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Since the Rio Declaration on Environment and Development in 1992 in Rio de Janeiro and the publication of the agenda 21, the concept of Sustainable Development has become one of the major issues for governmental politics, societal developments and entrepreneurial policies. Current projects that deal with Sustainable Development in the mineral raw materials sector mainly focus on large-scale mining operations - especially for open pit mining - or on artisanal small scale mining. Artisanal small scale mining is in this connexion characterised as non-mechanized and mostly illegal mining activities. The number of workers is mostly far below 20. However, until now there exist no assessments or analyses with respect to the actual or potential contribution of industrial small scale mining to sustainable development. Industrial small scale mining refers to high technology or highly mechanized/automated extraction of small, high-grade deposits that due to their small size ? in combination with geological, depth and other constraints ? are not economically exploitable with large-scale mining operations. The Institute of Mining Engineering I and the Institute for Processing of Mineral Raw Materials at the RWTH Aachen University in Germany is currently conducting a research project financed by the German Research Foundation in order to investigate this issue. In the course of this project the sustainability of industrial small scale mining will be assessed. Therefore sustainability indicators, an assessment system and recommendations as well as options for actions and policies will be developed, in order to evaluate current industrial small scale mining activities as well as the potential for future developments in industrial small scale mining, both from a technological as well as from the point of view of sustainability, considering economical, social and environmental chances and risks.

Jan 1, 2007

By W. M. Luff

Introduction The Brunswick No. 12 mine is located about 27 km (17 miles) southwest of Bathurst, New Brunswick. The deposit is a stratiform massive sulfide deposit occurring in a series of sedimentary and volcanic rocks of the Tetagouche Group. These rocks are generally considered to be Ordovician in age. Ore reserves at Brunswick No. 12 are 104 Mt (115 million st) grading 3.72% lead (Pb), 9.01% zinc (Zn), 0.32% copper (Cu), and 97.9 g/t (2.8 oz per st) silver (Ag). Production in 1984 was 3.5 Mt (4 million st) at 3.57% Pb, 8.91% Zn, 0.32% Cu, and 100 g/t (2.9 oz per st) Ag. Total payable silver production that year was 211 t (6.8 million oz). This made Brunswick one of the largest silver producers in Canada. Bathurst-Newcastle area and Brunswick Mining Interest in the Bathurst area was aroused in 1897 when W. Hussey discovered an iron formation at Austin Brook, just south of Brunswick No. 6 deposit. This area, and the current No. 6 area, was explored from 1897 to 1907. Iron ore was mined at Austin Brook from 1907 to 1913 and from 1942 to 1943. Any occurrence of sulfides was overlooked until 1952. In 1952, M. J. Boylen Enterprises investigated the small sulfide body associated with the Austin Brook iron formation. Other electromagnetic anomalies associated with the iron formation were investigated. The No. 6 deposit was found late in 1952, when hole B12 intersected 97.5 m (320 ft) of massive sulfides. The No. 12 deposit, 10 km (6 miles) to the north, was found in 1953. More than 30 massive sulfide deposits have since been identified in the Bathrust area. In the 1950s, St. Joe Lead Co. did extensive test work on the No. 6 and No. 12 deposits, including shafts at No. 12, lateral development at No. 12, and testing at both deposits.

Jan 10, 1986

By Luther J. Russell

Mineral development in South Dakota is aggressively encouraged by both state statute and county ordinances. Yet, an increasingly conservative philosophy is taking hold, resulting in expanded regulatory controls and concomitant increases in direct and indirect costs to permit and operate a mining operation. This paper examines the hidden costs associated with protracted permitting timeframes, land buy-outs, attorney's fees, etc., associated with the increasing emphasis for stiff controls on mineral development in South Dakota.

Jan 1, 1998

By Rashi Tiwari, George Danko, Jeremy Knowles

A control technique is described for enhancing the efficiency of materials handling and other mining operations. The concept involves human-operator and robotics control interactions to assist in mining operations. Many mining tasks require a human operator to coordinate the motion of several machine links by simultaneously manipulating multiple joysticks or other control devices. The new control architecture allows for automatic coordination of multiple machine joints. The machine movement may follow a computer-optimized, learned coordination pattern, while the operator still retains the master control of the overall trajectory and velocity parameters. Examples are described for a surface mining front shovel.

