to health and safety matters in our industry. The point was made about the critical need to work together with government, private industry, labor organizations and academia speaking with a unified voice as we all march into the future together. The fundamental benefits of competitive research were mentioned -- to improve our quality of life, to develop our energy resources, to achieve a safe and healthy environment and to ensure long-term economic growth. Very importantly, emphasis was given to the natural link that makes my agency, the Mine Safety and Health Administration, and the National Institute for Occupational Safety and Health -- NIOSH -- the beneficiaries of each other's findings.

Jan 1, 1999

By S. D. Bearden

The world's barite reserve base is adequate for at least 100 years at the current consumption rate. China, India and the United States are expected to remain the leading producing countries, and the United States will continue to be the largest consumer. None of the known substitutes for barium sulfate are expected to impact existing applications. World production in 1995 was 4.41 Mt (4.86 million st), which is about 50% of capacity. Consumption is directly proportional to hydrocarbon well installation activity. Imports are expected to continue to supply more than half of the US requirements.

Jan 1, 1997

By G. M. Riddle

As an important part of the concept validation phase of the MX Advanced ICBM development program, Air Force System Command's Intercontinental Ballistic Missiles (ICBM) Program Office developed and demonstrated large trenching and cast-in-place equipment for placing many miles of buried concrete tunnel rapidly and economically. A tunnel or "buried trench" containing a mobile ICBM is one of the candidate basing models for MX. Upon remote command, the cannister housing the missile would break out of its concrete tunnel and earth overburden by erecting itself to a suitable angle and then launching the missile. The ICBM Program Office developed two each trenchers, cast-in-place machines, and breakout mechanisms, as well as a mobile concrete truck unloader. The machines were demonstrated in varying soil conditions in the southwest US. The breakout mechanisms were demonstrated nearby as well. This chapter describes the development program, the machines, and the demonstrations. No manuscript received

Jan 1, 1979

By J. Searls

The potash review arrived too late to appear in the June issue. Potash is a general term that includes several water soluble potassium salts: potassium chloride (muriate of potash), potassium sulfate (sulfate of potash), potassium magnesium sulfate (sulfate of potash-magnesia), potassium nitrate (niter) and sometimes potassium carbonate. Potassium carbonate was the original potash when it was leached from wood ashes and dried in large, cast iron pots to black-to-gray crystals (ash) to form "pot ash." "Pearlash" was potash roasted to white crystals. In modern terminology, the great preponderance of "potash" is the mined forms. It is estimated that 95% of the potash mined around the world is used as fertilizer. In 1840, Justus von Liebig demonstrated to the scientific community the importance of potassium to the growth of plants. But there was no low-priced source of potash available at that time. In the winter of 1851-1852, minable potash was discovered near Stassfurt,

Jan 1, 1991

By Peter D. Warwick

Recent investigations conducted by Federal, State, and industry organizations suggest that significant coalbed gas resources may exist in the Cretaceous and Paleocene-Eocene coal beds of the Gulf of Mexico Coastal Plain. Exploration efforts have focused on three areas which are in south Texas, north-central Louisiana, and south-central Mississippi (Figure 1). Coal-bed gas production is currently underway in south Texas and in north-central Louisiana. In Mississippi, several test wells have been drilled but no data are available on their production potential.

Jan 1, 2005

By Betty L. Gibbs

Mine planning and scheduling done with computer programs is possible only after extensive work has been completed to define the geologic extent of an ore body and an overall mine design. Mine planning methodology on computer can vary from computerized engineering tasks through systems which completely optimize a plan with little input from an engineer during the actual scheduling process. However, a strong emphasis is placed on producing practical mining sequences which may be "best" rather than "optimum". This section offers several viewpoints on the planning process using computers. Interactive planning and scheduling systems are attractive for many companies because they are easy for engineers to understand, and the results are acceptable. The engineer develops an open pit mine sequence by trial and error using interactive graphics. The results of this approach can usually be improved. A computer program can help an engineer make many trials in a short time period and provide a higher level of confidence that a "best" plan has been generated.

Jan 1, 1989

By Christopher J. Bise

During the past two decades, the emphasis on technological advances in US underground coal mining has focused on longwall mining. But there also has been a steady, although less spectacular, advance in the state-of-the-art in room-and-pillar mining. This has been stimulated by the successes of longwall mining in mine cost reduction, increased availability and improvements in haulage infrastructure, such as conveyor belt haulage. In addition, changes in management practices, such as nine- or 10-hour shifts, and marketing pressures have resulted in changes in the use of equipment. The net result of these changes has been the creation of modern room-and-pillar operations where average production levels currently exceed those considered very good 20 years ago. In fact, current production levels considered outstanding were considered unattainable two decades ago.

