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By Romeo Jurani, Ralph Dresel, Fred Kissell, Charles Parker

This report describes actions taken to control silica dust at the Yucca Mountain Exploratory Studies Facility (ESF), a tunnel located in Southern Nevada that is part of a scientific program to determine site suitability for a potential nuclear waste repository. The rock is a volcanic tuff containing significant percentages of both quartz and cristobalite. Water use for dust control was limited because of scientific test requirements. A major dust reduction was achieved with an intermediate air cleaning station located on a rear deck of the TBM trailing gear.

Jan 1, 1999

By Gerald H. Luttrell, Roe-Hoan Yoon

Flotation columns are becoming increasingly popular due to their ability to improve selectivity and to reduce operating costs. Unfortunately, these advantages are not often realized because of poor operating practices and difficulties associated with design and maintenance. This article provides guidelines for the operation and design of columns. The discussion will focus on designing proper wash water systems for improved selectivity, maximizing throughput by increasing the bubble surface area rate, and minimizing operating and maintenance costs. It is suggested that the design of the air sparging system is the most critical element in column flotation.

Jan 1, 1993

By Håkan Tyni, Jan Björkman, Per-Olaf Samskog, Irving Wigdén

Process automation can provide better utilization of capital investments. Furthermore, it is a necessity for securing the high demands of product quality. In this paper, process automation in underground mining as well as in the beneficiation plant will be discussed. The development of reliable broadband communication systems for real-time transfer of image, audio and data have enabled remotely controlled LHDs and drilling rigs. In the beneficiation plants, model-based expert control systems far on-line dynamic process optimization and control have been installed in unit operations such as grinding, flotation and induration.

Jan 1, 2000

By T. Stuczynski

In the past ten years about 3000 wastewater treatment plants have been built in Poland. The result of this development has been a massive increase in overall sludge production. According to data supplied by the Ministry of Environmental Protection, 400,000 dry tons of sludge are generated every year in Poland (Koblak-Kalinska 1996). Still it is difficult to estimate the amount of sludge, which is used in agriculture or for reclamation purposes. However, it can be assumed that this comes to no more than 10 percent of all sludge produced in Poland on a yearly basis. Thus it became obvious that an urgent solution to this problem was needed. Local authorities in Silesia realized in the early 90?s that a demonstration was necessary to encourage the proper utilization of sludge. This was the basis for establishing the Biosolids Subpart of the Silesia Project, which addressed the use of biosolids in the reclamation of mining and smelting dumps (Stuczynski et al. 1996). Metal waste sites themselves are known to contain more than 87 million tons of waste (Pistelok et al. 1995). Each year this amount increases by approximately 400,000 tons. We realized that a simple solution for stabilizing these sites would be to cover them with vegetation in order to reduce leaching of toxic elements, as well as to keep metallic fugitive dust from entering the environment. The reclamation of smelter waste sites, which was carried out within the framework of the Silesia Project was a joint effort of local government, industry and international research institutions/agencies, including the US Environmental Protection Agency (EPA), the Center for Research and Control of the Environment (OBIKS), Virginia Polytechnic Institute and IUNG. One of the goals was to evaluate the possibility of adapting the rules of sludge management currently used in the United States to conditions commonly found here in industrial regions of Poland. However, the main objective of the Silesia Project was the development of guidelines concerning all aspects of sludge use for the reclamation of degraded lands and waste sites. Biological aspects related to reclamation of metal waste with the use of biosolids will be discussed in this paper.

