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By Finn E. Bronner

HISTORICAL PERSPECTIVE "Blessed be the Lord my strength, which teacheth my hands to war and my fingers to fight." Thus sang David three thousand years ago, in tacit acceptance of the condition of war, and in praise of the exceptional military skills with which this warrior king of Israel was endowed. He had cause to exult, for he had consolidated King Saul's conquests and added new ones of his own, not least of which was the capture of Jerusalem. David revealed in this operation that his mastery of the military arts embraced not only the weaponry and tactics of his day, but also strategy and that oldest of intelligence techniques: spies. The Jebusites, who built Jerusalem, had encompassed the city with the first of its many walls, but had neglected to incorporate the sole reliable water supply within its perimeter. This was Ain Gihon, today called the Fountain of the Virgin, which bubbled out on the east slope of Mount Ophel, one of the ridges on which Jerusalem was built, and drained eastward into the Kidron Valley. Water was brought into the city in the traditional manner: by women descending the stony trail outside the wall to fill their jars at the spring. But this essential daily activity was vulnerable to interruption by a hostile force outside the walls. To remedy this weakness, the Jebusites had driven a gallery from the spring a short distance into the water-bearing limestone under the city, and there cut a small collecting basin in the rock, a common way to develop springs throughout this arid region. But then the Jebusites dug a small vertical shaft from the roof of the gallery above the cistern upward about 15 m. From the upper end of this shaft, they constructed a narrow inclined tunnel with rock-cut steps leading up to the city streets. Thus the water supply could be reached even in time of siege.

Jan 1, 1979

By Anshumali Gangwar

This paper outlines the chance constrained binary integer program developed by the author in his doctoral dissertation at Columbia University, New York, 1973. The optimum planning of a mining program involves the determination of a production schedule which maximizes the net present value of the mining property. The actual mining process has an inherent stochastic and discrete nature. In particular, the demand for the mined product and the grade of the mineralized material in the ore are the two most important stochastic mining variables. The decision to mine or not to mine any block of a mining property is a binary integer variable. This paper outlines the formulation of pit production scheduling problem as a chance constrained binary integer program. The deterministic equivalents of these chance constraints are nonlinear in binary variables which have subsequently been linearized. The planned objective is to meet with a stipulated high degree of reliability, all the random demands as they materialize with a random supply of the commodity being marketed as determined by the eventuating random grade values of the exposed ore blocks and the mining system's production constraints such that the discounted total production costs over the entire planning horizon are minimized or the profits maximized. The emerging surface of the mine in each scheduling period is determined by the values taken by the binary decision variable associated with each block of material in each scheduling period.

Jan 1, 1982

By Charles G. Weakly, Alan M. Lander, Pamela B. Zohar, Robert W. Leonardson

The cluster of gold deposits at the Goldstrike property is located in the Northern Carlin Trend in northeastern Nevada (Fig. 1). At many mature mining camps like Goldstrike, exploration innovation and success may wane with time. In this regard, sufficient exploration drilling was conducted in the area immediately north of the ultimate pit crest and under the final planned pit wall to test for a major deposit. No indications of large deposits were found, however, the majority of drill holes did intercept mineralization. Mining along the northern pit wall exposed significant structurally controlled ore-grade mineralization that had been missed by exploration drilling. In 2002 and early 2003, the mine geology group added reserves to the pit and improved the definition of underground resources by targeting specific ore-controlling structures within favorable stratigraphic units by utilizing relatively inexpensive horizontal RC drilling from the pit wall. The widespread occurrence of mineralization to the north of the pit was re-interpreted to be an indication of continuity of these mineralized zones. In January 2003, 70 feet of 0.332 opt Au at a depth of 710 to 780 feet was intercepted in a dewatering well. This intercept was significantly thicker and higher-grade than average for the area, which confirmed the existence of high-grade structural continuity, and helped secure management support for additional exploration. A timely and cost effective solution was needed to confirm the potential of the area. Immediate follow-up drilling on tighter grid spacing was rejected in favor of improving the geology model. Exploration across the property would benefit from an improved geology model, but to provide results in a timely manner, the area to the north of the Betze pit was chosen as a starting point (Fig. 2).

