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By L. J. Dahl, S. E. Paulson, H. L. Kuhlman

To provide basic information on the processes occurring during in situ leaching, the US Bureau of Mines developed a geologic characterization research program. This includes laboratory experiments wing leaching apparatus that can accommodate whole core samples. Whole core experiments result in a higher proportion of ore mineral contact by the leach solution than packed column experiments. They also allow for the assessment of permeability changes taking place as the result of mineral dissolution, precipitation, and clay swelling within the flow channels of the rock. The leaching apparatus developed can be wed for either constant-pressure or constant- flow rate experiments and allows for the control of flow rate, pressure, and temperature during the experiments. Details of the experimental apparatus are presented, as well as preliminary results from the first series of experiments on an oxide copper ore from the Casa Grade, AZ area.

Jan 1, 1988

By L. Buckingham

Barrick Goldstrike Mines Inc. has embarked on a continuous improvement effort to ensure that Barrick Gold Corporation will retain its lead in the gold industry in years to come. The continuous improvement initiative is based on careful mapping of the key levers associated with each activity of business. The individual levers are then evaluated to determine their potential to affect the profitability and safety of the operation. The most promising are diagnosed for root causes. These root causes are then addressed to enhance benefits. Through a structured approach of mapping, brainstorming, evaluating and instigating change with follow up measurement and reporting; Barrick Goldstrike is anticipating an increase in throughput at the autoclave facility of 10% with little or no capital expenditure. The resultant approach to Continuous Improvement will be utilized throughout the Goldstrike facility and then throughout Barrick's world-wide operations.

Jan 1, 2002

By P. Tsang, S. S. Peng

Mine floor failures, such as floor heave and floor buckling, occur frequently in underground coal mines where soft mine floor exists. The types of failure can usually be classified into two categories; shear punching failure and tensile failure. A model based on the Winkler's elastic foundation is proposed in this paper for floor stability analysis. The model considers material properties of floor strata, in-situ horizontal stress, pillar size, entry width, and configuration of multiple-entry system and predicts stress conditions in the mine floor based on given in-situ mining and geological conditions, as well as deformation of the mine floor. This information is used to predict possible failures of mine floor by comparing the strength of mine floor with its stress condition. The validity of the model is verified by in-situ data described in this paper.

Jan 1, 1992

By P. Mousset-Jones, F. Calizaya

Currently, a 4.3 km long drift is being developed on the 3440 level in the Lower Kalamazoo project at the San Manuel Mine, Magma Copper Company, AZ. The drift, located at 1050 m below surface, is being constructed using a 4.6 m diameter tunnel boring machine (TBM). The drift is ventilated by a forcing type auxiliary ventilation system. At the face, to mitigate the impact on the work environment of the TBM, the system is equipped with dust extraction and refrigeration systems. Recently, to evaluate the ventilation conditions in the drift, a continuous monitoring system has been installed. The system can be used to measure the air velocity, barometric pressure, relative humidity and air and rock temperatures. This study describes the capabilities and limitations of this system, and presents a summary of the results.

Jan 1, 1995

By Don Minard

Management support systems are extremely important to mining management to enable them to operate their company as a business. Management must give attention to the financial, maintenance, materials, and other reporting and control systems that are necessary to successfully operate a mining company. This subsection describes the management support systems that are critical to most mining companies. In this introductory review, the major objectives and functions of these management support systems will be introduced. The following topics will expand on the functions and key concepts as well as other considerations in each of these systems areas. Additionally, this introductory review will touch upon the unique environment that mining companies find themselves in from a management and personnel standpoint and the effect of this environment on management systems. Additionally, specific keys to successful systems installations and acceptance in the mining industry are discussed.

Jan 1, 1979

By J. F. T. Agapito, C. E. Brechtel, M. E. Adam

Full-scale stopping and simulated over- cast structures were constructed in large opening (30 ft high by 55 ft wide) room and pillar excavations in an oil shale mine. The program was undertaken to develop construction techniques and to generate data on structure costs and leakage rates. Leakage rates were measured using both sulfur hexafluoride tracer gas and "brattice window" methods at varying differential pressures. The measurements were conducted before and after a full-scale face blast to characterize the effects of blasting on leakage, and blast air pressures were measured across the stoppings. The operating performance of different combinations of permanent and temporary stoppings was evaluated by developing an operating model for a two-panel oil shale mine. The operating performance for the different stopping combinations was then compared to the system cost to evaluate the overall performance.

Jan 1, 1987

By E. S. Peterson, M. K. Harrup, K. A. Dolbeare, J. E. Wey

Efficient methods for the removal of copper from heap-leach solutions without mobile organic phases are a current mining industry need. To satisfy this need, a selective, high-capacity, durable solid material is required. The Idaho National Engineering and Environmental Laboratory (INEEL) developed a set of materials based on current solvent-extraction chelates that provide selective copper concentration in the presence of high concentrations of iron. In contrast to conventional solvent extractions, the author's strategy anchors the chelators to a nonpolymeric solid substrate through the use of a custom-designed linker molecule. The fundamental synthetic routes to these materials have already been established, and attachment to the solid surfaces have been achieved in an efficient manner. The author's continuing research is focused on the optimization of the synthetic pathways to these solid materials and the evaluation of their copper-capturing capabilities.

