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By Braithwaite J. C

A brief summary is given of the applications of geochemistry on two areas in North West Nelson. It has been found to be an effective method for reconnaissance prospecting. Its particular advantage lies in areas which due to thick bush cover or ru

Jan 1, 1980

By Kot F. v. Unrug

The depletion of thicker coal reserves has resulted in the thinner seams being economically attractive. Surface protection against subsidence limits the extraction ratio to 50% for the room and pillar method as a "no subsidence condition". That rule was developed for pillars with smaller width/height ratio because seams mined at the time were commonly 6 feet thick. Over time pillar ribs deteriorate around the pillar perimeter and thus decrease the area of the pillar. Using 50% extraction as the no subsidence condition in the squat pillar category (below 42 in with w/h > 7) causes unnecessary losses of reserves because squat pillars are stronger. In this paper a method is presented for design of long-term pillars. Based on the analysis of pillar deterioration and field observations, an increase of the "no subsidence" extraction rate to 60% for squat pillars is proposed.

Jan 1, 2001

By R. Van Hille, A. E. Lewis

"The precipitation of a selection of metals from both a synthetic and an actual metal-rich effluent was investigated. The experimental aspects of this study were carried out in a two-stage process consisting of a pre-treatment clarifier and a fluidised bed (pellet) reactor. Each unit operation in the two-stage process was investigated separately. The pretreatment clarification stage at pH ˜ 5 resulted in a 99.9% removal of iron and 97.3% removal of aluminium.The pellet reactor was used to precipitate nickel as nickel hydroxy-carbonate from a pure stream and a removal efficiency of 99.6% was achieved. The high local supersaturation at the reagent inlet points caused the formation of a large amount of fines, but these agglomerated onto the pellets up the length of the bed (See Figure 1).For copper precipitated as copper sulphide from a pure stream, a maximum removal efficiency of 92% was achieved. The high local supersaturation at the reagent inlets also caused the formation of a large amount of fines, but the extremely sparingly soluble nature of copper sulphide meant that the fines were not agglomerated up the length of the bed. In Figure 2, the global supersaturation ratio was relatively low, and thus there is little homogeneous nucleation and degree of fines formation. However, the fines occurring after the third sulphide input point (at 30cm from the bottom of the bed) indicate that local supersaturation also plays a critical role in fines formation. It was therefore concluded that, for the copper sulphide case, it is essential to control the supersaturation at the inlet points in order to prevent fines formation altogether, as it is not possible to agglomerate the fines once they exist in the bed."

Jan 1, 2003

By Robert B. Parsons

"Considering the traumatic events of Canadian mining taxation of the 1970s, one wonders at the sanity of anybody who tries to predict what the 1980s might hold for the tax structure of the mining industry. Yet, the author agreed to tackle this task when called upon to do so at the annual meeting of the Quebec Metal Mining Association in June. The text of this ""daring"" speech follows.IntroductionI have been asked to play the part of the oracle at Delphi, and to predict what the 1980s might hold for the Canadian mining industry in terms of taxation. To appreciate the challenge of this difficult assignment, try to imagine someone in my position back in 1972 attempting to forecast the balance of the 1970s. I daresay that ten years ago nobody could possibly have conceived of the devastating and casualty-ridden rollercoaster ride that mining taxation actually took in the 70s. Nevertheless, I shall examine the entrails and try to shed some light on what might happen during the balance of this decade as far as mineral taxation is concerned.If one were to retreat deep into history, one would find that taxation generally served one purpose-namely, to raise revenues for the government. More recently, an important second function has emerged: taxation is increasingly being used as a fiscal tool-a tool intended to mould and shape future events in order to accomplish certain economic, social and political objectives. It is these two main forces-the need (or desire) for revenues and the perceived convenience of using taxation as a fiscal tool-which will continue to shape the tax structure of the future.In our assessment of where taxation of the mining industry may be headed, we should be able to learn something by looking at where we have been."