Jan 1, 2002

By Andrew S. Lain

Before you begin mining aggregates in Oklahoma, you must first look at the market and ask these questions: (1) Is there a need for additional aggregate production? (2) Can we produce the aggregate efficiently enough to compete? (3) Is the deposit close enough to the market? If you can answer "yes" to each of these three questions, then you are ready to start the process for mining aggregates in Oklahoma. The first consideration to be made is whether the aggregates produced will need to meet state specifications. If you do not want to meet state durability standards, there are numerous formations you can mine and produce aggregates. We will deal only with the formations that will meet state durability standards. These formations are located in the southern half of Oklahoma and in the Tulsa area. Some of the formations that contain limestone, dolomite, and sandstone that will meet state durability tests are West Springs Creek, Kindblade, McKenzie Hill, Butterly-Royer, and Rush Springs Formations. Granite and rhyolite also are found in Oklahoma and can be used as construction aggregates. Once an area has been identified as having durable material, and drilling has verified its properties, a permit must be secured from the Oklahoma Department of Mines, Oklahoma Department of Environmental Quality, and any other applicable agency before construction of a plant occurs. There are many different brands of crushers available, but all work on one of two crushing principles-either compression breakage or impact breakage. Each type has its application in different industrial-mineral types and the desired end product. A typical small crushing plant would start with a jaw crusher for primary reduction, and then employ one standard cone and one shorthead cone for secondary reduction. One grizzly would be in the circuit with one finished-product screen and three to four finished-product stackers. Natural sands and gravels are found in rivers and old river channels. These too need to be tested to see if spec product can be produced. All of our sand operations have very little gravel; thus, we do not process the gravel. The sand is processed through classifying tanks for gradation.

Jan 1, 1999

By Albert W. Evans

Introduction Engineering Health and Safety is concerned with the understanding of the complex interplay between the risk of injury with technological ,environmental, individual, organisational and legal factors. With this understanding, the design and decision making processes can be balanced with the other objectives of industry and employment to arrive at solutions which place appropriate controls on technology and other aspects of human activities to prevent disease and injury to personnel in the coal mining industry and the design of safe production machinery and ancillary equipment. Advances in the detection and diagnosis of causes of diseases and the need for engineering health and safety in the coal mining industry has increased the need for appropriate education and training. Hazards arise in many forms; exposure to toxic chemicals, escape of radio - active materials, explosion of pressure vessels, contact with moving machinery, exposure to dust, environmental dangers such as excessive noise, high temperatures and manual handling etc. As technology advances, these dangers become more complex and less clearly defined and less easily perceived. Consequently, the ways of controlling the dangers also become more complex and wide ranging. The need to educate and train people in coal mining applications of engineering health and safety has been enhanced over the last five years and courses should be established to fulfil the need for competent people to deal with the problems which modern coal mining technology creates together with the legislation that governs engineering health and safety and to carry out research and development work in the coal mining industry. Industrial Involvement The engineering health and safety experts must be prepared to take a more active part in monitoring conditions that exist in the mining industry, and not design from information obtained from the mechanical, electrical and hydraulic expertise and off-the-shelf components from other industries. Surveying and control of the operating environment must be essentially the concern of the engineering health and safety experts and, whilst it is not possible to create a perfect environment for each machine, every effort must be made to minimise failures and hence plan for designs which will maximise

Jan 1, 1986

By Alan G. Fricker

Cyprus Gold NZ Ltd will be recovering residual free cyanide in barren gold pulp by air stripping. Laboratory investigations by DSIR have indicated additional advantages by recovering the cyanide from pregnant pulp. These are a lower leach pH, a greater cyanide recovery and less carbon consumption. They have a net economic advantage of $1.20/tonne over recovery from barren pulp. The realisation of these advantages is dependent on three crucial technical aspects -optimum pH for dissolution, the absolute loss of cyanide and the stability of the aurocyanide ion. The laboratory investigations described herein address these aspects. Earlier work had indicated that the rate of dissolution of freely revolving gold discs at constant cyanide ion concentration increased with decreasing pH from 11 to 8. Attempts to repeat the work in a more controlled manner by measuring the corrosion potential and current density have, to date, not been reproducible, but do not contradict the earlier observations. Cyanide recoveries and balances were obtained on leaches at pH 10.5 and 9 at the same cyanide ion concentration -the lower pH requiring three times as much total cyanide. Unaccounted-for losses, unfortunately, exceed the accounted-for losses, making interpretation of the balances difficult. Nevertheless, it appears that the additional amount of cyanide at the lower pH of 9 may not be fully recoverable. It may not, however, prove necessary in practice to use more cyanide at a lower pH. Both the gold and silver cyanide complexes remain available for carbon adsorption, as do mercury, copper and iron. Zinc, and probably cadmium, nickel and lead, may precipitate during stripping, which is an environmental advantage.