Jan 1, 2005

By David V. Fitterman, David L. Campbell

We've used direct current resistivity (DC), electromagnetic (EM), induced polarization (IP), and ground-penetrating radar (GPR) geoelectrical methods to study mine dumps. The results reflect lithology, pore water saturation, and dissolved solids in the pore water. If the pore water has a pH less than 5, conductivity maps can indicate acid generating potential. IP measurements can help distinguish mineralogy in mine dumps, especially concentrations of sulfide minerals. EM and DC can help locate acidic/high TDS groundwater associated with mine dumps. GPR methods failed at the sites we studied in the West. Our own conclusions are augmented by those from the recent literature.

Jan 1, 2000

By Norman Weiss

The purpose of this paper is to relate progress in the engineering field called Minerals Beneficiation to undergraduate and graduate education in our colleges and universities. So mach has been written recently about the education of scientists and engineers that I've had to struggle against the temptation to repeat what has been often said before, particularly because man like Robert Mehl of Carnegie Tech, Antoine Gaudin of MIT, H. M. Davis of Penn State, and John Vanderwilt of Colorado School of Mines have recently written many quotable paragraphs on the subject. In the matter of progress, the rapidity of proliferation in the area of physical and chemical beneficiation is convincing proof that this is indeed a lively art, and having been a millman for 35 uninterrupted years I prefer to lean on personal observations to some extent, rather than on statistics and charts v culled from the journals. I propose in this paper to talk first about the progress we've made in our branch of the mining industry in the last 3 decades--particularly in the last few years--and try to show that future progress will depend upon the quality of education and capacity for research possessed by our colleges. The second part will deal with some of the problems the colleges encounter in trying to fulfill these responsibilities.

Jan 1, 1959

By J. Mark Richardson

Steady-state flowsheet simulators for mineral processing plants have evolved to a current high level of utility and accuracy. Reliable, general-purpose, semi-empirical models now exist in nearly all unit operations categories particularly in the areas of comminution and classification. .These models, installed as user-selectable functions within the integrated frame- work of flowsheet balance-solver software systems, can be strung together to represent any plant configuration. In addition, CAD-like graphics, data reconciliation and model parameterization functions have become standard features of the current generation of integrated plant simulators. These advances have given engineers the capability to investigate many different plant scenarios while requiring a minimum of actual plant testwork. This paper describes a methodology and an integrated software package which are being successfully applied in a number of operating plants worldwide to predict plant performance under changing conditions. Those conditions which can be changed include effect-of ore type, feed size, water addition rates, equipment geometries and flowsheet modifications. By using data from actual plant optimization exercises in real mills, the paper illustrates and out- lines a technique which includes plant data collection, ore breakage testing, flowsheet simulation, model-fitting (parameterization), data adjustment and model experimentation. Brief descriptions of some unit operations models, such as autogenous mills and cyclones, are provided as examples of the current state of such models. Ore breakage testing and its relation to certain models is also discussed. Computer- generated size-distribution graphs, along with tabular data generated by the simulator, round out the presentation and serve to demonstrate the real- ism and accuracy of the models. The paper concludes with a partial list of cases where this technology has been successfully applied.

Jan 1, 1992

By M. Charles Gilbert

Basement rocks in southern Oklahoma are divided into two groups. One group is the Lower Cambrian Wichita Igneous Province, a diverse igneous suite that crops out in the western Arbuckle Mountains and in the Wichita Mountains. These largely bimodal igneous rocks were emplaced in an intracratonic-rift environment. The other group, the older, is a set of Precambrian rocks of the Eastern Arbuckle Province, yielding ages between 1,350 and 1,400 Ma, exposed in the core of the eastern Arbuckle Mountains. These are deeply eroded mesozonal granitic rocks and associated granitic gneisses cut by numerous dikes ranging in composition from diabase to rhyolite. The southern Oklahoma igneous rocks have long been utilized mostly as dimension and crushed stone. Most of the early quarries were in granite of various red hues for monuments and facing stones. Large crushed-stone quarries are now exploiting both granite and rhyolite, which is used chiefly as aggregate and railroad ballast. The exposed basement rocks in Oklahoma represent an underdeveloped and accessible resource.

