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This paper focuses on two sites in the Mount Pleasant - McCormacks Bay area of Christchurch where residential development has taken place either within or immediately adjacent to former quarries for the extraction of volcanic rock. At the Quarry Road site less overburden was dumped on adjoining land around the turn of the century, and c.1980 dwelling and related construction took place on approximately 6 m of relatively loose fill material without the recognition of its presence or geotechnical characteristics. Subsequent settlements led to abandonment of a swimming pool and the underpinning of the 3-storey architect-designed house, whilst litigation brought by the owner resulted in findings of negligence against both the architects and engineers. At the Tramways Quarry site the Council approved subdivision of the former quarry area in the early 1980s without requiring any geotechnical evaluation of batter stability or related issues. During development it became apparent that significant blast damage had occurred to rock faces, necessitating a variety of remedial measures, and that waste materials had been dumped down faces without regard to long-term stability. Both case studies confirm the requirement for careful documentation of former quarry sites by territorial local authorities as part of their administrative function, and for detailed engineering geology and geotechnical evaluation of such areas prior to any residential use of the land.

Jan 1, 1998

By S. O. Bada

Fine phosphate feed is considered to be slime and normally disposed of as a discard in settling ponds or dumped as landfill. The purpose of this research was to establish whether commercially acceptable qualities and yields could be obtained from this material using dry separation methods. The results obtained from the electrostatic separation of <105 µm phosphate ore are presented. An existing separator was upgraded in order to improve on product and flotation concentrate recovery, to test different mineral, and to reduce particle residence time between the charging chamber and the separating zone of the separator. The operating conditions were varied according to the charges imparted to the particles in the electric field, and according to other device parameters. Parameters such as splitter position, charge reversal, rotation speed, charging voltage and separating voltage. The <105 µm phosphate feed was concentrated under both triboelectrification and inductive charging. The use of inductive charging and charge reversal resulted in a significant increase in grade for <105 µm phosphate feed, with the P2O5 grade increasing from about 12 per cent to 20.50 per cent, and a recovery of 26.30 per cent under a single stage of separation. It was found that better separation was achieved at rotation speed of 6000 r/min, -8 kV charging voltage, and 25 kV separating voltage.

Jan 1, 2012

By J. W. Adams

Two different techniques were wed to make measurements of the absolute value of electromagnetic noise in an operating hardrock mine, Grace Mine, located near Morgantown, Pennsylvania. Diesel-powered haulage equipment is used in this mine, and the electromagnetic noise environment it creates was measured to see how it differs from the environment created by electric-powered haulage equipment. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. Data are recorded using broadband analog magnetic tape and are later transformed to give spectral plots. The other technique records noise amplitudes at several discrete frequencies for a sufficient amount of time to provide amplitude probability distributions. The specific measured results are given in a number of spectral plots and in amplitude probability distribution plots.

Jan 1, 1974

By A. E. Chute

The shortage of sulfur is not only continuing but appears to be worsening, attended by steadily rising prices. At the same time emphasis on air-pollution abatement is also increasing. These two factors, a rising market and the growth of environmental attention, have encouraged producers to carefully review all possible sulfur sources. As a result, production of sulfur from hydrogen sulfide occurring in petroleum is receiving greater attention than ever before. Until about a decade ago, the practice of recovering sulfur from hydrogen sulfide separated from gases (either found naturally or generated in desulfurization of liquid petroleum) was wide1y recognized but contributed little to total free-world sulfur production. However, during the past ten years, the production of sulfur from this source has increased so rapidly that it now accounts for a substantial portion of total production. This trend shows no signs of slackening, and current forecasts predict that recovered sulfur may become the dominant source of supply within ten years, exceeding mined sulfur production. This paper is intended to list sulfur sources and relationships, and to discuss the potential of producing sulfur from petroleum. The processing involved, in addition to product storage and transportation will also be discussed along with important economic aspects of sulfur recovered from hydrogen sulfide. For many years, most of the world&apos;s elemental sulfur has been produced from salt domes, predominantly by the Frasch process. During the past decade, however, another production source has developed so quickly that it is expected to surpass the Frasch production sources within a short time. This new source lies in the petroleum gases and liquids from which dramatically increasing quantities of elemental sulfur are being recovered. In the phraseology of the trade, the sulfur so obtained is know as "recovered sulfur," a term which does not, as one might expect, include sulfur recovered from other sources such as smelter gases. The growth rate of recovered sulfur compared to that of Frasch sulfur, total elemental sulfur, and total Free World sulfur in all forms is shown in Fig. 1 Since 1963, sulfur consumption has exceeded production,with the natural result that the price of sulfurhas continually increased. The posted price reported for f.o.b. Port Sulphur, La., has risen from as low as $18 per ton in 1962 to $32.50 per ton in mid-1967. With freight and other charges, delivered prices have of course run much higher, amounting to $45 or $46 per ton on the east and west coasts. In some cases, spot sales for as much as $60 have been reported. Although it is playing an ever-increasing role in the sulfur market, recovered sulfur was originally a by-product of the removal of hydrogen sulfide from natural and petroleum refinery gases. Today, however, it is often the most valuable product of a multi-product processing facility. Since there are two major sources of recovered sulfur—production and refining processes —natural gas is included with liquid petroleum for purposes of this discussion. Sulfur from these sources is produced in the form of gaseous hydrogen sulfide which is removed from a gas stream and converted to elemental sulfur. Gases in which hydrogen sulfide occurs naturally are natural gas and the gas produced from a high=pres-sure crude=oil or condensate field.

