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By H. Lind

Mining in Estonian oil shale deposit mainly takes place in the Ordovician, Keila-Kukruse aquifer. The aquifer is affected by mining and is fully dried out around the working mine areas (Perens and Savitski, 2008). The groundwater level is decreased down to 30 m, to the mine floor elevation using about 30 pumping stations (Lind, 2005). The pumping rate is very high - depending on the season, ranging from 10 up to 40 m3 per ton of produced oil shale (Reinsalu et al., 2006). The Estonian oil Shale Company mined 15.5 million tons of oil shale in 2007 (Source: Estonian Oil Shale Company). In order to predict the effects, and avoid the social and environmental impacts, there is a need to continuously monitor the situation and run software simulations aiming at decreasing the pumping rate. This becomes even more important since the environmental taxes on usage of groundwater resources increase every year. Therefore, it is necessary to monitor groundwater level and quality, and develop a groundwater model for the overview of the situation during mine operations and also for a number of years after mine closure.

Jan 1, 2008

By Herman Gill, Dani Delaloye, Madelyn Rubin

The Foothill Tunnel is a remote 16-mile-long untreated drinking water tunnel in the San Francisco Public Utilities Commission’s (SFPUC) Hetch Hetchy Water and Power (HHWP) system. The 14-foot horseshoe shaped tunnel, constructed in the 1920s, is lined intermittently with concrete over approximately 53% of its length, with the balance being unlined rock. After detailed planning, in January of 2020 Mott MacDonald and HHWP staff completed a visual inspection and documented the condition of the tunnel with electronic data collection, photographs, and video with audio recording. The result was a comprehensive condition assessment that identified key areas of the tunnel to monitor.

Jun 13, 2021

By A. J. S. Spearing, B. Forbes, T. Kostecki, A. Hyett

Improving upon the past understanding of the interaction between installed rock bolts, the immediate roof and sidewalls is vital for the implementation of sound support system design, as this has a direct impact on rock-related safety. This is the primary goal in rock-bolt-related research. The earliest research in this field concentrated on limited laboratory and in situ measurements accompanied by theoretical analyses, based on the Kirsch equations. This represented the initial insight into understanding relative ground movements and their impact on primary support. However, these studies were far from complete. More recently, major technological advances in computing power within the mining industry has changed the scope from theoretical analysis to computer simulation. Even with these advancements our understanding of rock bolts in situ and in the laboratory has not progressed, particularly concerning bending and shear. To measure the behavior of rock bolts, the widely accepted practice is to populate the bolts with an array of strain gauges. Historically, resistive foil strain gauges or long displacement sensors have been used. Additionally, all instrumented rock bolts have used only two diametrically opposed slots. Rock bolts instrumented with these methods have significant shortcomings, one of which is the inability to capture shear and bending. The shearing and bending of rock bolts are particularly common in tabular soft rock mining, such as coal mining. This paper discusses the use of three slotted rock bolts, cut diametrically 120º apart, and two new optical fiber technologies populated along the entire rock-bolt length.

Jan 1, 2015

By Cheryl M. McInnes, Graham J. Sparrow, James T. Woodcock

Three composites, assaying about 3 g/t Au and 0.75% Cu, were investigated. Each contained oxide copper minerals, iron oxides, and silicates. One composite also contained copper and iron sulphides. Maximum gold extractions by thiourea leaching were obtained after copper removal by acid pre¬leaching at pH 1.5 and redox potentials of 400 mV (Pt versus SCE). Best thiourea leaching conditions were pH 1.5, redox potentials over 200 mV, and 0.4% thiourea. This gave 90% gold extraction in 2 h with thiourea consumptions of 25 kg/t. Lower potentials gave poorer extractions. Ferrous iron additions before leaching halved thiourea consumptions. Longer leach times and the presence of sulphide minerals sometimes resulted in reprecipitation of gold.