Jan 1, 1999

By G. Brooker

The back-filling operation at Olympic Dam mine supports a 9.8 million tonne per year (Mtla) underground Longhole Open Stoping operation. It involves a combination of Cemented Aggregate Fill (CAF), Surface Rockfill and Underground Rockfill. The fill material is introduced from the surface via bore-holes into the top of the stopes. Due to the deleterious effects of the dust and the thickness of the atmosphere in the stope it is not possible to view the filling process. The need for a means to measure the filling process is driven by the stopes, which have both rock and CAF fill placed in them. The large volumes and high relative cost of CAF makes the minimization of CAF fill a business priority. Incorrect filling can lead to the sterilization of ore reserve. The use of millimeter wave radar to view through the haze to give real-time data on the relative positions of the different fill masses is being developed as an in-stope fill control device. This paper reviews the salient points of the technology and its potential use in the back-filling operation at Olympic Dam. The broader potential of this technology for use in the mining industry by 'seeing' through water and dust laden environments such as that found in stopes and ore passes is discussed.

Jan 1, 2001

By Karel SPIRKO

The one-dimensional mathematical model of unsteady-state heat conduction through semi-infinite homogeneous and isotropic airway walls with convective heat and moisture transfer between their wet or dry naked surfaces and mine air with time variable temperature and humidity has been developed on the basis of introduction of acceptable simplifications of description of heat and moisture transfer between rock mass and mine air. The analytical solutions for computation of the temperature distribution and surface temperature of the airway walls and floor and for calculation of water vapour pressure near the wet surfaces at given time are obtained by means of the model presented. The presented solutions are derived for general conditions and they could be easily adapted to the actual ones. Results of the model represent basis for balancing heat and moisture transfer between mine air and its surrounding in deep mines under time variable temperature and humidity of the air and enable us to solve complicated dynamic changes of mine air temperature and humidity in an airway system by relatively simple mathematical tools. INTRODUCTION The importance of unfavourable influences and the costs of condition arrangements increases with mine depth. Precision demands on the methods which predict the environmental condition changes and by which it is possible to optimize condition arragements are still increasing. Environmental conditions in deep mines are determined especially by flow velocity, barometric pressure, temperature, and humidity of mine air. Therefore new and more exact mathematical models of mine air flow through airway system and those of heat and moisture transfer between mine air and individual important sources of heat and moisture are developed. The paper presented deals with description and solution of problems of heat and moisture transfer between mine air and airway walls as the rock mass is one of the important heat and moisture sources in deep mines. There are several different approaches to the problem. In some models the moisture transfer between mine air and airway walls is not considered at all. In other models the moisture transfer is described only by certain empirical coefficients. Simultaneous heat and moisture transfer is described seldom. This paper tries to describe in a simple way simultaneous convective heat- and mass-transfer processes taking place on wet naked surface of airway walls by means of corresponding

Jan 1, 1993

By J. H. Tylczak, R. Blickensderfer

Impact and abrasion properties of various commercial US grinding halls were evaluated and compared by the Bureau of Mines, US Department of the Interior. Laboratory tests were conducted on balls obtained from eight major US manufacturers. The halls included forged steel, cast steel, and alloyed white cast iron and were subjected to repeated impacts until they broke or until 300,000 impacts were exceeded. Pin abrasion tests also were conducted. The results showed wide differences in impact lives, ranging from a few thousand to over 500,000 impacts. The life of inferior commercial halls was increased five to six times by a laboratory tempering heat treatment. For halls that did not break, the major impact wear mode was spalling and ranged from an average rate of 0.28 to 4.46 mg per impact. The softest halls (steel) had excellent impact resistance but low abrasion resistance. The abrasion resistance of the steel halls generally increased with hardness. The alloyed white cast irons had about twice the abrasion resistance of the steel halls. Users should become aware of the wide variations among commercial halls, and ball manufacturers should be aware that their product can he improved.