Jan 1, 1982

By Charles M. Wilk

"Mass stabilization (MS) is a ground improvement technique that can prepare areas of low bearing strength soil for subsequent infrastructure development. The technique involves mixing binding agents such as portland cement, fly ash, slag, or lime into the subject soil while the soil remains in-place (insitu). The binders “cement” the soil grains together to form a cement modified soil or a soil cement. The MS-treated area now has improved bearing capacity to support infrastructure or to prevent movement of the material such as landslides.The same insitu soil mixing technique can be used to address contaminated areas. Binders or reagents are mixed into soil. The treatment protects human health and the environment by immobilizing hazardous constituents within the treated material. When used for the purpose of environmental remediation the technology is called Insitu Solidification/Stabilization (ISS).Both Mass Stabilization and ISS treatments require laboratory studies to develop a mix design of soil and binder(s) that produce the desired physical and/or chemical properties. The mix design is then transferred into the field. Successful MS and ISS treatments rely on reproduction at full-scale of the mix design and the thorough mixing attained at laboratory scale. Fifty to 70% of the cost of a MS or ISS project is in the cost of the binding agent that is to be mixed into the subject soil. Under-dosing, overdosing, non-thorough mixing, and mixing in the wrong areas all create cost over-runs.This paper will discuss recent innovations in mass stabilization systems that improve the cost effectiveness of the treatment technology. Specialized equipment can impart greater mixing shear thus improving the thoroughness of mixing. Dry powder pressure feeders can conserve the “drying capacity” of binder resulting in higher strengths at lower binder dosages. Global Positioning System (GPS)-based systems can guide the mixing operator for complete mixing coverage. An integrated tracking and feeding system can record that proper dosing and mixing was accomplished and generate construction QA/QC reports for the client.INTRODUCTIONNew or expanding infrastructure projects may encounter areas of low bearing capacity soil or areas where marginal materials such as waste, dredged material, or sediment have been placed. Mass stabilization is a geotechnical method that can be used to improve the bearing capacity or stiffness of soil. Mass stabilization involves mixing binding agents into soil subject to treatment while the soil remains in-place or insitu.Mass stabilization technique can also address contaminated soil therefore, the same technique can be used to attain both civil and environmental engineering goals. In this environmental application the technology is known as insitu solidification/stabilization (ISS). ISS protects human health and the environment by immobilizing hazardous constituents within the treated material."

Jan 1, 2015

By John F. Havard, Armine F. Banfield

Sooner or later, we all get involved in the economic study and valuation of a mineral deposit. To communicate clearly the necessary information, we must scrupulously use various terms with specific meaning. All these terms-such as ore, exploration, development, production, reserves, proven ore, probable ore, possible reserves, resources, as well as similar terms applying to coal-are continually on the lips of anyone who reports on the economic aspects of a mineral deposit at the exploration, development, and production stages. The meaning of these terms is even more important in feasibility studies to determine whether a deposit should be put into production. Finally, careless use of these terms in reports published for public financing may, and sometimes does, lead to prosecution of the writer for misleading information.

Jan 7, 1975

By Charles E. W. Bateson

The Mojave mining district is situated in a group of small hills centering around Soledad peak, in the Mojave desert, Kern county, Cal. These hills are about 4.5 miles SSW. of Mojave, a railroad town at the junction of the Santa Fé and Southern Pacific railroads. The town of Mojave is about 50 miles north of Los Angeles, to which it is connected both by telegraph and by rail. The distance on the Southern Pacific railroad is 102 miles, covered in 3 hr. and 45 min. by express train. A sketch-map of this region is shown in Fig. 1. The Mojave district is relatively isolated. The only other mining towns in this section of California are Randsburg and Johannesburg, in a district (containing the well-known Yellow Aster mine) at the northern end of a low range of hills, which begins about 20 miles NE. of Mojave, runs nearly N. for 35 miles, and varies in width between 3 and 6 miles. As will be seen later, the origin and formation of these hills are not the same as those of Soledad peak. II. Climate and VEgetation. The climate and vegetation of the Mojave district are typical of the arid regions of the southwestern United States. During the winter and spring there is some rainfall, and the tempera ture is generally from 60" to 70" F. in the day-time. The rainfall in the spring is often very considerable for short spaces of time, and cloud-bursts are not infrequent. In summer there is continual sunshine, with temperatures, as a rule, exceeding 100" F. in the day-time, while 115" F. in the shade of a house is not at all unusual; but at night the temperature falls considerably. No rain falls during the summer. The vegetation