Jan 1, 2005

By Michael F. Jeglic

Dust control methods are practiced throughout the mining industry in order to protect the health and safety of its workers, the integrity of the environment, and to guard against the loss of valuable product. The use of water is often the best and most economical method of controlling dust. Increasingly, chemical agents are being chosen over more traditional mechanical means of controlling dust. Some chemicals are used alone, and many are used to enhance the dust controlling properties of water. This paper describes the various types of chemicals available and their applicability to specific problems encountered by industry.

Jan 1, 1986

By N. S. Margaris

The vegetation of Mediterranean ecosystems is distinguished by its resistance to adverse environmental conditions, and that is the reason for examining the possibility of growing species of this flora in waste disposal sites (WDSs). The survival and growth of vegetation established at a waste disposal site is dependent to a large extent on the qualitative and quantitative characteristics of the material used in the final soil cover. In the Ano Liossia WDS, where extensive remediation work is under way, three areas were examined, which met certain criteria in relation to the age of the underlying waste and the existence of impermeable material in the final soil cover. Laboratory analyses have determined soil parameters and nutrient and heavy metal content. Alongside this, at all three sites a network has been installed to monitor the qualitative characteristics of the gaseous phase of the soil cover material. The results showed the existence of a soil material containing few nutrients and the prevalence of oxygen-poor conditions, accompanied by large concentrations of CH4, CO2 and H2S, at depths of up to about one meter.

Jan 1, 2002

By Sheldon P. Wimpfen

Forecasting, an ancient art, is con-ducted by everyone in varying degrees. It is a vital aspect of mineral production and conditions must be predicted over a long time frame in all aspects of the industry from exploration to plant construction. Although many government agencies as well as private industry make forecasts, there are insufficent "make good" analyses performed. The performance of more such studies could sharpen forecasting ability.

Jan 1, 1983

By John D. Abbatt, H. B. Newcombe

The Eldorado Epidemiology Project formally began in late 1978. It consists of a retrospective cohort study, to be followed by and to leave in place the mechanism for a prospective cohort monitoring program. These present and future activities are intended to merge into one another. The current study includes all Eldorado employees past and present for whom records are available. The objectives of the undertaking are - 1) to obtain cause-and-effect, dose-response data with which to evaluate the risks to workers in radon and radon daughter containing atmospheres, and to provide additional quantitative information on which to base possible improvements in working conditions; 2) to identify any dead employees of E.N.L. whose cause of death suggests that a potential compensation claim right exists for their survivors, and to similarly identify living ex-employees of E.N.L. whose work histories and states of health suggest potential compensation claim rights. The nature of the study has been determined by the history of Eldorado, which will be described briefly. Eldorado began (as Eldorado Gold Mines) in the late 1920's, operating relatively unsuccessfully in Manitoba. In 1930-31 the emphasis shifted from gold to uranium, and what became the Port Radium mine was first staked. From the very early 1930's until 1942 the company's purpose was almost entirely devoted to the mining of pitchblende - uranium ore - from the Port Radium site, and the extraction of radium from this ore at the Port Hope refinery in Ontario, a process from which the uranium was a largely stockpiled byproduct. In 1942 the company was requested by the Canadian government to accelerate the production of ore, and of uranium. At the same time, all its stockpile of uranium (then being stored in silos as a "waste" product which might later "come in") was acquired for the Manhattan Project. In 1944 the company shares were bought by the Canadian government and the company itself became Eldorado Mining and Refining (1944) Limited; it has operated as a Crown corporation ever since. The name was changed to Eldorado Nuclear Limited in 1968. The Port Radium mine was closed in 1960, and since 1953 the Beaverlodge uranium mine complex has operated on the northern shores of Lake Athabasca. Radium production was discontinued in 1954 when the radium circuit was taken out of the refinery, and since that time the refinery's products have been various types of refined uranium (uranium dioxide, uranium trioxide and uranium hexafluoride) plus metallic uranium. The refinery, of course, processes the company's own yellowcake but as it is one of only five refineries in the western world, most of its work consists of custom refining for a large variety of customers. In addition to the mining and the refining operations, there have been three other divisions involved, and these are, respectively, Aviation, R. & D., and Exploration, in addition to the financial, corporate, administrative and support activities. MATERIAL AND METHODS The human study population (Abbatt, J.D. et al., 1980) consists of all Eldorado employees who have ever worked for E.N.L. and for whom records are available. The total nominal roll to December 31, 1980 is approximately 21,000 and consists of employees of the Mining, Refining, R. & D., Aviation and Exploration Divisions, as well as a relatively small number of other employees (Head Office, etc.). The basic epidemiologic design, as has been mentioned, is for a retrospective cohort study merging into a prospective cohort study, and depending very heavily upon automated record linkage and file matching. The original design called for an initial assembly of the bulk of the nominal roll, prior to the first of two matches with the National Mortality File. The first of these two matches is now complete and the second is to be separated from it in time by 18 months to two years. The second match will be the definitive match prior to the analysis, the interpretation of the data, and the publication of the results. The period between the two matches was designed to permit completion of the nominal roll, including: - addition of previously missing individuals and groups, elimination of duplicates, and amplification of identifying information, - assembly of work histories and exposure information for each individual, - digestion and application of lessons and modifications resulting from the first match with the National Mortality File at Statistics Canada, - preparation of files for the definitive second match. The analysis of data will be carried out by the National Cancer Institute of Canada Epidemiology Unit based at the University of Toronto. This group, with whom Eldorado Nuclear has a memorandum of understanding, have for a variety of reasons, including their familiarity with record linkage and their expertise, been members of the Project Team since