Jan 1, 1990

By Lennart Malmqvist

Decision-making in exploration deals with experience, knowledge, and sometimes faith, but very often financing and profit, mineral resource aspects, employment, and general political ambitions are parts of the scene. At one end of this spectrum, there is the prospector and his decision on the actual project. The exploration business now expands from its pioneering phase for the benefit of a single company to a wider spectrum which includes the benefit of the large mining consortium and a national development program. Its objectives are also to maintain employment and to favor long-term stability in a mining district or a mining company. The prospector then has new aspects and questions to consider such as, what to do in mining districts where there is a shortage of ore resources but there are still useful investments in mines, processing plants, etc. To analyze the exploration process, therefore, seems to be of great importance in a time of rapidly changing conditions. As in other areas of complex decision-making, for example, in the fields of investments, of production, and of the armed forces, computers most certainly have an important role to play in future exploration decision-making systems. However, we must first analyze our own business as closely as possible to find out what kind of information we need, i.e., why we recommend an exploration program as a good or a poor one. An important part of the debate about exploration is the case study. Case studies on exploration are few and most of those written are only about successful exploration programs. Where are the case studies of the failures and the not so successful programs? Every prospector knows that the majority of exploration projects fail. Consequently, the most important experience seems to be hidden in the failures.

Jan 1, 1979

By Sunil Jain, Jan M. Mutmansky

As coal mining evolves in this country, underground coal is being mined at greater depth and under more difficult conditions than in the past. At the same time, economic conditions make it necessary to mine more efficiently and economically. As a result, pressures on mining companies arise on two fronts and make the job of mining coal underground very difficult. Recent improvements that have been made in health, safety and productivity have come about primarily due to improvements in existing technology and better management of all the production resources. However, this trend can continue only so far and thus innovation will be needed to continue the improvement. This paper deals with a concept that, on the surface, appears to be more efficient in terms of the costs to provide ventilation. The resulting design is oriented toward increasing the ventilation efficiency through use of a unidirectional ventilation plan but it also promises to increase recovery and decrease the requirements for development entries. To analyze this ventilation concept, two mine layouts with a similar production schedule were planned in a hypothetical 1.83 m (6 ft) coal seam. The first alternative analyzed uses a traditional approach to ventilation with centrally located shafts and a bidirectional ventilation pattern. Using this system, it is necessary to use large-diameter shafts and a large number of main entries. Using the same assumptions on ventilation requirements, the second alternative utilizes unidirectional ventilation whenever possible, a smaller number of main entries and small-diameter blind-bored shafts in the bleeder areas. The comparative analysis is performed using PSU/TDMVS, a computer network analysis program that is capable of determining the ventilation power requirements at any time in the mine life and converting the costs to a present value. The economic analysis is then completed by including the shaft-sinking and entry-driving costs and the costs associated with the recovery of coal that are directly related to the change in the ventilation system. The results are summarized on a present-value basis.

Jan 1, 1987

By George A. Takach

The U.S. Bureau of Mines is conducting research with the goal of automating underground coal mine roof bolters for greater mine safety. In the project described here, the Bureau has focused on automating the drilling portion of the drilling and bolting cycle. A drill monitoring system designed and developed by Parvus Corp. of Salt Lake City. UT, was placed on a Bureau model roof- bolting drill. The drilling parameters of torque, thrust, rotation rate, penetration rate, and position are monitored through sensors connected to an asynchronous, control-oriented local area network (LAN) that communicates with data-accumulating and data-processing nodes. By placing microprocessors at the two data nodes and at the valve control nodes, and combining these nodes with a personal computer (PC), the monitoring and control system can achieve parallel processing capabilities. Such capabilities are referred to as locally intelligent distributed processing. Only data that have changed significantly are reported through the LAN to a supervisory control and data acquisition (SCADA) system mounted on an IBM- compatible 80286 PC. The SCADA system displays the values of the drilling parameters and calculates the specific energy of drilling, which is then used as an indicator of the type of rock being drilled. Besides monitoring the drilling process, an operator at the computer can control the rotation and thrust of the drill from a remote location through the SCADA program and can set drilling parameters on the basis of observed values of the specific energy of drilling.