Jan 1, 1989

By Robert M. Stevens

INTRODUCTION Truck haulage of muck in underground mining operations has been in use around the world for many years. From the late 1.950s into the early 1970s, haulage by means of load-haul-dump (LHD) units challenged haulage by means of trucks, and, to a large degree, LHD units dominated the trackless concept of moving mate¬rial underground. However, beginning in 1975, the emphasis began to shift back to the use of trucks, with LHD units assuming the secondary role of loading the trucks. Over the years, several manufacturers have been offering trucks with capacities ranging from 4.5 to 45.4 t (5 to 50 st) and with features that specifically address the constraints of underground operation. TRUCK TYPES Three different types of trucks are available for use underground, namely the tip dumpers, telescoping dumpers, and push-plate dumpers. The following para¬graphs describe each of these three types. Tip Dumpers Tip dumpers are designed to lift the truck box, using gravity to dump the load out the rear of the box. The primary application of these trucks is in the haulage of muck to the surface. However, these trucks also may be utilized underground, if a chamber is provided to accommodate the raised truck box at the dumping point. Fig. 1 illustrates a four-wheel drive truck with a 10.0-t (11-st) capacity; this truck is only 1.9 m (6.25 ft) wide and is designed specifically to follow narrow and winding vein courses. Fig. 2 illustrates a two-wheel drive tip dumper with a 24.5-t (27-st) capacity; this truck operates on 12% grades with firm dry surfaces and in modes both loaded-up and loaded¬down. Telescoping Dumpers Telescoping dumpers specifically address the constraints imposed by low back heights, and they represent an optimization of compressed envelope size with maximum payload capacity. Figs. 3 and 4 illus¬trate a typical telescoping dumper with a capacity of 18.1 t (20 st). Fig. 3 shows the box in position for carrying the load, and Fig. 4 shows the same truck with the box in the full-dumping position. Fig. 5 illustrates the loading and dumping cycles. Fig. 6 illustrates an approximation of how an LHD unit with an eject-o-dump (EOD) bucket would be used to load over the rear of this type of truck. Fig. 6 shows a low-profile telescoping truck in the first stage of loading, with a 6.8-t (7.5-st) LHD unit equipped with an EOD bucket. A loader with a smaller capacity and a narrower bucket would allow the bucket to fit inside the truck box and would achieve an even lower loading height than that illustrated. Gen erally, an LHD unit equipped with an EOD bucket and teamed with a telescoping dump truck can be used with a lower back height than could any other front-end loader and truck team. Push-Plate Dumpers Push-plate dumpers are similar to telescoping Bump¬ers, except that they do not have the two-stage box. Instead, push-plate dumpers utilize a single push plate to discharge the load out the rear of the box. Gen erally, these units are limited to payload capacities of about 9 t (10 st). Fig. 7 illustrates a typical push-plate dumper.

Jan 1, 1982

By Joel Lööw, Johan Larsson, Stig Vinberg, Malin Mattson Molnar, Mats Jakobsson, Jan Johansson

The mining industry is undergoing rapid transformation, driven by technological advancements, sustainability concerns and demographic shifts. This transformation will put more younger people in management positions. This study provides valuable insights into the leadership behaviors of younger and older managers within a large Swedish mining company, highlighting the importance of managerial experience and targeted training programs to foster effective leadership, particularly in the context of change management. The findings emphasize the need to create work environments that support managers to develop their leadership, contributing to improved employee well-being, operational efficiency, and adaptation to the changing demands of the modern mining sector.

May 1, 2025

By N. S. Tanious

This paper summarizes results from an investigation into possibly the largest coal pillar failure in the USA. The newly opened coal mine worked an 3.35 m (11 ft) seam under overburden depth that ranged from 91 to 671m (300 to 2200 ft) . The mine main entries, and the enclosed pillars, experienced a massive slow squeeze. The squeeze could not be controlled and the mains were lost. A new set of mains were driven. Entry convergence (closure) measurements were carried out behind the advancing face to monitor stability. Pillar stresses were also measured under four different depths of overburden: 229.433, 472.579 m (750,1420,1550, and 1900 ft). The strength of pillars in the new mains was calculated from the loads that triggered the failure in the old mains, using three pillar strength formulas. The stress measurements showed that the new pillars supported more load than their predicted strength, indicating that current strength formulas are inadequate under deep conditions.

