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By Dean J. Soderstrom

Soil and sands were contaminated with depleted uranium from weapons testing. This resulted in the formation of a complex mixture of uranium compounds. Characterization studies of the soil indicated the uranium was present as uranium metal, uranium oxides, silicon-bearing metallic uranium, and uranium silicates. A process was developed to selectively remove dense uranium compounds using gravity separation and a chemical extraction system to remove uranium which was not available for separation by gravity methods. Results from characterization studies and pilot scale testing are presented for background information. The primary purpose of this presentation is the report of the results achieved in the field application of the processes.

Jan 1, 1995

By R. G. Darmody

Chemical problems associated with surface mining, such as acid generating materials, are important and well documented. However, reclamation research has shown that poor soil physical condition is the most limiting factor to successful row crop production on reclaimed mined land. Critical to success are selection of the best available soil materials used in soil construction and a material handling method that minimizes soil compaction. Excellent corn and soybean yields have been achieved on low strength soils both in high weather stress years as well as low stress years. Total crop failures have occurred on high strength soils in years of weather stress. Some deep tillage practices have been successful in improving compacted soils, but it is preferable to avoid compaction when the soil materials are handled. Soil strength measurements with a cone penetrometer have proven to be a useful tool in evaluating rooting media and reclamation practices. Research has shown that surface mining can be a short term land use that may be followed by productive farmland, if reclamation is done correctly.

Jan 1, 2002

By E. H. Partelpoeg, B. G. Belew

In 1990, the Chino Smelter completed the construction of a plant designed to recover metal values and water from smelter scrubber effluent. Equipment was installed to maximize effluent recycling and minimize costs. The process utilizes magnesium hydroxide as a neutralizing agent which has the advantage of precipitating copper from solution with minimum generation of solid reaction products. The neutralized stream is clarified, with solids recycled to the smelter for metal recovery while the clarified effluent is recycled to the concentrator for use as process water.

Jan 1, 1992

By G. D. Naugle, L. C. Atkinson

Introduction Deep open-pit mines invariably affect the local and regional hydrologic systems. Pit dewatering, occurring during mining operations, puts an obvious hydrologic stress on these hydrologic systems. However, post-mining hydrologic impacts resulting from the pit refilling with groundwater following the cessation of mining activity can also be significant. The prediction of the rate at which the post-mining pit will fill with groundwater is a critical aspect of assessing the long-term hydrologic impacts. Numerical groundwater flow modeling provides a method for predicting the groundwater refilling rate of the pit. The rate at which pit "lakes" fill depends on several factors: •the rate and duration of pit dewatering; •the depth and size of the ultimate pit and •the pre-mining hydrologic regime. These factors can be incorporated into a detailed numerical groundwater flow model that can then be used to assess the effects of dewatering and post-mining recovery on the local and regional hydrologic systems. A sufficiently detailed, numerical groundwater model provides the oportunity to: •account for complex geology near the pit; •assess the impact of active pit dewatering and •predict the long-term impacts of post-mining groundwater flow into the pit. A detailed groundwater model incorporating these items has been developed and applied at an operating open-pit mine. Developed by Durbin and O'Brien (1987), the three-dimensional, finite-element, groundwater flow model was used to represent the hydrologic system of an approximately 253-km2 (98-sq mile) area surrounding the pit. Historical groundwater elevation data, stream flows and meteorologic, geologic and geophysical data were used to establish the dimensions and initial conditions for the model. Steady-state conditions, representing the pre-mining local and regional hydrologic systems, were simulated using the initial conditions incorporated into the groundwater model. The groundwater model was then utilized to simulate various dewatering programs, to predict the filling rate and the groundwater depth in the ultimate pit once mining activities are complete and to assess the long-term impacts on the regional groundwater flow system. Development of pit lake model Groundwater modeling efforts were completed in two phases. The first focused on pit dewatering activities, while the second phase concentrated on the post-mining effects on the hydrologic system. The final estimates of groundwater elevations calculated during the pit dewatering simulations were used in predicting the post-mining recovery of the hydrologic system. The groundwater model was also modified prior to the second phase to account for the volume of rock removed during mining activities. To account for the actual volume of rock mined, the geometry of the post-dewatering model grid was modified to approximate the final pit geometry. The depth and width of the ultimate pit were divided into eight idealized stages that represented significant changes in the bench geometries. These eight stages were then introduced sequentially into the model according to the predicted water elevations within the pit. In this way, changes in the volume and depth of water within the pit were accounted for through time. Once the ultimate pit geometry was accounted for in the model, it was necessary to assign new hydraulic characteristics to those parts of the model grid (elements) that represented excavated rock. The solution of the numerical model requires that finite hydraulic conductivity values be assigned to the portion of the groundwater model that represents excavated rock. Therefore, the calculated groundwater elevations differ, somewhat, between the edges and the center of the open pit. These model-calculated water elevations at the edge and in the middle of the open pit represent the elevation of water that would occur in the pit lake. To minimize the error in the estimated level of water within the pit lake, the hydraulic conductivity was increased to a value that would: •minimize the predicted difference between the groundwater elevations across the open pit and •produce a numerically stable solution. Specific storage is the hydrologic parameter that accounts for the water produced by compaction of the aquifer matrix. To predict the groundwater volume that would flow into the ultimate pit, this parameter was assigned a value equivalent to the compressibility of water. This value of specific storage reflects the post-mining groundwater storage occurring as an open body of water. Additionally, a specific yield of 1.0 was assigned to the pit elements to represent the 100% porosity of the open pit. In