Jan 1, 1969

By C. Legote

"This paper investigates the conditions leading to the indefinite termination of production in four critical primary panels at an underground coal mining operation, the observed shortcomings in the mining approach, and the proposed strategy to mine through the affected panels. Initial assessment of the abandoned panel conditions indicated time-dependent strata failure,(i.e. bolted roof failure overrunning intersections), which occurred from mere minutes to up to four weeks post-production, with and without prior warning of failure. This prompted the constant re-supporting of back areas, which raised safety and productivity concerns. Investigation of the initial mining conditions revealed that the failures were due to a critical combination of factors, the chief of which was isolated horizontal stress. Other factors that were initially overlooked by the mine (i.e. influence of hydraulic stress, misinterpretation of borehole data), resulted in the conditions being described as abnormal. Remedial actions were determined, and in so doing, a new strategic approach was formulated to thoroughly address all failure concerns. The four panels were explicitly planned to serve as the main intake and return airways for the recently commissioned secondary ventilation shaft, as well as providing access to millions of tons in proven coal reserves. It is thus imperative to mine the panels. A feasibility study showed that the proposed strategy set for implementation would be financially viable. Paper written as project work carried out in partial fulfilment for BEng(Mining Engineering) degree"

Jan 1, 2015

In gold ores, the range of value disclosed by ordinary mine sampling is very wide, and the number of &apos;samples required for a reliable average is correspondingly great. Even where a large number of samples is available the weighted mean value of the samplesalmost invariably exceeds the true gold content. In operating mines this disparity is overcome by arbitrary reduction of high assays until reconciliation is achieved, but it is frequently necessary, especIallyin exploration, to base an estimate or to reach a decision on a relatively small number of samples from underground openings or even on a few drill hole intersections. In these circumstances, a decisive influence may be exercised by the weight allowed to high assays and to low grade intersections, both of which events are, of course, dependent on the metal distribution in the ore. Where sufficient data are available, statistical analysis will measure the risk involved, but as this information is seldom to be had, the final choice becomes largely a matter of personal judgment.With this problem in mind, a study was made some years ago of the distribution of values in four Western Australian gold ores, with the primary purpose of learning from actual ore-bodies of differing types, something of the metal distribution in the smallquantities of ore involved in individual routine mine samples, and of the importance in each case of high assays. Adequate and suitable data were available in .four cases, in three of which high assays were of frequent occurrence due to the presence of free gold. The results give concrete expression to well known differences of metal distribution, and it is proposed, firstly to record the observed distribution; secondly to examine some of the consequences of the differences in the distributions limd thirdly, to comment, in the light of this data, on the vexed question of the treatment of high assays. Standard statistical procedure was employed in the compilation of the data. The assays were classified by value into groups, each group covering a range of value of 1 dwt. per ton. Assays of less than 1.0 dwt. per ton form the first group; assays equal to or greater than 1.0 dwt. and less than 2.0 dwt. comprise the second group; those equal to or greater than 2.0 dwt. and less than 3.0 dwt. appear in the third group; and so on. Where the number of samples is large, it can be assumed that the mid-value of the group is the mean value of all the samples in the group, thus the mean values of the first three groups are 0.5 dwt., 1.5 dwt. and 2.5 dwt. respectively.The number of samples in the group is the frequency of the group, but for convenience of plotting this frequency is converted into percentage of all the samples in the series. Plotting percentage frequency as ordinate against dwt./ton as abscissa results in a frequency curve-a curve showing the frequency...