Jan 1, 1995

By Don Rose

Steel-fiber-reinforced-shotcrete (SFRS) methods of testing and the wording of specifications vary from country to country. In the USA ASTM C1018 is widely used. The Canadians have taken a close look at C1018 and point out that exact determination of the first crack is very subjective, and they propose a method of design that eliminates this variable. The Europeans (EFNARC) have taken the principles of testing a step further than ASTM C1018, and have added a new step in measuring the effectiveness of SFRS. EFNARC uses an "energy absorption" of a plate loaded in its center, in addition to the principles of C1018. The principles of SFRS design are also used in Japan, Norway and elsewhere.

Jan 1, 1999

Reclamation of surface mines is a crucial environmental issue and a key challenge to the worldwide mining industry. One of the goals of reclamation is to ensure that the area is left in a condition permitting safe future use. Hence, the reconstruction of open pits, waste piles and tailings dams must satisfy appropriate geotechnical stability and safety conditions for the planned use. Landscaping in the final stages is highly relevant as the topography around the mining areas is sometimes dramatically modified by ore extraction. The reclamation strategies must be applied not only after ore exhaustion, but also during its extraction. This is a sound business strategy that leads to considerable environmental benefits and increased security of the mining operations.

Jan 1, 2003

By Mike Jahraus

The topic I would like to throw out for discussion this morning concerns the metallurgical solution management of operating a valley fill leach facility where ore depths approach 250 feet and deeper. We are currently beginning to experience solution transport times through our heaps on the order of 60 to 70 days as our heaps approach 250 feet. Incorporating a two-stage leach scenario, or solution enrichment, these times are nearly doubled. Concurrent with the increased solution transport times, the solution tenors being produced by our heaps are being diluted slightly as percolation occurs through the lower lifts. I feel the best way to handle these situations is to closely monitor solution application rates, and carefully manage ore stacking. Also, as heaps become deeper, metallurgical and hydrologic characteristics of the ore become inter-related, i.e. if channeling or preferential flow is taking place, lowering cross-sectional flow rates to older leach panels with help re­institute capillary flow while helping to prevent solution tenor dilution.

Jan 1, 1999

By Z. Kowalski

Landfilling of waste causes the degradation of natural environment, not only due to land occupation, but also due to pollution of air, water and soil. The flotation waste from zinc-lead industry also poses such problem. There is a need to find the way to utilise substantial amount of these wastes and backfilling seems to be a good solution. Recently, in Poland only sand was used for backfilling. However, it will be more beneficial to substitute the sand with the industrial solid waste, especially flotation waste. The tests were performed in the laboratory to examine the use of flotation waste as a main ingredient for backfilling. The use of flotation waste is possible only when it is combined with other waste with specific bonding properties, especially regarding the prevention of leakage. The outcome of tests shows that flotation waste combined with cement and fly ashes can be used as a backfilling material. This paper presents the preparation of flotation waste for using it for backfilling.

Jan 1, 2006

By R. Markovic

The objective of this research study was the investigation of heavy metal removal from wastewaters of the "SARAKA" stream by using low-cost materials. These wastewaters flow into Krivelj River and through the network of existing rivers into regional water reservoirs. Sawdust, cardboard and fly ash were used as reactive materials in laboratory studies. Sawdust was obtained from oak and fir-wood while fly ash from heating station Bor, bitter-oak and oak. Experiments were carried out using real Saraka stream wastewaters and the degree of removal for iron, copper, manganese and zinc was investigated. The content of these heavy metals in Saraka stream wastewaters was under the limit of III and IV class of water (Law on Water - Official Register of the Republic of Serbia). Parameters such as flow rate of water, pH and effluent volume, contact time between water and reactive material, etc, were monitored during the experiments. All used materials give satisfactory results for iron and other heavy metals removal; the highest degree of removal was obtained by using fly ash.

Jan 1, 2006

By Chas. E. Shumate

There is assembled here this morning in Chicago the heartland of America, what is undoubtedly the greatest concentration of Technical, Scientific and "CAN DO" knowledge ever assembled in America. The participation in this Conference by the representatives of so many nations is particularly impressive and is a further indication of the importance of the subject matter of this conference which you will be discussing in much detail during the next few days. Another impressive feature of this Conference is the participation of a large segment of the construction industry in whose hands fall the job of building what others design. Also strongly represented is the manufacturing industry whose capability is well known throughout the world. They have the resources to design, develop and manufacture the machines and specialized equipment needed to do any job which the world requires. You should not expect to gain any knowledge from my few remarks this morning as I am undoubtedly the least qualified individual in this room on the highly technical and scientific subjects you will be discussing during these next few days. However, I shall offer a few broad suggestions on subject matter which I trust may generate serious thought during your discussions.

