Search Documents

By R. Gilges

The implementation of effective techniques for meeting the maintenance requirements of the new Utah Copper Division smelter, one of the largest in the Western Hemisphere, is a goal of the smelter management and supervisory personnel. Kennecott's Metal Mining Division Computing Center has been working with smelter personnel to implement a computer program to provide instantaneous access to equipment specifications, maintenance and cost histories, spare parts, preventive maintenance scheddes, etc. for several hundred pieces of equipment. This information will be available to all smelter personnel via visual display terminals. The system will dramatically reduce the time now spent in search of pertinent information required in effectively performing the maintenance functions. It will also be used to analyze practices, detect trends, prepare budgets, and substantially reduce the paper work normally associated with the running of a large and complex maintenance organization.

Jan 1, 1977

By T. R. Ellis

The vast majority of valuations produced for mineral properties using the net present value method provide an estimate of Investment Value or Use Value. Such an estimate can be a long way from the price that the property would sell at if placed on the market. Indicators from the market need to be used to validate or modify the net present value calculation. The comparable sales and replacement cost approaches used in the appraisal of urban buildings generally fail us in the appraisal of mineral properties. Other methods of sales analysis are introduced. Guidelines for what a minerals appraisal report should contain are presented.

Jan 1, 2000

By Ronald J. Riberich

The Mineral Economics and Management Society (MEMS) held its fifth annual conference in Montreal, Quebec, Canada earlier this year. “The Minerals Industry: Responding to the Global Challenge” was the first MEMS conference to be held outside of the United States. About 125 mining- and minerals-related professionals attended. The MEMS program included six sessions and three distinguished speaker addresses. The session topics included: “Minerals in the Macro economy: Development in Demand,” “Trends in Global Metals Supply: The Producers’ Challenge,” “Global Environmental Issues: Policy Perspectives,” “Global Environmental Issues: Quantitative Analysis” and “Minerals in the CIS: Phoenix or Albatross?” A student session was also offered. It provided a competition for monetary awards for outstanding papers.

Jan 1, 1996

By A. M. Radigan, W. G. Prast

M.S. Azun The authors' paper did not explain the facts and reasons why state companies are established and what their role is in international industrial mineral trading. Also, I do not agree with the conclusion implying that the main goal for state companies is to capitilize natural resources. Almost all state companies are founded by certain laws and their activities are arranged by state regulations. Their only aim is to operate mineral deposits for their people and to protect the rights of the people. Although some ore deposits, such as nonstrategic or small, may be exploited by privately owned companies, the state has the right to control the operation and production. Activities of state companies may or may not be widened because of the character of the deposits and the importance of the mineral market involved. For some countries, although governments may occasionally change hands, the policy of the mineral trading system is not affected by this change. There is no doubt that any government desires to make more earnings to increase GNP, when it is involved in operating and trading mines. It wants to produce and sell the finished products, instead of unprocessed ones, if possible. When it is known that some mineral deposits are relatively rare, such as Turkish boron deposits, the government can nationalize the mines to control production and affect the market. If there is an abundance of a certain mineral in the market, the government can cut production and set a floor price, such as Canadian potash. Also, when production of a specific mineral is unique, such as Turkish chromite, the price of such mineral may be set by correspondant government. One may add that if some governments with their state companies produce a certain mineral in a larger amount, they may decide to establish a cartel to protect their production and price. These are the facts followed by government-owned state companies and partially government-owned companies. The reason being charge of many deposits by the state companies is always the same: "protect" the mineral rights of the people.