Jan 1, 1950

Appropriate roof control is the most important requirement in underground coal mining and, in the case of longwall panels or second mining in room and pillar extractions, this can be simply expressed in terms of good and predictable roof caveability. Studies of roof caveability have been undertaken in many coalfields around the world. Most of their conclusions. however, are directly related to the mining and geological conditions experienced in these areas and as a result, may not be applicable to the conditions encountered in the Appalachian coalfield. Furthermore, some of these studies appear to be theoretical and conceptual, ignoring many important parameters of the geological environment, whereas others rely heavily on geological information but lack a rigorous foundations upon which quantitative design guidelines can be built. The objective of this study is to analyze caving and mass deformation characteristics above longwall panels in Appalachia and includes: - Analysis of the effects of the geological and geomechanical characteristics of the strata on the caving height and the bulking of the caved-material. - Testing of the applicability of the various theoretical and empirical models of roof caving. Formulation of a numerical around- deformation model for ion-elastic material behavior.

Jan 1, 1986

By D P. Sainsbury, B L. Sainsbury, A Vakili, H-D Paetzold, P Lourens

The cave propagation behaviour of a jointed rock mass is strongly governed by the unique nature of joints and discontinuities, together with the intact strength of rock bridges that make up the rock fabric. A discrete finite difference (DFD) modelling technique has been developed to allow for the detailed consideration of the rock mass structural fabric at many scales and through many different stress paths that can be used for complex mine-scale analysis. The DFD methodology uses interfaces to explicitly represent large-scale structures and ubiquitous joints embedded within the simulated rock mass matrix to characterise intermediate structures. Through simulated testing of DFD materials, properties such as strength anisotropy and scale effects can be obtained. This paper discusses the successful application of implementing a DFD modelling technique for the back-analysis of caving-induced subsidence behaviour of Lift 1 at the Palabora mine.CITATION:Sainsbury, D P, Sainsbury, B L, Paetzold, H-D, Lourens, P and Vakili, A, 2016. Caving-induced subsidence behaviour of Lift 1 at the Palabora block cave mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 415–426 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J. L. Morning

During recent years, the Bureau of Mines has conducted an extensive investigation of the materials for making iron and steel. This work includes iron ore concentration, agglomeration, direct reduction of iron ores and concentrates, the production of pure manganese, chromium, and cobalt by electrolytic processes, the production of ferroalloys from low-grade domestic ores, and the development of special alloys to utilize these products. As a part of this general program, a Congressional appropriation allowed the con¬struction of an electric-furnace, semicommercial, ingot-producing plant at Shasta Dam near Redding, Calif. The primary objectives of the pilot plant were to determine the costs and operating problems involved in the production of steel and ferrous alloys in which sponge iron was used as melting stock, and to determine the physical properties of the materials produced. The pilot-plant equipment and the results of sponge iron-melting tests in the basic lined, electric arc furnace have been reported in previous publications.3/4/

Jan 1, 1953

By Dennis W. Boehm

The building boom of the late 1970&apos;s and early 1980&apos;s has all but used up most of the better sites across the more populated metropolitan areas of the United States. This means that current buildings and other types of structures are being founded on more marginal sites. The use of marginal sites has placed ever-increasing quality control on the installation of the deep foundation systems utilized for these sites. Several remedial techniques are available for the repair of the deep foundation systems. These include minipiles, compaction grouting and jet grouting. Eight case histories are cited where these methods have been utilized to repair deep foundations.

Jan 1, 1999

By Y. L. Sun

The feasibility of using the ultrasonic wave attenuation method for measuring in-situ stress is examined theoretically and experimentally. The theoretical analyses show that for a given rock type the relation between stress and attenuation coefficient ratio can be approximated closely by second-order polynomials. Combining the elastic and statistical theories, the magnitude and direction of the existing principal stresses can be predicted by using the relations between stress and attenuation coefficient ratio obtained in the calibration of core specimens. Several experiments are conducted in the laboratory on two types of rock. The experimental study consists of two parts: the attenuation-coefficient measurements in core specimens under uniaxial stress and the attenuation coefficient measurements in boreholes drilled through blocks of sandstone and limestone subjected to uniaxial compressional stress. Compressional waves are used exclusively in the measurements.