Jan 1, 1981

By M. H. Al-Dabbagh

In this paper, the authors outline the deficiencies of PERT/CPM as a method for scheduling complex projects such as mine development. In particular, PERT/CPM networks cannot accommodate logical nodes (events) or stochastic branches (activities). The Graphical Evaluation and Review Technique (GERT), developed by Pritsker and. co-workers, is introduced as an alternative to PERT/CPM that overcomes many of the deficiencies of the latter and enables a more realistic analysis of complex projects that are subject to significant uncertainties. A brief overview of GERT network structures and network analysis is given and a PC implementation of the method is described. The technique is illustrated by application to the development of an open-pit gold mine in Saudi Arabia.

Jan 1, 2002

By A. Anttila, S. Persson

The grinding mill is probably the most common unit operation in mineral processing. There is, however, much that can still be done in the way of optimization. This paper discusses the results of a well-controlled pilot-scale test in which the performance of a tumbling mill equipped with a conventional rubber lining and lifter bars was compared to a tumbling mill equipped with a smooth rubber lining of the magnetic type. The results indicate that the smooth lining is about 14% more effective with respect to energy consumption. By optimizing the size of the grinding media, the mill capacity can be increased in many grinding operations. In this specific case, grinding with a -20-mm ball charge required 26% less grinding energy than grinding with a -30-mm ball charge. The energy savings can, in most cases, be converted to an increase in capacity. The wear of the grinding media is difficult to assess over a short test period, but the results suggest that the wear is somewhat less when a smooth lining is used. A determination of the wear of the linings was not included in this study, but it is generally accepted that the use of magnetic linings reduces the lining costs dramatically. Computer simulation using the Millsoft code developed by Mishra et al. confirms and explains the increased effectiveness of comminution when a smooth lining and smaller grinding balls are used.

Jan 1, 2000

By Arthur P. Chase

The Tacubaya subway tunnels form a link in the Sistema de Transporte Colectivo (Mass Transit System) of the Federal District of Mexico. One tunnel 327 m long lies to the north of Tacubaya Station, the other 811 m long, to the south. The tunnels are designed to accommodate two subway trains, one inbound and one outbound, within the inside diameter of 8.5 m. The designers of the tunnel lining and tunnel driving equipment were faced with the problem of driving two subway tunnels 9.0 m outside diameter through water-bearing soil, directly beneath a high speed limited access highway, a main drainage sewer, structures including residences and office buildings, on an alignment curved for 67 per cent of tunnel length, and on grades as high as 7 per cent, within a limited budget, with minimum damage to property and disruption to the community. Planning The following decisions affecting tunnel design and construction were made at an early stage of planning: Shield. To enhance safety, a tunnel shield would be used for tunnel driving. Dewatering. The water-bearing soil could be effectively dewatered; consequently, tunnel driving could be performed in free air. Hand Mining. To minimize investment in equipment, hand mining would be used to excavate and support the face.