Jan 1, 1994

By Charles E. Scott

The molybdenum industry has been in a depression since the beginning of the decade. Real molybdenum prices are significantly reduced from 1979-1980 levels when there was a perceived capacity shortage and continued expectations of burgeoning demand. Primary capacity brought on stream since then has been unable to operate profitably and indeed, in light of high inventories and reduced demand, has been largely unnecessary. Structural changes in the molybdenum industry will be needed in the future to weed out superfluous capacity and to expand demand through new product applications.

Jan 1, 1986

By Steven G. Vick, Herbert H. Einstein

1. INTRODUCTION The Tunnel Cost Model (TCM) is a computer based model whose objective is to quantify the risks of hard rock tunneling in terms of cost and time to completion. The main feature of the TCM is the simulation of the tunnel construction. The simulation makes it possible to incorporate in the time and cost computations the effect of uncertainties in geologic conditions and in productivity rates and costs. The cost and time computed with the TCM will be in form of distributions that allow a quantitative risk assessment. The TCM will be useful as an estimating tool permitting the estimator to rigorously relate uncertainties of individual factors to the end result. The TCM will also make it possible to evaluate technological innovations and to identify problem areas in existing technologies. The TCM consists of three interacting submodels: the geologic submodel, the construction operations submodel and the tunnel simulator. The goal of this paper is to describe the geologic submodel, whereas the construction operations submodel and the tunnel simulator will be described in the following paper by Moavenzadeh et al. First it will be shown how interactions between the geologic submodel and other parts of the TCM will impose certain requirements on the geologic submodel. These requirements, which relate primarily to the description of geologic conditions by a set of problem-oriented parameters and the quantification of uncertainty associated with geologic conditions, will then be discussed. This is followed by the description of the special structuring techniques -- decision tree and segmentation -- that are necessary to handle the great number of

Jan 1, 1974

By Andrew Griffiths

The emphasis in the title of this paper should be placed on the world "Total", since the detoxification of cyanide in its free and weakly-complexed form with H202 has already found application in many areas, including the treatment of mining effluents. One of the most common forms of cyanide found in gold-mill effluents is hexacyanoferrate (usually ferrocyanide), which is included in measurements of total cyanide but is too stable to be oxidized by H202 or any other conventional oxidizing agent. This has led to the view that H202 cannot be used to detoxify effluents containing hexacyanoferrates, when a limit has been set on total cyanide. A process is described in this paper which does meet this requirement, and which has already been demonstated in two Canadian gold mills. Before describing the new process, the terms "free", "total" and "weakly-complexed" cyanide will be defined as they are used in this paper.

Jan 1, 1998

By S. C. Sethi

The paper presents an analysis and discussion of the underground ventilation system at the waste Isolation Pilot Plant (WIPP), with particular emphasis on specific repository-related requirements and the gradual evolution of engineering designs relative to the WIPP Project scope. The underground facility has been constructed with three shafts. Additional studies, coupled with actual site-specific experience, have established? the need for construction of a fourth ventilation shaft to double the under-ground airflow. As a research pilot project, and the first of its type in combining mining and nuclear technologies, the WIPP Project is accumulating data and experience that may be fruitfully applied in the future designs of ventilation systems for planned commercial nuclear waste repositories.