Jan 1, 2003

By L. M. English

A basic model was developed to help assess methane control needs for the longwall mining of coal in gassy areas. Rather than depending on reservoir and rock mechanical theories, it uses an empirically determined gas emission rate as an input, and it operates on the assumption that, within a specific region and zone, gas emissions will be relatively equivalent for uniform incremental volumes of gob created by mining. The computer program divides longwall panels into segments, keeps track of the face advance and generates emission rates and volumes for both the entire panel and for individual zones within the panel by summing values for all undermined segments. This model can aid in the determina¬tion of the number, size and location of vertical wells or other methane-control applications that are needed for gob gas control.

Jan 1, 2000

By Wojciech Suwala

The transition from centrally planned to market economy affects methods of economic analysis. The models which were used in the past are riot valid presently, however they we're the seed which initialized the development of methods and applications. There is more than twenty years of experience in modeling of coal mining development. The first attempts were devoted to select the moment of mine construction commencement in order to meet planned output. In Poland significant development of such models began in 1986. Within the Central Research and Development Program there has been a continuous development of models. These models from econometric to optimization ones, were a certain sequence which, in accordance with changing economy system, led to the last version of the model. It is the most suitable one for contemporary problems of coal mining in present Polish circumstances.

Jan 1, 1992

By H. E. M. N. Moursy, M. N. Ahmad, C. R. Holland, G. M. Walker, R. D. Chandler

This work describes the effect of process parameters on the acidulation of Moroccan phosphate rock using nitric acid, i.e., the nitro-phosphate process. A series of bench scale experiments were conducted, using a stirred tank reactor (STR) system, to investigate the chemical reactions involved and optimum conditions for the formation of nitro-phosphate fertilizer. The effect of reaction time, temperature, mixing speed, acidulation ratio, and acid concentration were investigated, and were found to have an effect on the dissolution of P2O5 from the phosphate rock, using nitric acid. An increase in nitric acid concentration resulted in an increase in P2O5 dissolution, however, the dissolution was also found to be a function of acidulation ratio. A nitric acid phosphate rock ratio of 4:l ensured 90% dissolution for nitric acid concentration > 30%.

Jan 1, 2002

By K. Kavouridis

On 30 April 2004, a large scale slope failure incident occurred at the external waste dump facility of the South Field Mine, in the Western Macedonia Lignite Center, Greece. This landslide involved the mobilization of waste overburden material (that was continuously deposited for the last 20 years) in the order of 40 Mm3, while the material that moved outside the boundaries of the waste dump was in the order of 3 Mm3. The factors that led to failure as well as the procedures and measures taken in order to stabilize the failure and resume normal operations at the South Field Mine are presented and discussed. Emphasis is given to the impact on mine operations and the cost related to resuming of normal production operation as well as to implementing important modifications and improvements of the materials handling system.

Jan 1, 2006

By S. K. Nandy, K. F. Unrug

The behavior of the immediate shaly roof within a drift mine in eastern Kentucky, operating in the Coalburg seam, was monitored with roof bolt dynamometers. The dynamometers used were capable of providing readings up to a maximum load of 66.72 kN (15,000 lbs), + 0.022 kN (5 lbs). To observe the influence of moisture on the rate and extent of roof deterioration, 57dynamometers were installed on roof bolts anchored in intake and neutral airways. Monitoring was conducted during the period January 1985 through January 1986, in order to cover a full cycle of dry and wet mine conditions associated with seasonal changes. Analysis of the data showed a trend of roof deterioration induced by condensation and eventual penetration of moisture within the immediate roof bedding planes, leading to rapid disintegration of the mine roof.

Jan 1, 1987

By Patrick R. Taylor

The hydrometallurgical fundamentals review did not arrive in time for publication in the May issue. Papers presented at the SME Annual Meeting, in Phoenix, AZ were available as preprints. The EPD Congress 1992 from The Metallurgical Society had several papers related to hydrometallurgy. Minerals Engineering 1992 was published in Minerals Engineering and contains several papers related to hydrometallurgy. In addition, a conference was held to honor Ernie Peters. The proceedings contains a large number of hydrometallurgy papers. Precious metals Gold extraction in the potassium cyanide-primene JMT sulfate-Xylene system was studied by Caravaca and Alguacil (Hydrometallurgy). Adams, Friedl and Wagner presented results on the mechanism of gold cyanide adsorption onto activated carbon (Hydrometallurgy). Adams also studied the adsorption of silver cyanide and used an IR method to evaluate adsorbed aurocyanide species on activated carbon (Hydrometallurgy).