Jan 1, 1997

By J. Gawler

In June 2005 the Minerals Council of Australia signed a Memorandum of Understanding (MoU) with the Australian Government which states an intention ?for mining companies and government to work together with Indigenous people to build sustainable, prosperous communities in which individuals can create and take up social, employment and business opportunities in mining regions?. Implementation of the MoU has begun with demonstration sites established across Australia. All sites are using a Regional Partnership Agreement (RPA) model as a framework for enabling local people to find local solutions to local issues in partnership with mining companies, governments and Indigenous communities. Mining and resources companies can provide important input into regional economic development and capacity building by working through local partnerships. Company benefits include gaining a social licence to operate, access to a reliable skilled workforce, better longterm relationships with Indigenous communities and sustainable regional communities. All levels of government, Australian, State and Local, are working collaboratively to address unemployment and other issues in remote Indigenous communities. The Australian Government has adopted RPAs as one mechanism for implementing its whole-of-government approach to Indigenous affairs. This leading edge work is unique to Australia and the model has applications and significant learning for other countries and industries.

Jan 1, 2007

By R. F. Kovar, R. N. Torbin, R. E. Gundersen

I have to express my .surprise and must send a note of warning concerning the use of polyurethane foam as described in a paper by R.N. Torbin and R.F. Kovar, entitled "Innovative Shaft Lining Method," published in your February 1989 edition. In September, 1986, 177 miners lost their lives when they were exposed to fumes downwind from a fire in a tunnel lined with polyurethane foam. Whilst polyurethane exhibits reasonable fire retardent properties in small-scale tests, mass use in a tubular configuration, exacerbated by the furnace effect of cross-radiation, can lead to a rapid, uncontrollable conflagration. I do not wish these comments to detract from the engineering achievements of the authors but rather to sound a loud warning as to the application of the system. Any shaft designed for human access- be it for transport or shaft work - and any intake airway, should not consider the use of polyurethane foam. It only needs a slip with a cutting torch or an electric fault to initiate a disaster. Many countries have banned or restricted the use of polyurethane foam in the workings of a mine and maybe alternative foams (e.g. phenolics) can be used or developed

Jan 1, 1991

By P. Ollivier

A comparative study on potential refractory ore processing techniques was launched at the BRGM to enable exploitation of numerous small deposits of arsenopyrite and antimony sulphide ores.

Jan 1, 1998

By Antonio Peralta

Mining activity in Mexico began in the 16th century when the Spanish realized the mining potential of the new territory. Since that time, mining has evolved into a strong and vital industry for the country. Good professionals in the mining-related fields are fundamental to the growth and improvement of this industry. Since the end of the 18th century, formal education in mining has been available at the University of Guanajuato, in Guanajuato, Mexico. This school created one of the first schools of mines on the North American continent in 1828. In recent times, some other programs have been created at other universities. Universities offering mining related programs Listed here are the seven universities in Mexico that offer mining related degrees. They are the University of Guanajuato, UNAM, the University of Zacatecas, the University of Chihuahua, the University of Sonora, the University of Coahuila and the University of San Luis Potosi. The University of Guanajuato is the only Mexican university that offers graduate studies at the master's level. No PhD programs in mining engineering are offered at any Mexican university. Programs at each university are of different duration. They are: • University of Guanajuato-Five-and-a-half years, divided into five years of classroom instruction and six months in the working place. • University of Zacatecas - Five years of classroom instruction.

Jan 1, 1994

By Alan L. Mierke

West Virginia's economy has been closely linked with coal. West Virginia is consistently one of the top three coal-producing states. Its 149 Mt (164 mil¬lion st) produced in 1992 represented 16.5% of total US coal production. In recent years, the state's economy has experienced a diversification away from its traditional employment base of min¬ing and heavy manufacturing. However, the coal industry remains an integral part of the lives of West Virginians. Coal is mined in 33 of the state's 55 counties. In many of these counties, the coal industry is the largest private employer and contributor to the economy. West Virginia has three major coal-producing regions. The northern region produces coal high in gas and sulfur content (steam coal). It is consumed primarily by utility and industrial markets. The southeast region produces high-grade coal low in sulfur content but high in carbons and Btu (metallurgical coal). The southwest region produces metallurgical and steam coal. The high-grade metallurgical coal is used in the production of coke for steel manufacturing. Metallurgical coal also comprises the majority of coal exported from the United States. During 1993, West Virginia was the country's largest exporter of coal, accounting for 44.5% of total US coal exports.

Jan 1, 1995