Jan 1, 1992

By Walter C. Labys, William A. Vogely, David O. Wood

INTRODUCTION The past decade has witnessed a literal explosion in formal modeling of energy systems and markets. This rapid development was stimulated primarily by policy issues arising from the energy price shocks of 1973- 1974 and 1979- 1980. The suddenness of this interest is illustrated by comparing the current and earlier editions of Mineral Economics. The third edition, published in 1976, includes an addendum to the section of projection and forecasting methods because, Since the foregoing chapter was written, major events in petroleum have caused an explosion in formal modeling efforts in the energy field.a In contrast, this fourth edition includes the present chapter on energy modeling, and a separate chapter on nonfuel minerals modeling. The considerable interest in formal energy models is based on the complexity of the system, in particular the interaction between technical and engineering data and designs, and economic behavior of energy producers and users. Energy is a vital component in the economic and social well-being of nations, and must increasingly be explicitly considered in developing economic growth and welfare policies. Energy models can contribute to policy development and analysis, both by improved understanding of the energy system, and of the interaction between energy markets and the economy, and as an explicit means of analyzing and comparing the implications of alternative policy actions. At their best, formal models can clarify and illuminate policy options. In this chapter we will survey the objectives, methods, and potential contributions and limitations of energy system modeling. Section 2 considers the objectives, scope, and approaches to energy system and market modeling. Methodological approaches are then discussed more formally in section 3. Our approach is to intro- duce each model type and method via relatively simple generic models, illustrating their use by a selective review of the applications literature. Section 4 shifts the focus from modeling methods to procedures for model evaluation and improving model credibility especially in policy research and analysis. We conclude with some brief remarks on directions and opportunities for future modeling research. ENERGY MODELS: OBJECTIVES, SCOPE AND APPROACHES The concept of a model usually evokes an image of a complex, computerized system of mathematical or econometric equations providing detailed information concerning the operation of the process being modeled. In fact. models may be simple or complex, formal or mental, depending upon the purposes for which the model is intended. Simple judgmental models may be most appropriate when monitoring the overall performance of a process. When more detailed information is required and/or when the model

Jan 1, 1985

By R. R. Oder

Reported are weight, particle size, gross chemistry and magnetism measurements for lithic, mineral and fused soil components separated from five lunar soils using dry, open-gradient, magnetic separation. Pure diamagnetic anorthite, a feedstock for the electrochemical separation of oxygen and metals, has been separated from anorthistic highland soils. In addition, paramagnetic ilmenite has been separated from high-titanium, basaltic mare soils. Ilmenite, a feedstock for oxygen preparation by hydrogen reduction, may also serve as a source of He3 for use in fusion power generation. Agglutinates (vesicular, glassy components containing metallic iron) have been separated from all of the soils. Iron and refractories can be used for space construction. Metallic iron is easily detected in lunar soils by magnetic susceptibility measurements. Based on the exploratory laboratory results, conceptualizations of innovative magnets for processing lunar soils are presented.

Jan 1, 1993

By R. Hogg, L. G. Austin, R. C. Klimpel

Slurry densities and holdup were measured for open circuit grinding tests in a laboratory overflow ball mill of 0.3 m diam by 0.6 m long, by emptying and drying after stoppage of the mill. Contrary to some other results in the literature, there was negligible variation of slurry level in the mill as a function of flow rate over a range of increase of flow rate of about 5 to I. However there was a gradual increase of solid holdup at higher flow rates because the slurry density in the mill increased. Equations are given for holdup and slurry density in the mill as a function of over flow diam, ball load, and feed slurry density. The average level of slurry necessary to give over flow was found to be much higher than that necessary to fill the mill to the overflow level at rest. The total level of balls and slurry was only increased slightly by ball loads higher than the overflow level. The overflow diam appeared to be the major controlling factor in determining the mill holdup.

Jan 1, 1990

By J. A. Herbst, S. L. Blust

Optimization of blasting, crushing, and grinding operations is filled with challenges. One of the more difficult tasks is accurately sampling and determining the size distributions of blasted and crushed materials at a reasonable cost. The task is difficult because of the large size of fragments and the tonnage involved. However, the size distribution measurements are necessary for models that predict the performance of mine-through-mill operations. This paper is concerned with the use of video sampling for this task at National Steel Pellet Company's operation in Keewatin, Minnesota Data gathering, data analysis, model building, and mine-to-mill simulation are all described.

