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By J. C. Danza Errico

The bauxite deposits on the Pocos de Caldas Plateau in the state of Minas Gerais, Brazil, were formed by the differential weathering and leaching of alcaline rocks in a ring structure. Their action on steep topography formed heterogeneous ore posture and chemical grades. Variographic analysis of several of these deposits show nested structures that are probably related to ore genesis. Kriged ore reserves estimation are presented with emphasis on the data pro cessing method that was employed. Programs were written in APL. Its intrinsic use of matrices contributed to faster programming and less computer time. In many cases looping was eliminated. The high resolution graphic resourses of APL. workspace facilitated programming of variogram analysis, fitting, and regularization. APL sub-routines are presented for variogram calculation and kriging.

Jan 1, 1986

By Randal J. Barnes

In, any open pit mine the ability to make accurate production estimations for the shovel-truck system is an important asset. This is true in an operating mine wishing to estimate production under a set of system modifications (i.e. more trucks, fewer loaders, change in roads, etc.), as well as in the pre- mining planning stages of a property. Many different methods have been proposed for solving this problem; some of the methods rely heavily on "rules of thumb" while others are highly mathematical and require access to a high speed digital computer. Analysis of shovel-truck systems with the use of simulation models is a widely accepted technique within the industry. Through the use of such models it is possible to account for much of the inherent variability of the system and thus produce meaningful results. However, simulation studies are expensive. Formulation and setup of the actual simulation model requires a significant commitment of time and energy. In addition, the cost of the necessary computer runs is often of considerable magnitude.

Jan 1, 1979

By Jim Morris, Davin Ishii

The major source of water for Southern Nevada is Lake Mead. However, the existing pump station located on Lake Mead is inadequate for one of the fastest growing areas in the United States. In order to keep up with the increasing demand for water in Las Vegas, a parallel system is being constructed. The intake for this system is being constructed approximately 68.58m (225ft) below the surface of Lake Mead. The lake tap consists of installing casing and secant piles to support the shaft collar, excavating a 21.34m (70ft) deep intake shaft, and installing a3.66m (12ft) diameter steel liner.

Jan 1, 1999

By Jean Paul Duterque, Morris J. V. Beattie

In many parts of the world, pyrite and arsenopyrite occur together in sulphide ores either as the only sulphide minerals or in conjunction with other valuable sulphides. It is desirable to produce separate concentrates of the various sulphide minerals, including pyrite and arsenopyrite, so that the contained desirable metals can be recovered economically. It is common, for instance, for gold in an ore containing both pyrite and arsenopyrite to be associated almost exclusively with the arsenopyrite. It is desirable in this instance to produce an arsenopyrite concentrate for gold recovery while rejecting the barren pyrite.

Jan 1, 1992

By A. C. C. Pacheco, L. C. Bertolino, M. L. Torem

On account of geological characteristics, Brazil is a country of large deposits of high quality kaolin, with the larger ones being located in its northern region. In the last years, kaolin beneficiation and production area is receiving great investments, aiming at a high quality kaolin production to be used in the paper industry, mainly intended for the foreign market. After the conclusion of expan- sion programs and with the advent of new production areas, Brazil is very soon expected to come in second place in the kaolin world production ranking.

Jan 1, 1998

By A. F. Fossum, D. E. Munson

The U. S. Department of Energy is constructing and operating the Waste Isolation Pilot Plant (WIPP), a research and development facility near Carlsbad, New Mexico, to determine whether or not defense-generated high-level radioactive waste can be stored safely in bedded salt. The goal of the WIPP modeling program is to develop the capability to predict room responses from one site to another without a priori knowledge of the actual room responses. Data from one of the early WIPP excavations, called the South Drift, have already been used to form an initial evaluation of computational models for predicting room closures as a result of salt creep [Morgan et al., 19851. In that study, a significant unresolved discrepancy existed between predicted and measured room closures. It was suggested that future studies address alternate forms of the constitutive law. In this paper, an alternate form of the creep model for salt is used that is founded upon the deformation- mechanism map for the micromechanical deformation processes. This model embodies both steady-state and transient creep. Also, quasi-static plasticity is incorporated into the complete constitutive model for salt. The conclusion is drawn that the combination of the mechanistic creep model, plasticity, and flow potential can approximate the late time South Drift deformation. Further improvement of the model fit of plasticity in the future is expected to further improve the simulation.