Jan 1, 1997

By A. Wahab Khair

There are a number of factors, including mine geometry, local geology, geotechnical properties of overburden materials, surface topography, sequence of overburden strata, and extraction rate, affecting characteristics of surface subsidence imposed by large underground excavation. Among the factors, the first three have the major impact on magnitude and area of influence of final subsidence. Hence, a model has been developed, considering mine geometry and geologic and geotechnical properties of the associated area, to predict maximum possible subsidence and subsidence profile at any cross-section within the subsidence influence zone. Based on extensive field measurements and mechanics of strata behavior, under the action of overburden pressure in the vicinity of the large underground excavation, the vertical plane of influence zone has been divided into five areas: 1) excavated, 2) caved, 3) fractured, 4) highly deformed but continuous, and 5) subsided zones. In the final state of subsidence each area maintains a certain volume expansion/contraction, i.e. a factor which depends on geologic, geotechnical properties of overburden strata and state of stress within the subsidence trough. The cumulative volume expansion and contraction partially compensates for the extracted volume and the difference between the two is reflected as the subsided area in the form of the area within a curve defined by a probability function. The input parameters for the model are mine geometry (i.e. length and width of the panel), depth of cover, and geologic and geotechnical properties of overburden strata (i.e. percentage of hardrock, sandstone and limestone, and soft rock, shale within the overburden strata and Rock Quality Designation). The model calculates angle of draw for the site, expansion factor for each zone utilizing empirical relationships, maximum possible subsidence and plots the subsidence profile curve. The model is developed for a longwall excavation with unique characteristics of prediction of angle of draw and maximum possible subsidence for a given geologic and mining condition at any cross-section within the influence zone of subsidence.

Jan 1, 1986

By P. M. Hawley

Kennecott Corporation, in joint venture with Galactic Resources Ltd., recently began operation of an open pit gold mining and milling facility near Columbia, South Carolina. The deposit consists of two ore bodies (North and South deposits) hosted in deformed and altered meta-volcanics and meta-sediments of the Carolina Slate Belt. This paper describes the rock mechanics and engineering geology investigations conducted for design of interim, ultimate and final reclamation slopes for the South Pit. Emphasis includes the successful use of drill core orientation techniques to confirm complex geologic structure at depth; the development of a three-dimensional rock mass competency model, incorporating surface mapping data, results of bench mapping documentation, field index testing and laboratory testing; and kinematic assessments for design of optimum slopes.

Jan 1, 1991

By F. M. Benavides

The mining complex being analyzed consists of four mines and two processing plants located in an area where there are several existing modes of transportation. Figure 1 shows a map of the general layout of the four proposed mines and the two existing processing plants. The mines are identified by the numerals "I" through "IV" and the plants by the letters "A" and "B". A proposed overland conveyor would collect the product from all four mines and convey it to Processing Plant A. Alternate transportation systems are as follows: Railroad transport from Mines I and II to Plant B; Highway trucking from Mines I and II to Plant A; Off-the-road truck haulage from Mine III to Plant B and from Mine IV to Plant A. River transportation from the mines to the processing plants was not considered in this study under the assumption that the high capital investments for the loading and unloading facilities, in addition to difficult traffic problems, would make this mode of transportation unattractive.