Jan 1, 2000

By William S. Pintz, William A. Vogely, Charles J. Johnson

This chapter on the role of minerals in developing economies is oriented toward economic policy issues. The discussion and analysis cut across the technical, economic, legal, and policy fields. The goal of this chapter is to pro- vide relevant background information important to individuals involved with the minerals sector in developing countries. Where possible, trends are shown to provide a basis for understanding the evolving role of minerals in developing economies. This chapter is divided into the following five sections: (1) characteristics of developing countries (which presents selected statistical comparisons); (2) government objectives in developing countries; (3) government policy formulation in developing countries; (4) determinants of future trends, and (5) a summary of the chapter's major points combined with the authors' view. CHARACTERISTICS OF DEVELOPING COUNTRIES There are 155 nations in the world categorized as "developing countries." In total these nations represent about one third of the value of the world's mineral production, three quarters of the world's population, and over half of the world's land surface area. The group of so-called developing countries is quite diverse and there are exceptions to almost any general observation about the group as a whole. Most definitions of the term "developing country" are based on levels of per capita income. However, if per capita income is the sole criterion used in categorization, then several oil-exporting countries would jump from the category of developing country to the category of developed country.a Obviously, this results in a poor fit with respect to other measures. In general, the majority of developing countries can be characterized by relatively low per capita income, high population growth rates, high levels of unemployment, low levels of education, short average life ex- pectancies, income distribution skewed toward the highest 20% of the population, and a large share of exports represented by primary commodities. b For the purposes of this chapter a slightly modified version of the widely used World Bank system of classification (shown in Table 1.2.1) is used. As summarized in Table 1.2.1, developing countries are divided into three main groups based on estimated gross national product (GNP) per capita. It should be noted that the high- income, oil-exporting countries have characteristics of both developing and industrialized countries; however they are included for most statistical comparisons within the group of developing countries. Of the 155 developing countries in the world, approximately half produce minerals other than common building materials, and only 32 account for more than five percent of world pro-

Jan 1, 1985

By A. L. Stomberg

Federal and State surface coal mining regulations require special handling of prime soil materials which result in additional costs, and no actual benefit when prime and non-prime soils are similar. The Coteau Properties Company proposes to mix both prime and non-prime topsoil and subsoils at the Freedom Mine in Mercer County, North Dakota, based on an analysis of soil physical and chemical characteristics which show these materials to be comparable.

Jan 1, 1985

"A commercially available Through-the-Earth (TTE) communications system was evaluated at an active underground longwall mine in West Virginia. This TTE system uses electric field (E-field) sensing to send text based communications using two separate antenna arrays connected in parallel. Each antenna array is composed of interconnected, grounded metallic rods or other such structures. Two-way communication between subsurface locations was investigated in this study using various antenna configurations. This field study was conducted as a part of a larger multi-site evaluation of available TTE systems in an effort to determine their operational sensitivity. INTRODUCTION Wireless, Through-the-Earth (TTE) communication technology is designed to achieve point to point communication through solid strata using very low frequency (VLF) and ultra-low frequency (ULF) electromagnetic waves. This ability allows TTE communication to function without the need for intermediary communications infrastructure, such as repeaters. As a result, such communication systems have the potential to provide reliable, robust communications between surface and underground personnel. Exploration into the use of TTE technology for this purpose dates back to the 1920s (Jakosky and Zellers 1924; Pittman, Church and McLendon 1985), but U.S. permissibility requirements slowed the development of TTE equipment for widespread implementation (Durkin 1980; Pittman, Church and McLendon 1985). One of the primary challenges in producing wireless TTE communications is the counteraction of signal attenuation when propagating through solid strata (Barkand, Damiano and Shumaker 2006; Wadley 1949). The long wavelengths of TTE transmissions make them well-suited for reducing the rate of attenuation. However, even when operating within the VLF to ULF range, the performance of TTE systems is still affected by geologic and anthropogenic factors (Geyer 1973; Geyer and Keller 1976; Geyer, Keller and Ohya 1974; Jakosky and Zellers 1924; Large, Ball and Farstad 1973). Although commercially developed TTE systems have demonstrated the ability to communicate through a variety of conditions, their range and performance have been highly varied (Barkand, Damiano and Shumaker 2006; Geyer and Keller 1976; Geyer, Keller and Ohya 1974; Ilsley, Freeman and Zellers 1928; Jakosky and Zellers 1924; Yenchek et al. 2012)."