Jan 1, 1907

Uranium, the object of a quarter billion-dollar search in the US during 1977, is a ubiquitous element rarely found in economic concentrations. It originates in magmas as a large tetravalent ion, the size of which restricts it from the crystal lattices of many rockforming minerals. Instead, according to United States Mineral Resources (US Geological Survey Professional Paper 820) as the magma crystallizes, a portion of the uranium is deposited as an intergranular film on rock forming minerals, enters accessory minerals, or forms its own minerals. The remaining uranium becomes concentrated in magmatic differentiates, where it forms minerals in pegmatites and veins.

Jan 10, 1978

By Alvin Kaufman

ANTHRACITE mining in the United States is concentrated in a 480 sq mile section of north- eastern Pennsylvania. The producing area is broken up into four fields, known as the Northern, Southern, Eastern Middle and Western Middle fields. These areas represent intricately folded coal measures in synclinal residuals left by erosional forces. Destruction by erosion has eliminated some 95 pct of the original coal. However, discounting the 5 billion tons removed to date, 8 billion tons are believed to be still recoverable.

Jan 3, 1953

By Frederick P. Schwarz

Sample preparation and analysis can impose devastating errors on assay data. Minimizing these errors by testing and procedural redesign may be critical to assure representative assays and project success. Replicate samples, taken at any volume-reduction and/or analytical step in a sampling procedure, generate replicate assay values whose relative differences constitute a set of data. Variance of this data judges the addition to total sampling error imposed by the step generating the replicates. A variance more than (11.5%)' is excessive for a single step. Sample volume increase and/or comminution at a step will reduce variance for that step. Rejects from well mineralized intercepts can provide bulk samples for testing.

Jan 1, 1989

By John A. Emery, Frank G. Snyder

MINING geology has a threefold objective: to guide prospecting for new ore, to evaluate known orebodies as development risks, and to supply the detailed knowledge of ore structures necessary for more economical extraction. The role of geology in exploration is well established. This article will deal solely with orebody evaluation and the application of geology to development and mining problems as practiced by St. Joseph Lead Co. in the southeast Missouri district, which for many years has supplied approximately 30 pct of U. S. lead production. The primary concern of the present discussion is geology in the district, not geology of the district. The southeast Missouri district, locally called the Lead Belt, includes parts of St. Francois, Madison, and Washington counties. The first recorded mining was about 1720 at Mine La Motte in Madison County on surface showings of lead ore. Later discoveries near Bonne Terre, twenty-five miles to the north, led to extensive prospecting and underground mining. To date the district has yielded well over 8 million tons of pig lead, valued at more than $1 billion. By far the greater part of the lead production has come from an area of 50 sq miles, centering on the city of Flat River, as shown in Fig. 1. Role of Geology in Metal Mining The history of the use of geology in the older metal mining districts follows a simple consistent pattern that may be considered in terms of four distinct phases. Each geologic phase is a response to the economic status of the mining district; each has definite characteristics setting it apart from other phases; and each passes into the succeeding phase as the mining operation gradually exhausts the large, rich, easily discovered deposits and lives upon increasingly smaller, lower grade orebodies that are less easily found. The geologic phases and their major characteristics are as follows: Period of No Organized Geologic Program: During the early history of a great metal district ore is easily found by random prospecting and wildcat drilling. Many small operators are active, as profitable mining can be done with a relatively small capital outlay and a minimum of technical staff. Mining practice consists largely of sinking a shaft on an ore showing and following the ore in sight. When the ore is exhausted or becomes unprofitable to mine, the process is repeated on a new ore showing. The miners become familiar with certain ore habits and use this practical geologic knowledge to guide mining. The method is successful as long as large tracts of virgin mineralized area are available. This phase ends when small-scale mining methods are no longer profitable and the mines become consolidated into the hands of a few operators.