Jan 1, 1992

ABB Industrial Systems is one of the largest electrical engineering companies in the world. ABB develops, manufactures and markets electric drives. The company has more than 100 years experience in the application of medium- and high-voltage AC machines. And ABB's continuous research and development program ensures that its machines use the latest technologies and materials. Each motor is custom designed to meet specific applications. The HXR high-efficiency motors (100 to 1,900 kW or 134 to 2,250 hp at 50 Hz) are efficient and have low noise levels. Typical applications are pumps, fans, blowers, compressors and pulverizers. The enclosed units are constructed with external cooling ribs and fans. And the motors are equipped with solid, longlife stators and rigid rotor construction. The patented rotor construction provides for low vibration levels. ABB's large synchronous motors (1 to 50 MW or 1,340 to 70,000 hp up to 900 rpm) are used in the mining industry for crushing, grinding hoisting and conveying systems. These motors are designed to customer's specifications, including existing foundations. They can be equipped with fixed or adjustable speed control.

Jan 1, 1998

By D. G. Klaren

Self-cleaning fluidized bed heat exchangers are conquering the world for reason that they are able to solve any severe fouling problem in indirect heat transfer due to the circulation of cleaning particles through the tubes of vertical shell and tube exchangers. In most cases, these particles consist of chopped metal wire. Moreover, self-cleaning fluidized bed heat exchangers perform with excellent heat transfer at very low liquid velocities, which enables completely new designs of conventional shell and tube configurations. This article explains the principle and application of this self-cleaning heat exchange technology and also pays attention to an actual case of a revamp of the severely fouling exchangers of a conventional multi-effect evaporator into a self-cleaning configuration. Possibilities for the revamp of conventional exchangers suffering from massive and very hard scale deposits are found in a variety of metallurgical processes, such as: The refining of nickel, the production of alumina from bauxite and many others.

Jan 1, 2003

By Otis M. Clarke

Observations of the land surface show that subsidence over active and abandoned underground mines is controlled to some extent by the stratigraphic and structural geology of the mines in addition to the methods of mining and the thickness of the seam mined. Exposures in highwalls of surface mines that intersect abandoned underground mines in the Warrior coal basin of Alabama illustrate this, showing sandstone beds that act as beams bridging openings and interbedded shale beds crumbling. Stratigraphic changes observed in the district are extremely variable and calculations regarding subsidence used for one area will not apply to another area if there is a major change in rock types Rocks exposed in road cuts and open pit mines demonstrate a marked difference in weathering characteristics. Some rocks, such as shale, wea- ther very rapidly, by crumbling and becoming plastic, whereas other rocks, such as sandstone, resist weathering. The continuing rock weathering after mining in openings produced by the mining activity and in fractures caused by roof movement, apparently, is a major cause of the surface sub- sidence that may occur years after the mines are abandoned.

Jan 1, 1986

By J. Fuller, L. Marsden

Windborne dust from alkaline salt flats and mining-related tailings ponds is especially prone to threaten applicable ambient air quality standards. Sodium carbonate crystals, typically present, weather to an exceedingly fine, non-cohesive dust, causing air quality problems for miles downwind. Recently developed specialized polymers react with alkaline dust to form sturdy, wind-resistant crusts with good longevity. An on-going demonstration project at a major trona facility has developed techniques for cost-effective application of these polymers over large areas of soft tailings or sediments in a wide variety of situations. Recently treated areas on the order of 80 acres show effective suppression of dust.

Jan 1, 2004

By Michael Robert Hodson

I. Introduction The free market cash price of aluminium in the third quarter of 1985 is approximately $1000/tonne, well below the short as well as the long run marginal costs of production. The current disparity between marginal costs and price, as well as the pattern of prices since their high level in 1980, has led many economists to question whether prices are governed by the 'fundamentals'. Prices, some would argue, are the result of speculation; and speculation is irrational, little influenced by the fundamentals of the industry. The object of this paper is first to examine the relation between the fundamentals and price. A number of simple models are formulated and some empirical evidence is given to show that prices are not very different from costs. There are good reasons why costs and prices have fallen since 1980. Second, the connection is drawn between the fundamentals and speculation. To do this the concept of 'rational expectations' is defined and applied to a model of the aluminium industry. Then speculation is introduced into the model and the characteristics of the solution are examined. The object is to discover the new factors that determine prices and the basic change in the nature of the solution that is caused by speculation. 2. Prices and the Simple Supply-Demand Model Consider a simple model of the aluminium industry. Demand, D, is determined by economic activity, A, given exogenously, and inversely by the price, P. Supply, Q, is determined by the inverse of the rnarginal cost curve, and so varies inversely with exogenous factor costs, C, and directly with price. Price is determined by the equality of supply and demand. Given the equilibrium level of demand, price in this model is equal to the rnarginal cost of producing the required level of demand, P = MC (Dl. Algebraically, [ ] How well does this simple model explain the change in prices during the last five years? Table I shows the LME cash price and the estimated marginal cost of producing consumption during the second quarters of 1980 through 1985. The figures in the table show that price and the marginal cost of supplying demand both fell between 1980 and 1982, rose in 1983 and by 1985 had fallen again. Only in 1984 is the direction of change different. And during the 1980 to 1985 period, marginal costs fell by approximately $560/tonne while the LME cash price fell by $678/tonne. There is a correspondence between the fundamentals of cost and price over most of the individual years and the period as a whole.