Jan 1, 2016

A portable electronic instrument was developed which will measure change of longitudinal wave velocity with change of uniaxial stress in rock columns. The instrument is a solid-state device powered by nickel-cadmium batteries. It uses a probe of two piezo-electric crystals spaced inches apart to send and receive a pulse through a stressed rock. A one-inch cathode ray oscilloscope visually displays the longitudinal wave. A reference chart is used to find the stress. Laboratory results have indicated that the average stress on a sandstone column can be found to within 35 psi. The feasibility of using this instrument to determine stresses in mine pillars is to be studied. The instrument may be used to investigate physical properties of rock.

Jan 1, 1970

By D. W. Carson, R. J. Trembley

Thoron daughter WL&apos;s measured by alpha-spectroscopy and the Kusnetz method are about one-half those of radon daughter WL&apos;s in a uranium mine in Canada.1 A diffusion model can account for the relative concentrations.l Since the Kusnetz technique is most widely used for measuring radon daughter WL&apos;s in uranium mines, a general procedure is derived to extend this method to measurement of WL&apos;s of radon and thoron daughters in air containing their mixtures. Coté P. and Townsend M.G., 1981. A procedure is also suggested for counting radon and thoron daughters by 3-channel [a]-spectroscopy. Errors in WL(Rn) are calculated for standard radon daughter counting procedures when a-decay of both thoron and radon daughters is attributed to radon daughters alone. Providing overall counting times are short, [<]30 min, these errors are generally small. The precision of ß -counting methods is also investigated. A portable 3-channel alpha spectrometer for measurement of radon and thoron daughters in uranium mines or homes is described, Carson D.W., 1979. The computer programs for analyzing the data to give, depending on the mode employed, some or all of the concentrations RaA, RaB, RaC, ThB, ThC and WL of radon and thoron daughters by alpha spectrometric, modified Kusnetz, Rolle and Tsivolglov methods are presented.(l) A commercial apparatus, based on the above prototype, incorporating a microprocessor and built under contract to EMR is now available.(2) A number of personal radiation dosimeters for miners are now being tested in mines. One of these is the CEA dosimeter which uses the track-etch film method, Duport P., Chapuis A.M. and Pradel J., 1979. An apparatus for rapid reading of track-etch films by the spark technique has been described previously, Cross W.G. and Thomasino L., 1970 and Huang V.F., 1975. We have developed such an apparatus for rapid semi-automatic reading of films exposed to radiation from mixtures of radon and thoron daughters in CEA dosimeters. The films used, Kodak LR 115 Type II Strippable, may be stripped rapidly and easily, for counting after irradiation and developing, by use of a special punch and suction technique. The method promises to provide an inexpensive and rapid technique for reading large quantities of personal dosimeter films. However, the present CEA dosimeter has faults in design, leading to a contamination problem. Those films that show contamination cannot be read by automatic means. A commercial apparatus based on the above prototype spark counter and built under contract to EMR is now available.3 1. These computer programs are available on request. 2. Pylon Instruments, Ottawa 3. Bondar Clegg, Co. Ltd., Ottawa. REFERENCES Carson, D.W., 1979, "Canalph-3, a Portable Three-Channel Alpha-Spectrometer for Measuring the Daughter Products of Radon and Thoron", CANMET Division Report MRP/MSL 79-108 (TR). Coté, P. and Townsend, M.G., 1981, "Mixtures of Radon and Thoron Daughters in Underground Atmospheres", Health Physics, Vol. 40, pp 5-16. Cross, W.G. and Thomasino, L., 1970, "Rapid Reading Technique for Nuclear Particles Damage Tracks in Thin Foils", Radiation Effects, Vol. 15, pp 85-89. Duport, P., Chapuis, A.M. and Pradel, J., 1979, "Appareil Individuel pour lu Dosimetrie des Descendants du Radon", Advances in Radiation Protection Monitoring, IAEA Vienna, pp 435-443. Huang, Y.F., 1975, "Determination of Uranium in Minerals using Fission Tracks", M. Sc. Thesis, University of Toronto, 48 pp.