Jan 1, 1993

Ravensthorpe Nickel Operation (RNO) is a major new mine and processing plant currently being constructed by BHP Billiton in a ?green field? site near the small town of Ravensthorpe, about 150 km west of Esperance and six hours drive from Perth in Western Australia. Ensuring that the project has a positive overall impact on the surrounding region and that this extends well beyond the life of the operation will be a major challenge for RNO, state and local government, and the local community. For the last two years, the Centre for Social Responsibility in Mining (CSRM) has been assisting RNO management and the RNO Community Liaison Committee to develop a community sustainability monitoring framework for the project. This paper reports on the process that was used to develop the framework, describes the main elements and briefly discusses key learnings from the exercise.

Jan 1, 2007

By P. C. O. Chukabarah

Atkinson's resistance square law is the cornerstone equation for traditional expression of energy losses in mine ventilation engineering. But the nomenclature for the various forms of energy losses are often confused for one another, misapplied or misinterpreted. These forms of energy were re-examined from thermodynamic and fluid-dynamic perspectives. Resultant expressions showed that both incompressible and compressible flow regimes in underground mines can easily be accommodated. Given the well-known three major energy forms, which are equivalent to one another but numerically unequal, corresponding equations to Atkinson's (pressure loss) for headloss and workloss were derived. The thermodynamic weight relational resistance ([w] s2/m5) associated with energy per unit weight (headloss) was dimensionalized for the first time. Also, normalized Atkinson-like equations for headlosses and worklosses were derived to ease direct computations in mine ventilation practice.

Jan 1, 1995

By B. K. Mishra, Partha Chakroborty

Jigs are the most important equipment used in the separation process that exploits the stratification of particulate matter under the influence of hydrodynamic and gravitational forces. Very little is known about the determined mechanisms by which particles of varying density, size, and shape stratify in a moving bed. A model is developed by using the discrete element method to understand the behavior of jig bed. This model is utilized here to study the stratification behavior of the bed and its control. The control action is based on the understanding of the physics of the stratification process within the framework of fuzzy logic. The actions suggested by the fuzzy logic controller (FLC) depend on the current degree of stratification and the existing frequency of the jig cycle. The results show that the FLC achieves efficiency in stratification with minor variations to the jig cycle.

Jan 1, 1995

By R. J. Manser

A mathematical model of a shaking table is being developed, for inclusion in a package for the simulation of gravity concentration. The general form of the modules and how they fit into the package is briefly described. The separation on a shaking table is controlled by a number of operating variables and the importance of these variables in the model development is discussed. The influence of wash water, feed pulp density, deck slope, deck amplitude and mass feed rate are reported. The form of the model is described being based on the probability of a particle of defined size and density reporting to a specific discharge site. The mathematical relationships which relate size and density distributions to variations in the operating parameters are presented. The use of these functions in the prediction of the performance of a shaking table is outlined.

Jan 1, 1986

By Klaus Schönert, Martin Botsch

In common high intensity magnetic separators, the magnetic particles are deposited on ferromagnetic matrices, such as expanded metals, steel balls or grooved plates, inserted into a strong magnetic field. The nonmagnetic material is flushed through the matrix chamber. Discharging the magnetic particles is only possible if the magnetic field is reduced to zero (e.g. high gradient magnetic filtration for the purifying of kaolin) or the matrix chamber is moved out of the field by a rotor (e.g. the Jones Separator). Therefore, these separators perform only in a batch or semicontinuous mode. A real continuous operation requirs transport of the deposited magnetic material to an outlet where it can leave the separation chamber inside the field. One possibility for accomplishing such separation and transport is through the use of a rotating induction body with a certain shape, such as a spiral.

Jan 1, 1995

By Robert L. Bonomi

One of the major operating costs for any labor-intensive operation is that of its employees' wage and benefits package. Today's packages are extremely complex, with multiple pay rates for different grades and shifts, intricate bonus criteria, and expansive benefit packages that include all sorts of medical, dental, pension and other costs that can be "hidden" from direct examination and consideration. The problems of estimating the total cost of such a package to a company becomes even more acute at negotiation time, when pressure from both sides to settle intensify and changes to package offers come rapidly. A comprehensive system is needed that can evaluate these costs and perform sensitivity analyses, on the various components of an agreement so as to aid in the solving of major labor deadlocks, productivity problems, and cost impacts created by those agreements.

Jan 1, 1982

By Val Ness, Leonard Harris

Mentoring is defined as close counseling by an experienced and objective advisor within the industry. It is one aspect of attracting the best candidates into the minerals industry, holding their interest, and encouraging stable career growth. By encouraging proper mentoring practices, we foster strong careers, we transmit important wisdom to the next generation, we fortify the industry with better talent, and we encourage the best possible advocates for the minerals industry. This paper illustrates the consequences of poor mentoring, offers an example of positive mentoring practice at the college or university level, reviews some guidelines for stable and fruitful mentoring, and proposes a plan to spread appropriate mentoring practices. Authors' note: The use of masculine pronouns is for convenience and simplicity only. Our best engineers and managers come from both genders, and the authors intend no slight to either one.

Jan 1, 2001