Jan 1, 1989

By E. G. Valdez

Three cryogenic systems that utilized liquid nitrogen, dry ice, and methanol with dry ice were investigated in conjunction with crushing and classifying techniques. The systems were used to aid in separating and reclaiming the metallic components contained in insulated wires, shredded automobile nonferrous metal concentrates, small motors, generators, and rubber tires. Wire strands, 2 to 6 inches long and insulated with polyvinyl chloride and neoprene, were chilled at -60° and -195° C, then roll-crushed and processed by water elutriation; this procedure resulted in two products--a sink fraction that was 99 percent metallic and a float fraction that was 99 percent nonmetallic. Excellent separation of zinc die-casting alloys from copper and aluminum contained in shredded automobile nonferrous metal concentrates was attained by chilling at -72° C for 1 minute, crushing in a grateless hammer mill, and screening. From the screened products, 97.2 and 100 percent of the copper and aluminum, respectively, were recovered in the plus Pinch fraction, and 100 percent of the zinc was recovered in the minus 1-inch fraction of over 97 percent zinc die-cast purity. Laboratory experimental results comparing direct and indirect chilling indicated that a sufficiently low temperature could be attained by indirect chilling to permit use of a liquid C02-dry ice system on insulated wires and mixed nonferrous metallic concentrates.

Jan 1, 1973

By O. F. Oxtoby, J. E. Olsen, M. W. Erwee, Q. G. Reynolds

"The extraction of molten products and wastes through smelting furnace tap-holes during the tapping process is a complex procedure involving many coupled thermophysical effects. Insight into the fluid flow behaviour in such systems can be gained by using computational mechanics tools to build highfidelity models of the fluid flow and other relevant physics. Previous work using such models indicates that the nature of the flow in the tap-hole, as well as operational parameters such as the tapping flow rate, depends strongly on the properties of the material being tapped and the geometry of the tap-hole channel. Additional complications arise when multiple fluid phases (for example, slag and metal) are present simultaneously, when porous coke beds hinder flow to the tap-hole entrance, and when the geometry of the tap-hole changes over time due to cycles of wear and repair. In the present work, challenges with the coupling of phenomena such as multiphase flow and porosity into computational fluid dynamics methods for tap-hole modelling are discussed in the context of electric furnaces used for ferromanganese production. Qualitative and quantitative results of computational models of flow through tap-holes are presented and compared as a function of material parameters to determine sensitivity effects, and in response to operational parameters to determine typical process behaviour over the duration of a tap. IntroductionPyrometallurgical production using electric furnaces accounts for substantial portion of the world supply of ferroalloys and other strategic materials (Degel et al., 2015). A range of different furnace designs may be used depending on the metallurgical process, with circular three-electrode submerged arc furnaces (SAFs) powered by alternating current being the most common for commodities such as ferromanganese and silicomanganese (Olsen, Tangstad, and Lindstad, 2007).As shown in Figure 1, manganese furnaces typically operate with a deep charge consisting of an upper layer of loose burden (onto the upper surface of which is fed solid raw material), a molten slag layer partially or completely filled with unreacted carbonaceous reductant (generally metallurgical coke), and a molten metal layer which settles to the bottom of the furnace due to its high density. The solid particles present in the slag and burden layers form porous beds which hinder the fluid flow of molten process material and gases inside the furnace (Olsen, Tangstad, and Lindstad, 2007).In order to remove material from the furnace during normal operations, a single tap-hole is built into the sidewall of the vessel near to the level of the hearth. Tapping involves removing both slag and metal phases through the same tap-hole channel, which makes tap-hole design, operation, and maintenance particularly complex. In the case of processes such as ferromanganese, which operate with no external gas injection or open arcs present at the furnace electrodes, flow of material out of the tap-hole is driven primarily by the hydrostatic pressure generated by the weight of the solid and liquid phases above the tap-hole."

Jun 1, 2019

By Konstantinos Modis

According to recently established theoretical analysis and under certain conditions, a critical sampling density can be determined for an earth-related space-distributed natural variable. Sampling above this critical limit adds little to the mapping results. The objective of this paper is the application of the above theory to the Sesklo clay quarry in Greece, where Heracles General Cement Company had conducted a sampling campaign to estimate its reserves. The structural analysis of Al2O3 values generated a variogram model, from which the critical sampling density was identified. This critical number was by far lower than the existing sampling density. Clay reserves were then estimated using geostatistics and inverse distance squares in different data schemes with variable densities. The results of the comparisons between the various models revealed that, when the sampling density was greater than its critical value, geostatistics and deterministic interpolation gave similar estimations, which is also in agreement to the theory. The optimal sampling grid finally proposed here, will result to significant cost savings in the next drilling program which is now in plan by the company.