Jan 1, 1988

By Edward S. Plotkin

The tunneling construction industry faces a new challenge in endeavoring to comply with the multitude of regulations and standards of the Occupational Safety and Health Administration and to work following accepted and experienced tunneling practices. Tunnel inspections appear to be gaining in priority. The national OSHA inspection activities reported for the year 1976 in the construction industry are as follows: 989 Inspections 45 As result of Accidents 186 As result of Complaints 605 General 153 Follow Up 34% Were found to be in compliance 714 Citations were Issued 1,825 Violations were found (201 of which were serious; 1573 were non-serious; 51 were imminent danger. There were no recorded failures to abate a violation in our industry.) The five general priorities by which a company would be scheduled for an inspection in descending order are: imminent danger situations, reports of fatal accidents or catastrophies, inspections in response to valid employee C( taints, inspections of work places covered by National Emphasis Program NEP, (OSHA's NEP has been designed to impact on any industry having a very high injury or illness rate) and finally random inspections of work places covered by OSHA. The following criteria in selecting companies for random inspections is used by OSHA.

Jan 1, 1979

By M. Gershon

The article is an excellent one, providing a basis for the conduct of the major tasks in underground mine planning and scheduling. I object to only one word. Since that word is featured in the title, it is a strong objection. The word used erroneously is optimization. There is no optimization performed in the article. By definition, an optimization is an approach that yields the best of all possible solutions. We can limit this definition to its narrowest sense, the optimization techniques of operations research such as linear programming, or broaden it to include less sophisticated search procedures that find the best mine plan or schedule. No such claim is made in the article. No optimization of any kind is performed. The major tool used is a simulation, which, in truth, is probably more appropriate for this problem than any optimization. But simulation does not optimize. It only allows for quick evaluation of many options, leading to the selection of the best plan "of those tried," not "of all possible plans." This article, of course, is not the first mining paper to make this error. It seems that the word optimization is used more to impress people than to refer to any act of optimizing. It is used in a way that implies "try to optimize" or "come close to optimize," but not to really do it. It is usually appropriate to quietly ignore this error. But when Dr. Chatterjee, who has done so much good work in true optimization projects and whose work I have come to admire, makes such an error, it is time to publicly dispute it. Having discussed this very point with him in the past, I am sure that he will agree. If he can support this position in his response, perhaps people will start to listen and we can reduce the number of false claims of optimization. This should be easy for him in this case since the approach he used, simulation, is the more appropriate one anyway.

Jan 1, 1987

In late 1993, Inco Ltd. completed a $600-million environmental improvement project at its Sudbury, Ontario operations -the largest single environmental project ever undertaken by a Canadian corporation. Efficient new facilities and innovative technologies installed during the course of the project have also significantly improved Inco's productivity and competitiveness. In early May 1994, a panel of 18 Inco authors contributed to a Technical Forum, "Environmental Programs at Sudbury," presented at the 96th Annual General Meeting of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) in Toronto. Their papers have been published in CIM's Toronto `94 Proceedings Volume, pp. 62-77. The following report draws primarily on discussions of Inco's milling and smelting operations published in the Proceedings Volume. The Proceedings Volume also includes papers on the acid and oxygen plants and on engineering, construction and commissioning of the project. The 222-page Proceedings Volume is available from CIM, $C27 plus shipping. To order, contact: V. Ward, CIM, Xerox Tower, 1210-3400 de Maisonneuve Blvd W, Montreal, Quebec, Canada H3Z 3B8; phone 514-939-2710, fax 514-939-2714. Lane White, Publisher.

Jan 1, 1994

By Jr. Gambrell

Support characteristics of in-cycle trusses are analyzed using a photo-elastic model loaded by tightening a truss in the sequence normally used in an underground mine. Stresses in the roof at its center point and at the junction of the roof and rib are examined. Effects of zero tension and unequal tension in the inclined anchor rods are presented. Effects of simulated subsidence on stress in the roof surface and on tension in the separate truss members are examined. Conclusions are drawn relating to (1) the effects of tension in the inclined anchor rods on uplift and compressive stress parallel to the roof surface, (2) the effects of subsidence on stress in the roof surface and, (3) the effects of subsidence on tension in the truss members.

Jan 1, 1989

By H. E. Goetzman

A cooperative research project supported by the taconite industry and the Minnesota DNR was undertaken to establish quality standards for carboxymethyl cellulose (CMC) based organic binders. The objective of this study was to identify the effect of CMC quality parameters such as degree of substitution, molecular weight, and purity as well as the effect of inorganic extenders such as sodium carbonate on performance. These factors have been evaluated by green-ball testing with two taconite concentrates followed by pot-grate tests. Balling tests with bentonite and Peridur were conducted to provide baseline data. At a constant DS the molecular weight as measured by viscosity had the greatest effect on green-ball drop strength. Dry-ball compression strength was most dependent on CMC addition rate and sodium carbonate content. DS was not found to have a major effect on green-ball quality for medium molecular weight CMC.