Jan 1, 1991

By David Williamson

In the post-World War II years, metals analysts and statisticians have tracked the demand for metals in line with changes in Organization of Economic Cooperation and Development (OECD) industrial production (IP) growth rates, Williamson said. This was because the correlation between IP growth and metal demand was reasonable. "However, the correlation was exaggerated," he said. During times of expanding IP growth, metal demand increased at a faster proportional rate than IP growth. This was probably due to industry restocking in anticipation of growing demand at the start of each economic cycle. Conversely, metal demand would slacken at a greater rate than would be suggested by negative IP growth as industry destocked to reduce costs. Nonetheless, he said, a reasonable correlation could be painted between IP growth over the longer term and metal demand. "Yet, although this correlation has stood well since the last world war, it has been based on the fact that the bulk of the world's IP growth stemmed from the industrialized countries of the western world, lately including Japan," Williamson said. The so-called "developing world" had been of little consequence. The Soviet Union and other communist bloc countries were deemed to be closed, self-contained entities that, for each metal, would either be net exporters or importers, he said. These quantities would be used by analysts to calculate the overall supply/demand equation for the western world only and to deduce whether a commodity was in shortage or surplus. It is now believed that this method of projecting total world supply and demand for raw materials is outdated, Williamson said. It does not take into account the worldwide political changes that have occurred since the collapse of communism and the revitalization of China. "It is no longer appropriate to assess global balances for raw materials on the basis of three economic blocs," he said, including the western world, developing world and communist bloc. Rather, global balances need to be projected on a global basis. In this regard, since the collapse of communism and the removal of many other totalitarian regimes, capitalist forces are attempting to satisfy the expectations of the great mass of the world's poorer people, Williamson said. Such people, usually located in Asia, Africa and Latin America, have aspired to the same standard of living as people living in western Europe, North America and Japan. "Now, with free market forces at work, their aspirations will start to be met." Consequently, the demand for metals and other raw materials will now rise at a much faster rate. The production of raw materials has to keep pace with rising IP in the developed world. It will also have to keep pace with the demands associated with the rising expectations of increasing populations in the developing world, as well as from within the old communist bloc countries.

Jan 1, 1997

By Paul C. Schmall

In recent years, several geotechnical methods have been successfully applied to ash pond closure. These include modified dewatering techniques with wellpoints and wells to physically drain the material, soil mixing to create a soil-concrete material for improved accessways as well as improved ground structures within ponds to act as barriers or gravity dams, and geotechnical instrumentation to serve as an early warning of the potential for liquefaction. Given the parallels between fly ash and sluiced in place mine tailings, the application of fly ash remediation method to mine tailings shows significant potential, as illustrated in this paper.

Feb 1, 2024

By D. M. Range

Exxon is reclaiming an 80 hectare (200 acre) Wyoming uranium tailings basin (10 Mt) in accordance with U.S. Nuclear Regulatory Commission requirements. The reclamation plan is designed to control the tailings and their radioactive emissions for at least 1000 years. Rigorous modeling and analyses of potential erosion by wind and water were used in planning. The use of riprap was minimized and the need for long term reclamation maintenance was eliminated. The resulting design is similar to erosionally stable regions created by nature. The concepts used in the design and implantation have wider reclamation application.

Jan 1, 1989

By Ian Larkins

The Ruby Hill Mine agglomerates crushed low-grade ore (nominally -1 .5'') with high-grade filtered tailings (filter cake, nominally 80% -65#). Cement is added as a binding agent. The agglomerated ore is then conveyed and stacked on the heap. In 1998 approximately $480 000 was spent on cement for agglomeration. Cement for mill pH control and agglomeration was the largest single reagent cost at Ruby Hill. In an effort to reduce agglomeration costs a test-work program was initiated to investigate alternative binders and optimum binder additions. This paper summarizes the test­work results to-date.

Jan 1, 1999

By Dudley Walls

In 1974 Amherst, Coal Company disposed of its 28 mesh X O thickener underflow (refuse) by pumping to ponds. Because of the very steep terrain surrounding the plant the pond capacities were limited which necessitated daily cleaning of the ponds on a three (B) shift basis. Needless to say this proved to be a very expensive as well as a very "untidy" operation. Faced with increased pressures from state and federal authorities as well as increased handling problems because of limited pond capacities, Amherst began looking for a different method for the disposal of 28 mesh X O refuse.