Jan 1, 1981

By G. E. Burrer, D. Malhotra, T. E. Irwin, S. Johnson

Climax byproduct-plant tailing assayed 0.019% WO3. Pilot-plant and laboratory tests were performed to investigate the possibility of recovering additional tungsten values from the byproduct-plant tailing. The methodology used in the study and the results of this investigation are discussed.

Jan 1, 1987

By Shiro Ishii

When construction sites are in a densely- populated area or near roads, railroad or river, restrictions upon the ways of handling and using explosives such as dynamite and large demolition equipment are being increasingly stringent, in consideration of environmental pollution such as noise, vibration, dust, flyrocks etc., and safety precaution. In view of this, the development of safe and pollution-free technology for demolishing rocks at mines and reinforced concrete structure at building sites is strongly required. To meet such requirements, the demolition by means of expantion of mineral substances has been considered long before. Recently with the demolition technique using non-explosive demolition agent developed by ONODA CEMENT CO., LTD., holes are drilled into substances to be demolished, such as rocks and concrete before-hand. Then, slurry of such agent mixed with an appropriate quantity of water is poured into the holes. It hardens and expands with the passage of time, and the expansive stress reaches more than 3m/m2 in 10 to 24 hours. This expansive stress causes the material to crack. In this article, descriptions of the non- explosive demolition agent, BRISTAR manufactured by ONODA CEMENT CO., LTD., TOKYO, JAPAN, are given briefly with regard to its physical and chemical properties and its method of use; and the way it is used at an actual construction site is reported.

Jan 1, 1982

By Charles R. Garrett

The American Borate Company, a wholly owned subsidiary of the Owens Corning Fiberglas Company under a management contract to the Hanna Mining Company, owns and operates an underground borate mine in Death Valley, California. The mine, named the Billie Mine, is located 24 km (15 miles) southeast of Furnace Creek along Highway 190. The ore body is under Death Valley National Monument with the major portion of the surface facilities located just outside the monument boundary. (See Figure 1.) The Billie Mine produces approximately 227 000 metric tons of crude ore per year. About 65% of finished product is supplied to Owens-Corning, the remainder is sold to other fiberglass producers. Geology The borate minerals in the Billie ore body were deposited in the lower main member of the Furnace Creek Formation, which is Pliocene in age. The ore body is thought to have formed from volcanic springs in or near a small lake basin. The deposit is essentially a limestone breccia that is permeated with borate minerals and surrounded with limey lake bed mudstones and shales. The ore body is mineralized with two main borate ores, colemanite and probertite. A third borate ore, ulexite, mainly occurs in the upper part of the ore body. The original mineral of deposition is thought to have been ulexite. Ulexite is a sodium-calcium borate hydrated with eight molecular waters. Due to heat and pressure from burial by later sediments, the ulexite had water forced out of its structure and recrystallized as probertite. Probertite is another sodium-calcium borate, with five molecular waters. Colemanite formed when surface water seeped into the prober-

Jan 1, 1985

By T. M. Yegulalp

Geometric programming is a mathematical optimization technique, first formulated by Zener [1], for dealing with certain types of functions which typically arise in engineering design problems. The theory provides algorithms for finding the optimal solution, existence theorems by which one can show that a particular design is possible or not; and characterization theorems that especially make possible to obtain the relationships among the optimal design parameters at optimum. It has been demonstrated [2] that this technique can be applied to several design problems in chemical, electrical and mechanical engineering. Design problems in mining, metallurgical and mineral engineering have many aspects similar to that of other engineering problems. Thus it is only natural to consider geometric programming as a potential tool for solving certain optimization problems in mineral industries.

Jan 1, 1974