Jan 1, 1986

By E. I. Jurgens, K. E. Hanney, D. C. Comrie, R. H. Fletcher

Introduction The reclamation of mine/mill tailings areas is undertaken for a variety of objectives including safety, appearance, economical use of lands and forests and long term storage of a future resource. The establishing of criteria for these objectives at any site is a shared task of the government and mining company. Our attention in this paper is directed to uranium mine/ mill tailings as they are handled in the Canadian industry and in the unique Canadian climate. We focus our attention on the state of the art. Uranium is a ubiquitous mineral forming an average of 4 g per tonne of the Earth's crust. Ores are mined at about 500 g per tonne so that the residual content of uranium in tailings is comparable to average background levels. However, as in most mine/mill operations, the ore contains other minerals that become readily mobile after milling operations. Thus the main objective of tailings impoundment is the stability both physically and chemically of the mobile materials. Since the requirements for the operation and construction of tailings areas in Canada have changed considerably over the past decade, there exists a great many mine/mill tailings areas which while considered adequate in their day, would not meet modern criteria. However, most of these installations pose no concern or hazard to the public. The proximity of mine/mill development to inhabited land areas has necessitated more stringent modes of tailings operations and provisions for tailings site reclamation. The more important of these have been: 1) the prevention of dyke failure, with large liquid-solid outflows onto adjoining lands, and 2) the prevention of seepage from the tails of pollutants such as chlorides, sulphides, heavy metals and radionuclides. Uranium mill tailings are discharged as a slurry from the concentrator after the removal of generally only about 1000 g, or less, per tonne of uranium from the as-mined ore. As a consequence, a great volume of low level activity waste is generated. The amount of tailings is expected to grow in quantity in the future even faster than the increase in yellowcake production, as the demand for energy

Jan 1, 1980

By George H. Schnakenberg

The application of automation and robotic technologies to coal mining equipment at the face offers improvements in worker safety and efficiency. The evolutionary introduction of autonomous, intelligent machines to perform the most hazardous tasks in underground coal mines may become a reality within the next 10 to 15 years. The US Bureau of Mines Advanced Mining Systems research program is developing the technology necessary to achieve this goal. This program consists of both core and applications re¬search that focus on the fundamental issues of sensor-based, computer-assisted, machine control technology. In the near term, the research is directed specifically to the computer-assisted control of present-day underground equipment. The immediate effect will be relocating equipment operators to a nearby area of safety. It is being performed in a manner that can make incremental improvements in safety and efficiency. The research is being performed closely with private, government and academic researchers in the miring, space, armed forces and factory automation and robotics research areas. It is a mixture of basic research, applied research and the application and adaptation of existing technologies from a multitude of sources.

Jan 1, 1990

By Leonard Harris

Since the end of the cold war following the collapse of communism, enormous amount of funds are pouring into the developing countries including investments by mining companies for the development of gold and silver mines. A great deal of these funds are destined for expenditure in areas riddled with bandits, terrorists and active and latent criminals bent on stealing the mine operators hard earned production on its way from the mines to markets. Brambles Security Services employs experts in the field of safely transporting gold and silver products under various alternatives and aimed at relieving the mine owners of this responsibility. This paper examines the various service options available.

Jan 1, 1997

By D. Kump

Barrick closed the Bullfrog Operation in November 1999.During its life, the Bullfrog produced ore from three open pit mines and an underground mine; 32,000,000 tons of ore were processed at the 9,000-ton per day oxide mill. The mill tailings were deposited in a 320-acre tailings impoundment. When operations ceased, an estimated 750,000,000 gallons of water remained to be removed from the tailings impoundment. During operation, the drain down water from the tailings impoundment was pumped back to the mill for reuse; since closure of the mill, the drain down water has been managed by a combination of passive and forced evaporation.