Oct 1, 2009

By D. Grgic, A. Giraud, F. Homand

RESUME : Le comportement mécanique partiellement saturé du minerai de fer a été étudié à partir d’essais de compression simple sur des éprouvettes à pression capillaire imposée par les solutions salines. Les échantillons restent peu saturés (32 %) même pour une humidité relative de 94 %, du fait de la présence de mésopores. Jusqu’à 90 % d’humidité relative la résistance diminue régulièrement. De 90 % à 94 % une forte chute est observée et pourrait être liée à la fois aux effets capillaires et à l’hydratation de certains minéraux. Le cycle hydrique subit par la roche dans la mine a été modélisé en 1D à l’aide d’un code de calcul entièrement couplé pour les milieux poreux partiellement saturés. Les calculs ont montré notamment une diminution importante en paroi des contraintes totales au cours de la phase de désaturation et une augmentation importante au cours de la phase de resaturation. Ces variations pourraient induire un endommagement du massif et être à l’origine d’instabilités, et soulignent l’intérêt d’une modélisation avec une géométrie plus adaptée. MOTS-CLEFS : mines de fer, partiellement saturé, pression capillaire, résistance, modélisation. ABSTRACT : The partially saturated mechanical behavior of iron ore has been studied from uniaxial compression tests on samples in which the suction is imposed with aqueous solutions. Samples are little saturated (32 %) even for a 94 % relative humidity because pores are too large. Up to 90 % relative humidity the strength decreases regularly. From 90 % to 94 % a great decrease is observed ; it could be explained by the capillary effects and the moisturizing of some minerals. The hydrous cycle imposed to the rocks in the mine has been modeled with an 1D fully coupled code for partially saturated porous media. The computations have shown an important decrease in the total stresses at the wall during the desaturation stage and an important increase during the re-saturation stage. These variations could induce a rock mass damage and instabilities, and highlight the necessity of a modeling with a well-adapted geometry. KEY-WORDS : iron mines, partially saturated, suction, strength, modeling. ZUSAMMENFASSUNG : Das mechanische Verhalten von teilweise gesättigten Eisenerz wird durch einachsige Druckversuche untergesucht. Die Prüfkörper haben einen durch Salzlösungen gestimmten kapillarischen Druck. Sie bleiben kaum gesättigt (32 %), sogar bei einer relativen Feuchtigkeit von 94 %, aufgrund der Anwesenheit von Mesoporen. Bis eine relative Feuchtigkeit von 90 % verringert sich gleichmässig die Druckfestigkeit und zwischen 90 % und 94 % merkt man eine starke Abnahme in Verbindung, möglicherweise, mit kapillarischen Effekten und Hydratation von bestimmten Mineralen. Die nümerische 1D Modellisierung des gezwungenen Wasserzyklus im Stein der Mine ist mit einem für porösen Medien ganz vernetzten Rechnungcode geführt. Sie zeigt besonders ein bedeutendes Sinken der Gesamtspannung während der Entwässerung und eine bedeutende Steigerung während der Sättigung. Diese Veränderungen könnten die Beschädigung des Gesteines herbeiführen und die Grundlage von Unstabilität sein. Sie unterstreichen die Wichtigkeit eine Modellisierung mit einer gut geeigneten Geometrie. STICHWÖRTER : Eisenminen, teilweise gesättigt, kapillarischer Druck, Druckfestigkeit, Modellisierung.

Jan 1, 2003

By Richard F. Hewlett

The purpose of this Bureau of Mines paper is to provide the mineral industry with current information on high-speed data processing and to illustrate how some of these techniques can be applied to the industry. The need for applying these techniques is generally recognized, but not much information is readily available on specific applications. This paper briefly describes high-speed data processing and reduction equipment in an effort to familiarize the reader with the functions of the equipment. A list and explanation of some of the possible applications of high-speed data processing for the mineral industry are included. A few of these applications are illustrated by the use of specific examples of existing computer programs or processing methods, including their calculation times and costs. Some of the programs cited herein were developed by the author at the University of Arizona for a Masters thesis in mining engineering. When a reference is made to a specific computer, the reference is given to make the information that is being presented as factual as possible; most of the manufacturer&apos;s equipment that is mentioned in the references was available at the University of Arizona, and no specific endorsement of that manufacturer is intended.