Jan 1, 1980

By P. R. ZETTWOOG

HISTORICAL BACKGROUND A program in France to develop personal [a] dosimeters has been initiated 1974. The patent on which is based the present device was obtained in 1972 * . From 1972 to 1974, the possibilities of applying certain ionograph track detectors to the spectrodosimetry of radon daughters was explored. The first prototype were produced in 1974. It took four years (from 1974 to 1978) to produce an autonomous dosimeter whose components has a sufficient life span, especially for the turbine motor unit. Qualification in the laboratory was obtained in 1977. In 1978 it was obtained in the mine for technology (autonomy of 12 hours and a life span of more than one year) and in 1980 for monitoring. 300 dosimeters have been tested in underground mines all together. Indispensable peripheral equipment were also developed from 1976 to 1980 : calibration devices, equipment to prepare and develop the films, read out systems. The concept of an "Integrated System of Individual Dosimetry" (ISID) based on a personal [a] dosimeter measuring exposure to radon daughters, thoron daughters, ore dust and external irradiation doses was proposed at the end of 1980. Since January 1st 1981, ISID is used on a routine basis in some french mines, situated in remote area, and appears to be very competitive with the ambiant dosimetry. The latest version of the dosimeter is produced in mass series since June 1981 and should equip all french mines in 1982. DESCRIPTION OF THE INSTRUMENTATION DEVELOPMENT OF THE DOSIMETER MEASURING HEAD The measuring head is based on the use of ionographic film to detect a tracks. In fact, the measuring head is a spectrodosimeter which measures separately over the period of exposure: - the potential [a] energy inhaled due to the decay of Po 218, Po 214, and Po 212 ; - the number of Rn 222 atoms inhaled ; - the inhaled total [a] activity of the five long-lived emitters present in the ore dust. The contribution to the total inhalable potential [a] energy of these various radionuclidesin a typical underground mine is studied in Appendix I. The measuring head described in detail in Appendix II, is able to satisfy all the implications made in the ICRP recommendations. Appendix III deals with the use of this measuring head in the cases where the equilibrium factor is lower than 0.1. This situation occur in open-pit mines where account must be taken of the Rn 222 contribution, which is no longer negligible in relation to that of its daughters. CURRENT DOSIMETER PERFORMANCES Table I shows the characteristics of the latest dosimeter. Appendix IV should be consulted concerning qualification of the dosimeter in the laboratory and in mines, technological development which finally produced the [a] dosimeter and its peripheral equipment, and technical presentation of the ISID (Integrated System of Individual Dosimetry) based on the concept of a multirisk personal dosimeter. Data on the installation and operating costs of such a dosimeter, which would seem to be competitive, are also given in this Appendix. ADVANTAGES OF PERSONAL DOSIMETRY AS COMPARED TO AREA MONITORING The results of the first eight months of experiments carried out under real conditions in an underground mine site are given in detail in reference 8. Area monitoring : The monthly exposure per worker to inhaled Rn 222 was determined from the knowledge of time spent in various areas of the mine and for the different mining operations, as well as from numerous and systematic sampling of the Rn 222 concentration in all work places. Personal dosimetry : The exposure to potential energy from radon daughters was measured by an [a] dosimeter developed by the CEA and worn by each of the 160 miners during eight months. In this way 160 x 8 pairs of monthly individual exposure values have been obtained which can be statistically studied. This test was decisive for us because it proved that the [a] dosimeter was technically sound (very few defects over one year for 160 dosimeters) and especially that personal monitoring devices were superior to area monitoring devices. The following conclusions can be drawn 1. The exposure distribution obtained by personal dosimetry is log-normal. This is true for the results on the whole as well as for groups of results relating to certain explanatory variables. See fig. la, 1b, 1c. 2. The exposure distribution obtained by area monitoring does not correspond to any type of distribution. If the results of personal monitoring are taken as a reference, area monitoring tends to underestimate the high exposures and overestimate the low exposures.See fig. 2. 3. [a]-energy exposures are underestimated when calculated from radon exposures and the equilibrium factor found in the considered mines. This is due to episodes or to zones of high radon concentrations not registered

Jan 1, 1981

By K. C. Ko, M. D. Bunnell

The studied coal mi1e is an underground coal mine located in the northern Wasatch Plateau of central Utah (Figure 1) . Since operation began in 1981, in situ stress conditions have been encountered which differ from the assumed conditions utilized during early mine design efforts. Geologic structures also varied somewhat from those projected during initial geologic interpretations of the area. The encountered geologic conditions combined with the unusual stress conditions prompted a combined study of in situ stress and stress-related geologic structures. The study was conducted in two phases, with phase 1 consisting of detailed underground mapping and analysis of stress-related geologic structures to determine stress orientations from which they originated; and phase 2, consisting of over- coring two sites within the mine to determine present in situ stress orientations and magnitudes. GEOLOGIC ANALYSIS Three types of geologic structures have been encountered in the mine that act as indicators of stress orientations of the geologic past. Two of these structures, faulting, and igneous dikes, are directly measurable in the mine. A third type of structure, photolineation, was detected through remote sensing methods and shoe god correlation to roof conditions in certain areas of the mine. Faults Two major orientations of faulting have been encountered in the studied coal mine, including a system of N 80 W striking normal faults and a system of N 55 to 70 W striking oblique-slip faults. Only data collected from the oblique-slip faults were used for this study due to the fact that these faults offset the N 80 W faults wherever the two systems intersect, indicating that the N 55 to 70 W system was created by a more recent stress field. Figure 2 shows locations within the mine where data were collected from seven locations along oblique-slip faults. Data collection consisted of measurement of fault plane strike and dip, fault slickenside trend and plunge, and slip direction. The data are tabulated in Table 1. The fault data were then plotted on stereo nets to determine the stress orientations present at the td of faulting (Figure 3). The determined stress orientations are 32~0 included in Table 1. The stereo net plots show average principal stress orientations of: 1) [ ] plunge 1 degree. These data suggest that the N 55 to 70 W oblique-slip faults were produced by a nearly