Jan 1, 2004

By Harold E. Goetzman, Blair R. Benner, Shaolin Zhong, Rodney L. Bleifuss

A commercial high pressure roller press (KHD 90125) was installed at the Coleraine Minerals Research Laboratory for testing in October, 1994. Pilot plant evaluation of the high pressure roller press has shown that it can be used as an alternative to the rod mill for the comminution of taconite. A series of pilot plant tests were run to compare roller press products to rod mill products in a simulated taconite flowsheet using magnet separation and closed circuit ball milling. Further investigation of a hybrid grinding system, roller press crushing followed by ball mill grinding, indicate that the combination may represent the most energy efficient system for taconite processing.

Jan 1, 1998

By Akira Usui

Ferromanganese crusts on topographic highs in the western Pacific Ocean are believed to be potential resources of cobalt, nickel and platinum. Earlier shipboard geological and geophysical studies by Japanese organizations have focused on mapping of distribution of thickness and metal contents of the deposits when estimating the total reserves. This paper summarizes our attempt to obtain more feasible data of distribution patterns and configuration of the deposits which are important parameters for resource evaluation at some seamounts in the South Pacific Ocean. Morphology of the seamounts and micro-topography of the sea floors are described using shipboard acoustic remote sensing, deep-tow sonar images, and TV/camera. [ ]

Jan 1, 2008

By M. M. Rajkovich, L. Adams, J. J. Zaluski, S. Gardner

In 1998, a group called Kentuckians for the Commonwealth filed an Administrative Petition with the Kentucky Natural Resources and Environmental Protection Cabinet to designate 8,903± hm2 (22,000± acres) on Black Mountain, which contains the state's highest point, as unsuitable for mining. A fast track legislative process was triggered that could have "taken" 91 Mt (100 million st) of coal reserves or, in the alternative, imposed severe restrictions on mining. Even with all parties represented by reasonable individuals, this process can be extremely cumbersome and expensive. The legal and technical preparation for this unusual hearing process as well as issues and strategies of the negotiated resolution are reviewed

Jan 1, 2002

By J. W. Craven, M. Katom, K. M. McCaffery

At Ok Tedi, ore type and SAG feed size distribution vary widely and frequently. This makes control of the SAG mills by application of the power/pressure relationship difficult. Power logic has traditionally been conservative due to power spikes associated with rapid size-distribution changes. A new expert system was installed in early 2000. The system incorporates multiple state fuzzy logic to deal with frequent and radical ore type and size variations, along with monitoring of motor temperatures. A short-term power spike no longer warrants immediate radical action. This has resulted in increased mill throughput and improved circuit stability. Key words: SAG mills, Mill control, Fuzzy logic

Jan 1, 2003

By W. F. Hahnert, T. L. Ward, K. E. Stoll, P. A. S. Ralston

Fuzzy logic is well suited to the control of non-linear, time-varying, and/or any system for which it is difficult to obtain an exact mathematical model. To design a good fuzzy controller, a thorough understanding of the desired process behavior is required. Many papers have suggested that fuzzy controllers are robust. If they are, it is reasonable to explore whether or not they respond better than conventional controllers to errors in the feedback signal due to imperfect measurement or sensor degradation. It may be the case that simpler or less expensive sensors could be used in some processes. The research presented here relies on an integrated array of computer programs that model and simulate (1) the process to be controlled, (2) common feedback instrumentation, and (3) both fuzzy logic controllers (FLC's) and conventional controllers. Various types of feedback sensor imperfections are imposed upon the system, and the performance of the two controllers is compared. Each controller is tuned to its optimal performance in response to a setpoint change using perfect feedback measurement.