Jan 1, 1957

By Richard L. Stowe

Four NX-diameter holes were diamond-drilled in competent granite. Samples of the recovered core were used in laboratory tests. A borehole, plate-bearing device known as a Goodman jack was used to perform load deformation tests on the rock in the core hole. The majority of samples used in the laboratory tests were taken from depths in the hole at or within 5 ft of those at which the plate bearing tests were made. Borehole camera records, compressional and shear wave velocities, and densities were measured. Dynamic elastic constants were computed for the in-situ material, while comparative data (except camera records) were obtained in the laboratory. These data were examined to evaluate the significance of the in-situ modulus of deformation (Ed), the value computed from Goodman jack tests. Average test results show an excellent correlation between in-situ and laboratory data. The ratio of laboratory to field deformation modulus ranges from 9.82 to 7.21 for 3,000 and 9,000-psi stress levels, respectively. The dynamic modulus ratio, ED field/Ep lab, is 1.02; the compressional wave velocity ratio, V8 field/V8 lab, is 0.94; the shear wave velocity ratio, V, field/V, lab, is 1.12; and the density ratio, field [y/y] lab, is 0.95.

Jan 1, 1973

By F. P. Dewey

RICH HILL is situated in the famous car-wheel iron region of Southwestern Virginia, and although it contains many iron ores, this paper will be devoted chiefly to its car-wheel ore. Geologically, Rich Hill is somewhat difficult to describe, as the strata of the region are seriously folded and contorted. It lies at the base of one of the primordial spurs of the Blue Ridge, the ore appearing as a sedimentary deposit on the limestone No. 2, sometimes showing an imperfect stratification, but generally being an

Jan 1, 1882

By R. E. Gundersen

Hydro-power-the use of high-pressure water as an energy source-offers tremendous benefits for environmental control in deep, hot mines. The extent of these benefits depends on the mining method, the selection of equipment to be hydro-powered, and the efficiency with which the coolth is extracted from the water and into the working environment. The engineering of hydro-power systems continues to receive much attention. However, this paper considers the environmental implications of using hydro-powered equipment, particularly with regard to positional efficiency. The integration of hydro-power with developments such as backfill, mechanization, and higher face-advance rates is discussed. Layouts are proposed that attempt to minimize the quantity of water in circulation by extracting the maximum coolth from the water.

Jan 1, 1990

By Marino Carrión P

Ante la crisis ecónomica que afecta al sector minero, este ha previsto expandir su producción y reducir los costos operativos que le competen. En esta perspectiva, la Compañía minera Atacocha busca ampliar su rango de producción a partir de la elaboración de un proyecto racional del ore-body Santa Bárbara. El proyecto consiste en explotar el cuerpo mineralizado por encima del nivel 400. Sin embargo, las condiciones para la mineralización son insuficientes. En este sentido, el presente texto presenta una alternativa de explotación mecanizada donde el cuerpo mineralizado tolere los niveles altos de temperatura a través de un nuevo block que se aplique en la profundización del ore-body y puede minimizar los costos operativos que esto conlleva.

Apr 1, 1991

By A. J. Farstad

Recent advances in microcomputer technology have opened the way for systems which can track the location of underground mining personnel from the surface. A computerized system has been designed which is capable of not only tracking the location of the miner but also of monitoring underground parameters, communicating between work stations and sounding alarms when underground conditions are judged to be unsafe. For the system described herein, the locations of the underground personnel are detected by a network of underground terminals which routinely emit RF pulses to interrogate miniature transponders worn by the miners. Each transponder is uniquely programmed to delay its response in such a way that the RF terminal can identify the individual transponders by the time slots in which the responding pulses are received. The underground terminals are then interrogated by the host computer on the surface which keeps a running account on underground mine conditions and personnel. The underground portion of the system is designed to operate even during mine emergencies, deriving its power from rechargeable battery supplies which are float charged during normal operation. Nine mines were visited on this program and the industry reaction to the system was generally favorable. By slanting the system design for daily use in the mine, the chance of its acceptance by the industry is enhanced. Furthermore its likelihood of being operational in the event of an emergency is significantly increased.