Jan 1, 1986

By A. Redfern, B. G. D. Smart

The ultimate objective of the development work presented in the paper is to devise an appropriate method for relating powered support specification to geological conditions and mining practice, thus enabling the longwall method of coalmining to be successfully implemented throughout the varied coalfields of the world. The paper begins with a review of various methods previously used to determine support rating, each method being analysed with regard to its source, the logic and theory which constitute the method, and subsequent recommendations. An alternative approach is then proposed, the Powered supports being considered to be one of three foundations, sharing load with coal ahead of the faceline which acts as another foundation, and the waste behind the supports which acts as the remaining foundation. The load/deflection characteristics of the coal and waste, which in turn are related to geological conditions and mining practice, are shown to affect the load transfer on to and hence the specification of the powered support. In particular the characteristic of the waste foundation is shown to be affected by the caving mechanism, an alternative form to that mechanism accepted for British conditions being proposed and designated "parting-plane-controlled" caving. A finite element solution for a beam on elastic foundations was used to translate the above concepts into numerical results, these results being compared with data from Indian and Chinese operating conditions. The Indian case study examines the effect of using a conventional chock type of support in a one-web back mode when mining towards a roof break generated ahead of the face, while the Chinese case study compares measured subsidence over a longwall with "blocky" roof conditions with the model results. The comparisons are encouraging, suggesting that the approach used is worthy of further development.

Jan 1, 1986

By Alan P. Cook

Methane levels have been measured around continuous miners and compared with computer simulations of methane flow. A multi-channel data logger, reading continuously from six methanometers, has shown methane levels to vary at different positions around a continuous miner, with the cutting drum and the immediate face area not necessarily recording the highest concentrations. Methane levels in the driver's cabin are generally low compared with the return side. Computer simulations, using computational fluid dynamics, have been supported by the measured data, and have shown that methane behaviour within the first few metres of the face varies considerably for different bord and pillar development stages. Methane is diluted rapidly to acceptable levels, but the distance required for this is extended when ventilation flow to the face is restricted.

Jan 1, 1995

By George D. Lessner

I'm sure that everyone at this meeting is aware of the current problems facing the U.S. metals mining industry. Prices are depressed and expected to remain depressed for quite some time. On the other hand, industrial minerals, including talc, are doing quite well. The profitability of industrial minerals has sparked considerable interest on the part of many companies in expanding into industrial minerals. Our company is one of those actively seeking to expand its position in industrial minerals. It is appropriate that the A.I.M.E. asked me to speak to you regarding entry into the talc business. So how do you get into the talc business? Earlier speakers have explained how to locate, mine, process, and market talc, so you have the "how ton.

Jan 1, 1984

By Minerals and Materials Analysis Section

During 1996, US mines produced 319 t (10.26 million or) of gold metal valued at $4 billion. At yearend, mine reserves were estimated to be 4.7 kt (151 million oz) of gold metal. Almost all of the production was from western states. Nevada accounted for about 68% of national production. Information for this article was obtained through annual reports of mining companies, US Geological Survey (USGS) databases and other public sources. Table 1 shows production and reserves by mine. It divides the mines into two categories. These are producing mines whose primary product is gold, and producing mines for which gold is a byproduct or coproduct. The mines listed in Table 1 accounted for more than 98% of US gold production during 1996. Except the Daisy Mine, the table does not include mines that produced less than 31 kg/a (1,000 oz/year). The Daisy Mine started production in December of 1996. Nor does it contain mines whose byproduct concentrate is

Jan 1, 1997