Jan 2, 1984

By E. Piesch, M. Urban, G. M. Hassib

INTRODUCTION In radon dosimetry diffusion chambers with passive [a]-detectors are now in current use to investigate the long-term accumulated indoor exposure of radon and daughters. For the diffusion chamber developed at Karlsruhe the electrochemical etching technique (ECE) was applied to reveal [a]-particles in polycarbonate plastic detectors. Compared to conventional etching, the main advantages of the ECE are the large track diameter, simple track counting in a single field of about 1 cm2, stability of the latent tracks to humidity and temperature and ability for a long-term accumulation up to 1 year. The electrochemical etching system was designed to etch in one run about 101 foils by using a 200 W high voltage generator. The commercial available radon dosimeter system is applied for a country wide program of measuring radon in dwellings. Because of an increasing interest of radon monitoring in mines, environmental monitoring and personnel dosimetry the properties of several track etch detectors have been studied. In the comparative study, Makrofol E, LR 115 and CR 39 were used in the diffusion chamber to investigate the etching techniques, the relative efficiency, the measurable [a]-energy range, and the counting statistic for the measurement of radon concentration. THE KARLSRUHE DIFFUSION CHAMBER The design of the Karlsruhe diffusion chamber is presented in Fig. 1. The upper part of the chamber is closed by a fibreglass filter to separate radon from aerosols, heavy dust particles and radon decay products. Inside the diffusion chamber [a]-particles from radon and daughters are detected by two passive radon detectors, one on the bottom of the chamber and the other in front of the filter. With the fibreglass filter applied the diffusion time is about 1 minute for radon. Therefore, also short-term variations in the radon concentration are recorded by the track detector. Mainly because of the short halflife of thoron (56 s) only about 7 % of the thoron concentration is expected in the diffusion chamber. Radon monitoring provides the estimation of the long-term accumulated mean value of the radon concentration with a lowest detectable concentration of 0.1 pCi/1 after 3 months accumulation by using polycarbonate track etch detectors, an electrochemical etching technique and track counting in a single field of 1 cm2. The diffusion chamber was optimized for the polycarbonate track detector with respect to chamber geometry and detector position [1]. Table 1 presents data for 3 different diffusion chamber designs. The radon sensitivity of the diffusion chamber depends on the [a]-energy discrimination and the angular response of the [a]-track detector. The difference between foil No 2 and foil No 1 can be explained by an additional plate-out effect of radon daughters on foil No 3. The high sensitivity of foil No 3 compared to that of foil No 2 is caused by an increase of the effective volume and the effective area for [a]-particle from radon and from plated-out decay products, respectively. Additional experiments have been performed in order to investigate the electrostatic properties of the plastic material and the properties of the diffusion filter [1]. The properties of bare a-detectors were compared with those inside the diffusion chamber. In contrast to laboratory results, dust particles deposited on the detector surface or in the environment of the detector obviously affect the reproducibility of the bare detector significantly. After 4 months exposure in dwellings the scatter of 10 dosimeters exposed in the same room exceeds a factor of 3 compared to 15 % for the diffusion chamber. COMPARATIVE STUDY OF TRACK ETCH DETECTORS Detector types and evaluation technique In the comparative study the properties of the following plastic track etch detectors have been applied: - LR 115 from Kodak Pathé, France, is a red dyed cellulose nitrate layer of 13 µm thickness on a 100 µm thick polyester support. The holes appears as bright spots in a dark red background. In an optical microscope counting of through etched [a]-tracks which must penetrate the detector layer - CR 39 from Pershore, England, is an ally1 diglycol carbonate plastic of about 300 m thickness. The normal etched [a]-tracks are counted by an optical microscope and the ECE [a]-tracks by a microfiche reader.

Jan 1, 1981

Commercialisation of outcomes from research projects is a process often poorly understood and managed, but has the potential to achieve significant benefits for the industry and community as a whole. JKTech Pty Ltd was established in 1986 to transfer viable research outcomes from the Julius Kruttschnitt Mineral Research Centre (JKMRC) at The University of Queensland, Australia. This paper describes successful and unsuccessful examples of commercialisation by JKTech over the years, and draws some conclusions as to the factors that contribute to success and failure in technology transfer.

Jan 1, 2012

By L. Shevenell, L. Stillings

The Acid Drainage Technology Initiative-Metal Mining Sector (ADTI-MMS) has established a Pit Lake Committee to enhance the science and understanding for the long-term management of pit lakes. Participation in this new committee is from members of federal and state agencies, industry, and academia, including numerous individuals representing 10 states. Work has begun on a pit lake literature search and review, database, classification, and sampling and monitoring procedures document. Coordination with the International Network for Acid Prevention (INAP) has been established. Future work will include preparing a prediction and assumption verification document, a report identifying variables upon which water quality is dependent, and an applied remediation technologies document, including an evaluation of the effects of backfilling.