Jan 1, 1993

By Richard P. Curtin, Madan M. Singh, Francis S. Kendorski

INTRODUCTION The use of roof and rock bolts to reinforce the strata is an established method of rock support in both underground and surface excavations. However, the need to drill a hole, extract the drill-rods, and then place the bolt is time-consuming and costly. This becomes even more significant if the bolting is repetitive and extensive as in coal mining. Though the main thrust of this development was directed towards coal mining, the basic concepts are also widely applicable to all excavations. The authors, therefore, feel that this innovation should be of interest in rapid excavation and in tunneling. In the case of coal mining, it has been established from past statistics that the roof-bolting operation is the most hazardous activity. This is primarily because of the operator being exposed to unsupported ground. It is evident that remote installation of roof bolts would markedly improve the safety of the operation, if accomplished more readily with self-drilling bolts rather than the conventional two-step variety operation. Thus, in addition to increasing productivity, this development can be considered to be a milestone towards further improvements. The objective of this program was to establish the technical and economic feasibility of self-drilling roof bolts for use in coal mines. It might be clarified at the outset that this work was, therefore, directed primarily at showing that workable self-drilling bolts with less cost can be developed, which could be effectively used in mines. It was not to fabricate a production model bolt.

Jan 1, 1979

By Brian S. Prosser, Ian J. Duckworth

With the trend in the coal mining industry pushing towards improved productivity and greater production, the number and size of longwall panels is increasing rapidly. The development and mining of large longwall panels causes unique problems in the provision of adequate ventilation at the working faces. Because of the transient nature of the longwall panel, and the difficult field conditions for ventilation measurements, detailed pressure and volume surveys are often not conducted around the longwall circuit. This is unforlunate because the highest resistance airway in longwall mines is typically the longwall tailgate, which frequently represents the only unregulated split in the ventilation network. This paper examines data collected from ventilation studies of longwall panels at nine mines. The variation in airway resistance, ventilating pressure and airflow is examined and compared with specific factors such as airway dimensions, ground conditions and support type used.

Jan 1, 1997

By Jeffery Leavy, Ken Davis, Kirk H. McDaniel

The Waste Isolation Pilot Plant (WIPP) is a United States Department of Energy facility located in southeastern New Mexico. It is designed for the safe disposal of transuranic radioactive waste in deep geologic salt beds. Westinghouse TRU Solutions, LLC, the managing and operating contractor, undertook a project to simulate the processes at WIPP in order to identify bottlenecks and optimize available resources. The activities simulated in the model included the receipt, processing and disposal of radioactive waste underground, the mining of new areas for future waste disposal and the transportation of salt out of the mine. The complexity of the processes and the interactive requirements between processes required the use of advanced modeling techniques. The simulation model includes a huge number of locations and path network node points, with movement to and from the locations controlled using parameters rather than explicit routing. Information for the timing and sequence of the mining and nuclear waste emplacement operations is brought into the model via spreadsheets. Arrays in the simulation model keep track of past and future events that occur. Routing to the multiple possible positions in the underground mine is done using attributes, and system functions within ProModel in order to allow for a highly flexible sequence of planned events and to reduce the level of effort in creating the ProModel processing. Considerable use of subroutines in the simulation model is utilized for parametric decision-making that is repetitive. This presentation describes the modeling techniques used to accurately simulate the surface and underground operations. The surface and underground operations are considerably different, thus they will be treated in their own sections.

Jan 1, 2002

By D. H. Y. Tang, S. S. Peng

Three-dimensional finite element modeling (3-D FEM) was performed to analyze the safety factors of stump pillars, 5.5 m x 5.5 m, under a cover of 63 m using the Modified Drucker-Prager Theory. The results showed that they were safe. This was substantiated by underground observations. But the safety factors predicted by three commonly used pillar design formulae showed otherwise. This paper discusses the modeling details and analyzes the difference between 3-D FEM method and traditional pillar design formulae.

Jan 1, 1987

By M. J. Virnig, B. D. Boley, G. A. Wolfe, J. M. W. Mackenzie

A flowsheet for the recovery of nickel and cobalt from laterite ores was developed. The flowsheet involves acid leaching followed by hydroxide precipitation of the metal values and then releaching of the hydroxide cake with ammonia. Investigations of the chemistry of extraction of nickel by LIX® 84-I and a developmental reagent, XI-84-IT, along with the physical properties of the organic phases are described. Based on these investigations, suggestions with regard to design of a solvent-extraction plant and operating conditions were made.

Jan 1, 2002