Jan 1, 1962

By Gabriel S. Esterhuizen, Anthony T. Iannacchione

The roof rock in underground limestone mines in Northern Appalachia can be subject to high horizontal stresses in spite of the shallow depth of the workings. The high stresses can cause roof stability problems. The National Institute for Occupational Safety and Health staff have observed a distinctive asymmetrical mode of failure at the pillar-roof contact in two underground stone mines, which is different from the typical failure mode observed in response to excessive levels of horizontal stress. A dip of greater than 5° was identified as a possible cause of this mode of failure. Numerical model experiments showed that an increase in the dip of the workings can cause an increase in the stress at the up-dip corner of the roof beam. A case study is presented in which failure at the pillar-roof contact was observed where the dip of the workings was 7° in a high horizontal stress field. Numerical modeling showed that the relatively small dip of the workings could have induced stresses changes in the immediate roof that would explain the failures. The model results also showed that this mode of failure is less likely to occur if the limestone pillars contain weak bedding planes that provide stress relief. In addition, the results showed that for the conditions at the case study site, the stress in the roof beam was not sensitive to the thickness of the roof beam or to the excavation span. The high horizontal stresses at this site are an important contributing factor to the observed failures.

By Narendra N. Khatri, Michael Deutscher, Jozef F. Zurawski

Five sewer connections were required to divert Combined Sewer Overflow (CSO)from existing outfalls to an old underutilized large diameter brick sewer (the Easterly Interceptor). The connections were part of an on-going CSO control program by the Northeast Ohio Regional Sewer District (NEORSD) in the City of Cleveland, Ohio. Each connection was made by pipejacking and hand-mining a fiberglass-reinforced polymer (FRP) pipe through soft glaciolacustrine clays and silts. Jet grouting was utilized to stabilize the soils and fill the voids surrounding the interceptor prior to making the underground connection. Reinforced concrete liners were constructed inside the aging brick sewer to provide structural stability during ground improvements and connection work. The project also involved micro tunneling two approximately400 foot lengths of FRP pipe through soft ground using a slurry pressure balanced machine.

Jan 1, 2005

By C. D. K. Gauert

High-pressure waterjet technology is proposed as an alternative tool for selective underground mining of high-grade ore sections in stratiform orebodies showing a preferred ?bottom? or ?top? enrichment such as the Witwatersrand reefs and the Bushveld Complex platiniferous reefs. This technique, utilizing known mining technology together with more advanced machinery and additives as used in industrial and cleaning applications, may lead to an increased life-of-mine (LOM) for mining operations. A series of experiments was successfully carried out in a laboratory on Witwatersrand quartzite material, indicating acceptable cutting performance. Mining volumes by selectively cutting of reef portions are considered to be comparable to traditional drilling and blasting. Economic advantages of waterjet mining include energy savings due to the lower quantity of gangue rock to be hoisted to surface, as well as savings by a decrease in the usage of blasting materials. Capital expenditure of waterjet cutting, if applied on a broad scale, could be lower in the long term than that of conventional drilling and blasting methods. Mining by the application of high-pressure waterjet technology could become a competitive ?green technology? improving the economics and safety of labour-intensive mining operations. This paper suggests that waterjet cutting at an industrial scale can become a routine hard-rock mining technique in the future. Keywords waterjet cutting, high pressure, mechanized narrow reef mining, abrasive agents, costs, selective mining.

Jan 1, 2013

By M. John Brodie

This report reviews the regulatory environment as it pertains to tailings management and disposal from mining operations, excluding coal and placer gold operations, in the state of Alaska. It is based on the EPA&apos;s staff position on an effective program to regulate mining wastes as presented in the May, 1990 Strawman II document, The unique conditions which occur in parts of the state, including a fragile environment, high seismicity and permafrost, are identified. The special waste management practices which are necessitated by these conditions are delineated. The report provides a detailed outline of the current technologies that are suitable for designing, constructing, operating and closing a railings disposal facility to meet environmental protection objectives. Cost implications to the mining industry of potential regulatory actions, such as the degree of groundwater protection are examined.

Jan 1, 1992