Jan 1, 1979

By I. P. Giannopoulou

Flotation tailings resulted from the mineral pro-cessing of mixed sulfides ores represent the main source of the generation of acid mine drainage (AMD). These solid wastes remain un-utilized in the disposal areas (tailing dams), while for their stabilization and the immobilization of the contained heavy metals highly costly management techniques are required. In the present paper the geopolymerization of the flotation tailings resulted from copper sulfide ores dressing process is investigated, as an alternative method for their treatment aiming at immobilize the contained heavy metals and utilize the produced materials as raw materials in the construction materials industry.

Jan 1, 2006

By G. Petrakis

The selection of suitable species of plants for the rehabilitation of mining disturbed lands is one of the most crucial decisions to be made concerning the success of planting revegetation. Native plant species are best suited for use in the work of reintroducing vegetation in rehabilitated areas. By using such species an increase in the success rate of rehabilitation is attained not only as regards yield due to their better growth ability (they are adapted to local climatic conditions), but also because of a better adjustment to and better visual harmonization with the surrounding unspoiled areas.

Jan 1, 2002

By Jim Morris

This paper will describe the excavation of a 5.4 percent decline at the Montanore Project for Noranda Minerals Corporation. The 5.3 m by 4.9 m tunnel was driven to provide access for the exploration of a major copper-silver deposit. Soft ground and conventional drill-blast mining were used on the 4,270 m tunnel. Ground support consisted of steel sets and concrete in the soft ground and pattern rockbolts providing the majority of the rock support. A special feature of the project was the use of conveyor haulage in conjunction with the drill-blast excavation.

Jan 1, 1993

By Haydn H. Murray

A hydrothermal bentonite located in the high Sierras in Nevada is being mined and processed to produce a natural dietary supplement. The minerals present are smectite, gypsum, jarosite, quartz, feldspar, kaolinite, goethite, hematite and zeolite. The clay material was analyzed for respirable crystalline silica, asbestiform minerals, heavy metals and dioxin. No asbestiform minerals are present and the crystalline silica, heavy metals and dioxin are all less than the maximums set by Federal and State agencies. The clay material was analyzed chemically for all major, minor, trace and rare earth elements. The geology, applications and analyses will be discussed in the paper.

Jan 1, 2005

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, 1998

By James G. Sack, Donald G. Wieland, James H. Meinholz

The paper will describe the $1.7 billion Milwaukee Program. Past contracting practices of the Milwaukee Metropolitan Sewerage District are discussed. To minimize costs and claims, the MMSD has implemented some recommendations from Better Contracting for Underground Construction. Currently implemented are: full disclosure of subsurface data including interpretations, the deletion of disclaimers relating to subsurface information, use of the federal Differing Site Condition clause, payment for mobilization. Also considered was the recommendation concerning Wrap Up Insurance. The MMSD shares and allocates certain designated risks through the Contract. A claims handling methodology has been developed and used on this major construction program.

Jan 1, 1983

By M. Sagisaka

Coal is expected as one of the main energy sources for a long period because of vast deposits. However, two large barriers to utilize it are suggested, i.e. the carbon dioxide emissions and ash disposal. The authors chose principal methods and areas to utilize coal ash and analyzed the environmental impacts caused by the ash treatment considering the source of the ash. According to the analysis based on lifecycle thinking, an optimized ash treatment system can reduce the integrated environmental impact. It suggests that coal can carry out its role for several decades without disturbances from the point of ash treatment.

Jan 1, 2006

By Graham G. W. Mustoe

Energy losses are important factors in a conveyor's performance and design. A significant energy loss due to belt sag within a conveyor system occurs when shearing motion between the bulk material particles occurs as the material moves along the belt. An initial analysis of these phenomena was performed using the discrete element method, which is a general-purpose numerical modeling technique for analyzing the mechanical behavior of particulate materials. The software used in this work was Overland Conveyor Company's, Chute Analyst Professional, a discrete element computer code designed specifically for analyzing bulk materials transportation and handling problems.

Jan 1, 2008