Jan 1, 1988

Steady state simulation has become a highly effective approach to the optimization of existing mineral processing plants and the design of new facilities. Accurate phenomenological models imbedded in user-friendly software packages make this advanced technology available to the mineral processing engineer. The new version 2.0 of the USIM PAC software package contains many improved features, and a new Windows 3 graphics interface. The main features include Objective-Driven Simulation, new fields of application, improved data processing algorithms and improvements in the design and optimization capabilities.

Jan 1, 1992

By A. M. Edwards

In many ways a government could be regarded as a macro business enterprise. Its shareholders are its peoples, the productivity of the nation depends on them, and, indeed, the profits or losses of a nation's balance sheet can be linked to the surplus or deficit in its balance of payments. International loans need to be repaid, and in most developing nations the noose is tied so tightly that one wonders if such debts will ever be repaid. In their endeavour to meet such obligations, their currencies may be devalued [sometimes in frightening proportions], in the hope of boosting the export potential. However, this is a vicious circle, since exports will not be achievable unless sufficient technical expertise and infrastructure exist to address the opportunities which may have been created through devaluation. Many of the poorer countries have exportable resources of minerals, which are supplied on the international market. This may be the good news, but, unhappily, steps were seldom taken to enhance the value of the mineral products through further beneficiation and the production of high-value sophisticated products. That is where the vicious circle comes in: inadequate infrastructure is created, competent and well-trained manpower is not generated, and the result has inevitably been that the GDP slips backwards, and the nation becomes progressively impoverished. To exacerbate the problem, it is unfortunate that the more impoverished a nation becomes, the greater is its birthrate, and hence the greater the need to create wealth at the very time that the nation is becoming poorer and poorer. Within this scenario, one may well reflect that this is exactly what nations on the African Continent are experiencing, namely exploding populations, although most of the poorest nations in the world are found on this continent. Yet they often possess a superior mineral production potential. Africa still suffers from what may be called the colonial influence, in that the developed world has regarded this continent as a source of raw materials to feed its own factories. The colonial powers gave only secondary attention to developing the nation's peoples and its infrastructure, such as railways, roads, harbours, and other services. These problems all naturally fall within the ambit of government interest, and it is therefore obvious that the state should play a dominant role in addressing them. The reasons for governmental involvement in mineral-related research and development differ considerably, depending on the state of industrial development of that country. Thus, in the highly industrialised world, government's interest will lie mostly in the fields of strategic minerals, which may not be economically exploitable. An example would be the exploitation of American low-grade chromites during the Second World War, or minerals which need to be imported from unfriendly or unreliable sources, such that disruption would not be in the national interest. Colonial powers like the United Kingdom and France established R&D facilities to assist, inter alia, in the exploitation of mineral resources in their colonies. The approach of developing countries would differ from that of the industrialised nations, in that their primary quest would be to promote, support and encourage the development of infrastructure, and the establishment of major industries in order to create and provide employment opportunities, as well as to support small operators who cannot afford to undertake their own research and development. On the debit side, it is a sad fact that, however good their intentions may be, underdeveloped countries are invariably unable to provide the requisite financial support to sustain their own research-and-development laboratories. In a high-tech world, the cost of sophisticated equipment is steep and cannot be afforded. Again, the proverbial vicious circle comes into play. The competent researchers find themselves without rewarding employment and would therefore shun such institutions. Recent trends in the developed world have been to privatise research-and-development institutions, the argument being that they should draw closer to the industry they serve, and that the provision of taxpayers' money for strategic purposes is no longer as important as it may have been once. Complete state withdrawal has had its negative effect in that long-range, high-calibre research has tended to be replaced by short-term problem-solving projects. Industries engaged in the minerals business differ somewhat from major ones, like motor, computer or pharmaceutical industries, which are large enough to support their own internal research and development, and whose work is highly confidential, so that any leakage could have disastrous consequences. Furthermore, private companies are answerable to their shareholders and costly long-range, 'blue-sky' research would be difficult to justify. Since mineral research has become of lesser importance in the sophisticated First World, this trend has persisted. On the positive side, R&D institutions which are totally financed by government, suffer because they tend to forget the reason for their existence. They have often become a form of auxiliary to an academic institution where higher degrees are collected by scientific boffins who, in their quest for academic excellence, tend to disregard the benefits that industry may ultimately gain from this research endeavour. The trend in recent years - and South Africa is no exception - has been for the state to progressively reduce its subsidy, whilst at the same time encouraging research organisations [for their ongoing survival] to interact closely with industry, and to conduct work directly for them on a contract basis. Organisations such as CSIRO in Australia, CANMET in Canada, the USBM in the United States and Mintek in South Africa all generate income from the private sector. However, the critical fact is that the State should never withdraw