Jan 1, 1981

Delivery of effective plant shutdowns is primary to the business success of mining and processing plant operations. This paper sets out a methodology that starts with understanding the business objectives of the shutdown and promotes rigorous detailed planning, effective communication, appropriate governance and effective participation of plant operations personnel. The result is delivery of business effective outcomes.

Jan 1, 2004

By Ketteridge IB, Mulcahy DE, Quast KB

The long term energy demands in South Australia are such that there is a distinct possibility that one of the lignite deposits in the State will be exploited to feed a pulver- ised-fuel power station. Bowmans lignite deposit is the largest lignite deposit in South Australia and is considered to be a contender. The deposit is ideally situated (100 km north of Adelaide) but the quality of the lignite is poor (see Table 1). TABLE 1

Jan 1, 1984

By L. Zeka, I. Ndala, J. Frenay, S. Gaydardzhiev

"Reductive leaching of cobalt (III) from a heterogenite bearing ore has been performed. Pyrite was added to the system and simultaneously bioleached in order to provide ferrous iron as reducing agent. Within such arrangement the iron ions are continuously re-circulated inside a Fe 3+ / Fe 2+ loop. As a result Co(III) is solubilized in the presence of Fe 2+ ions in concentrations well below the stoichiometric requirement. The ore has been initially subjected to acid pre-leaching in order to guarantee that the available Co (II) has been entirely removed. Two technological parameters have been studied to show influence on the degree of cobalt leaching: concentration of ferric iron in the inoculum and the presence of bacteria. The bacterial role could be mainly viewed in supplying ferric ions in the system which chemically react with the pyrite to generate ferrous ions used as Co(III) reducing agent. Co(III) dissolution has been less efficient when the concentration of total iron in the system was low, but also when microorganisms were absent. SEM observations on leached heterogenite have evidenced bacterial attack on the mineral; however the precise role of bacterial presence on cobalt (III) leaching is still to be elucidated.INTRODUCTIONCobalt accompanies quite often copper in secondary oxidized ore deposits (Rumbu, 2013). In such associations cobalt is found both as CoII+ as well as CoIII+ (Deliens, 1974). In contrast to cobalt (III), cobalt (II) is leached relatively easy in sulphuric acid solutions. Cobalt (III) when present in mineral form belongs to the heterogenite mineral group with a simplified chemical formulae Co2O3.H2O or CoOOH. In order to be brought in solution, heterogenite should capture two electrons, likewise shown in reaction 1 below:"

Jan 1, 2016

By Leslie Taylor, Kevin Genson

This paper reports on an experimental study of the effect that bottom shaping might have on the impulse delivered to a light armored vehicle due to a buried mine detonating beneath the center of it. The study was restricted to explosives buried in saturated sand and three parameters were varied within the study: bottom angle (0 degrees to 21 degrees), depth of burial of the explosive (1.02 mm to 12.7 mm), and stand off distance (0 mm to 38.1 mm). Six hundred and thirty six milligrams of explosive was used as the explosive load. It has been shown in previously published work [1,2] that Hopkinson scaling works well for the determination of impulse loading on a semi-rigid target plates. Therefore in terms of a full scale test using 4.54 Kilograms of explosive the parameters investigated would cover a DOB of from 19.56 mm to 243.84 mm and a Stand off distance from 0 to 734.06 millimeters. These values nicely cover those of interest to the Marines with regard to the AAV (amphibious assault vehicle). Four angles were investigated at all DOB’s and Stand off distances – 0 degrees, 7 degrees, 13 degrees, and 20 degrees. The results show that reduction in impulse delivered to the target is achieved with an angled bottom on the target plate with a major reduction occurring before the 13 degree angle is reached. Hence vehicles with quite modest bottom angles could help greatly in load reduction with very little loss in utility.

Jan 1, 2008