Jan 1, 1986

By Felicia F. Peng

Flotation process is particle hydrophobic surface-based separation technique. To improve the essential flotation steps of collision and attachment, and reduce detachment probabilities between air bubbles and hydrophobic particles, a selectively designed cavitaion venture-tube can be used to generate very high numbers of pico-nano bubbles to flotation column. Fully embraced by those high numbers of tiny bubbles, hydrophobic particles are readily attracting those tiny bubbles to their surfaces. The results of column flotation of Pittsburgh No.8 seam coal are obtained in a 50 cm ID and 162cm height flotation column equipped with static-mixer and cavitation-venture tube, using kerosene as collector and MIBC as frother. Design of experiment procedure combined with statistical two-stepwise analysis method are applied and attempted to made the optimizing the grade and recovery. The effect of independent variables on response has been explained. Combustible material recovery of 85-90% at clean coal product of 10-11 % ash are obtained from feed of 29.6% ash, with reduced amount of frother and collector than that used in conventional column flotation. The column flotation process utilizing the pico-nanobubbles can also be extended to the lower limit and upper limit of particle size ranges for better recovery minus 75 µm and 300-600 µm, respectively.

Jan 1, 2013

By w. Chruscielewski, T. Domanski

INTRODUCTION Concentration of radon 222Rn and its decay products occuring in the Polish mines of metal-ores call for the necessity of systematic radiation control /Do8la/ both of the working environment and of the miners' personal exposure. The attempts at introducing a system of radiological protection in mines, similar to the ones existing in X-ray or isotope laboratories, took several years and consisted of development of the methods for control of concentration of radon and its progeny in the air, as well as the methods for measuring individual exposure. It was accepted that the assessment of both transient concentration in the air and of personal exposure are basic elements of the control system, which should be implemented independently of each other. Concentration measurement serves to detect and to determine those areas in mines where there is intensive radon emanation, and where current control of the effectiveness of technology introduced to deacrease the concentrations is necessary; personal dosimetry results in the assessment of the actual exposure of miners to radiation. PRINCIPLES OF THE SYSTEM The assessment of working environment is based on concentration measurements of the potential radiation energy of radon alpha decay products. Decentralized assessment is carried out by the special dosimetric service operating in each mine. Dosimetrists are equipped with portable radiometers, type RGR-11, made by the institute of Nuclear Research, Warsaw. The radiometer is presented in Fig. 1. Measurement of filter activity is performed automatically according to Markov's method /Ma62/ or any other method. Simultaneously to potential energy measurement the dosimetrists are measuring the dust concentration in the air and ventilation rate. Ventilation service looks for correlation between those indices and the concentration of radon daughters in the air. Derived Air Concentration /DAC/ for concentration assessment was accepted to be 6.25 10-6 Jm-3 /0.3 WL/ according to ICRP recommendation /Publication No. 24/ /ICRP77/. If environmental measurements reveal potential energy concentration exceeding the value of 0.3 DAC at working places, the miners employed there are subject to individual control of personal exposure. Individual exposure measurement is carried out centrally by the Institute of Occupational Medicine in [Lodz] for all metal-ore mines. Miners who are to be included in the control scheme are referred by a mine management to the Institute where they are registered and assigned a dosimeter. A passive dosimeter with

Jan 1, 1981