Jan 1, 1995

By Felicia F. Peng, Lili Li

The dispersion model of nonideal flow was applied to describe the hydrodynamic state within the flotation column. Residence time distribution (RTD) data of a laboratory flotation column were measured to determine the parameters of the model. The effects of operating variables and column geometry on the Peclet number which reflects the extent of axial dispersion were investigated and a semi-empirical expression of Pe was formulated. The dispersion model was validated for the column flotation of ultrafines coal. Under the conditions of sufficient aeration rate and frother addition, a good agreement between the measured recoveries and predicted data was obtained. The dispersion model with first-order flotation rate process of the flotation column developed in this study is useful in predicting the collection zone recovery of fine coal, and for the flotation column scale-up.

Jan 1, 1995

By H. C. Verakis, T. E. Lobb

During the past decade, approximately 5 billion pounds of explosives were used annually in the United States. Most of this quantity of explosives was used by the mining industry, with coalmining being the dominant application for explosives. Considering the large amount of explosives used, the accident safety record for the mining industry has improved significantly over the past several decades. Although blasting accidents usually represent a small percentage of the total number of mining accidents, they continue to occur and the severity of these accidents is disproportionately high compared to the other mining accidents. This paper is an analysis and summary of mine blasting accidents over the past several decades as they relate to surface coal mine operations. A compilation and review of surface mine blasting accidents from1978 through 2001 was made. The accident data was examined to identify the trends and primary causes, which continue to be blast area security, fly rock, premature blast, and misfires. Approximately 46percent of the causes of surface coal mine blasting accidents are attributed to blast area security, while fly rock, premature blast, and misfires represented an additional 50 percent of the causes. Accident categories were established based on the cause of the accident or the activity that was taking place when the accident happened. A discussion of the accident data is presented to increase hazard awareness and to emphasize safe blasting practices and MSHA requirements concerning mine blasting operations.

Jan 1, 2003

By J. E. Brownhill

After being closed for three years, Specialty Minerals Inc.'s Port Inland limestone facility reopened in the spring of 1992 as a commercial limestone producer. In 1990, Specialty Minerals, a division of Pfizer Inc., bought Port Inland's reserves and equipment from Inland Steel because of the strategic value of the limestone for the production of precipitated calcium carbonate (PCC). Specialty Minerals' project team faced many challenges in reconstructing the Port Inland facility. Many traditions and norms had to be overturned to achieve the productivity, flexibility and cost necessary to survive in today's competitive minerals environment. Port Inland's history Inland Steel built Port Inland in 1930. It was operated as a captive source of metallurgical grade limestone for the steel industry until its closure in 1989. The facility is located in the Upper Pen¬insula of Michigan on the north edge of Lake Michigan. Operations consist of a deep water port facility with crushing, screening and stockpile storage for 453 kt (500,000 st) of finished product at the port. Ninety-nine percent of the stone is shipped by lake boat to ports within the Great Lakes. The operation is unique in that both metallurgical dolomite and limestone are produced on site.

Jan 1, 1994

By Chen Bingchen, Zhang Jian, Liu Jiaxiang

The influence of various installation angles of hydrocyclone on its operation indexes was investigated, and the correspondent mathematical models were established in this paper. The models developed in this paper can be used to the optimizing control of hydrocyclone and make the hydrocyclone as a particle size sensor.

Jan 1, 1995

By Jay Hilary Kelley

A ventilation system is described using dual aircourses: one zone occupied by working personnel, the other at the active working face. The two zones are separated by a partition or Shroud. The occupied zone to the rear of the face zone is ventilated adequately but with considerably less air because little gas, dust, or fumes are present. The face excavating zone is sealed and maintained at slightly more negative pressure preventing dust and gas generating from within to escape. Explosive mixtures within the face zone is rendered non-explosive by the introduction of inert gas therein. Each zone is vented separately to the outside of the mine. Because less total quantity of air is required for human breathing, etc, the total ventilation system can be drastically reduced in tan capacity, development entries, and air shafts, -- a great savings in costs.

Jan 1, 1991