Jan 1, 2002

By J. S. Gardner, J. J. Zaluski

I. INTRODUCTION West Virginia has a long history of coal production.1 The state at one time led the nation in total coal production, while at the same time coal from West Virginia constituted one quarter of total U.S. coal production.2 In more recent years, however, West Virginia’s level of coal production has been reduced in comparison to that of other states due to the high relative cost of producing coal in the state.3 Another blow to the producers of coal in West Virginia is the action known as Bragg v. Robertson.4 In 1998 various individual plaintiffs, as well as a conservation group known as the West Virginia Highlands Conservancy, filed a civil action under a provision of the Surface Mining Control and Reclamation Act of 1977, Pub. L. No. 95-87, §522, 91 Stat. 445 (codified at 30 U.S.C. §§1201-1328) ("SMCRA" or the "Act") that allows declaratory and injunctive relief against state and federal officials for non-compliance with the Act.5 The plaintiffs generally claimed that the Director of the West Virginia Department of Environmental Protection ("WVDEP") had exhibited a pattern of violating mandatory non-discretionary duties under SMCRA and the West Virginia state regulatory program.6 These non-discretionary duties involved many areas of regulation, including water quality standards, disturbance of wetlands, hydrologic reclamation plans, Approximate Original Contour ("AOC") requirements and AOC variances, post-mining land uses, contemporaneous reclamation, and as explained later, the "buffer zone rule."7 In addition to these claims against WVDEP, the plaintiffs also alleged that certain individual members of the Army Corps of Engineers (the "Corps") had failed to carry out statutory duties under the Clean Water Act (the "CWA") and the National Environmental Policy Act ("NEPA").8 Generally, the complaint stated that the Corps did not have statutory authority under the CWA to regulate valley fills created for the purpose of the disposal of waste material, i.e., the overburden associated with mountain top mining.9 Alternatively, the plaintiffs claimed that even if the Corps could regulate valley fills, the Corps violated NEPA by issuing nationwide permits without required analysis. Finally, the plaintiffs asserted that the issuance of a nationwide permit for surface mining valley fills is unlawful.10

Jan 1, 2001

By X. Zhu, R. Du Plessis, J. D. Miller, D. G. Kotylar

Research on the low-potential hydrophobic state of pyrite with potassium amyl xanthate (PAX) as collector, is reported to help explain and understand the fundamental aspects of the N2TEC flotation process, which was originally developed for the improved recovery of gold from refractory auriferous sulfide ores. Typically in the N2TEC process, air is replaced by nitrogen as the flotation gas, and potassium amyl xanthate is used as collector for the reactive auriferous pyrite particles. The first N2TEC flotation process was commissioned at Lone Tree in Nevada in March 1997 and has been in operation ever since. On the basis of electrochemically controlled contact angle measurements, the low-potential, low-pH hydrophobic state of pyrite has been examined as a function of flotation variables such as pH, gas-phase composition, collector concentration and pyrite potential.

Jan 1, 2000

By M. Hancer, J. D. Miller

The sign of the surface charge of selected potassium soluble salt minerals namely KClO4 , K2SO4 , KNO3, and KCl was determined from nonequilibrium electrophoresis measurements and found to be negative for each of the salt. Dodecylamine flotation of these salts revealed that the concentration of amine required for flotation increases in the order KClO4< K2SO4< KNO3<KCl. Precipitationof the amine collector colloid was not required for flotation of the oxyanion salts and in this case it appears that adsorption of the dodecylamine cation is sufficient to create the hydrophobic surface state. The order for flotation is explained in terms of surface hydration of these respective potassium salts based on contact angle measurements and FT Raman spectroscopic characterization of water structure.

Jan 1, 1999

By M. Pawlik

The rheological properties of mineral suspensions affect the design and operation of transport, mixing, size classification, grinding, gravity concentration, flotation and de-watering systems. In many cases, the rheological properties can be modified to improve processing through the addition of chemical additives. These additives may be either organic or inorganic and generally affect the state of particle aggregation or dispersion. Inorganic modifiers act primarily by affecting the surface charge of mineral particles and thus control the magnitude of electrostatic attraction/repulsion between particles. The action of organic additives (polymers and surfactants) is a combination of electrostatic and steric forces – the latter being related to the molecular weight of these reagents. While low molecular weight polymers are dispersants (viscosity reducers), high molecular weight polymers are likely to induce flocculation and increase yield stress.

Jan 1, 2004

By K. Kovári, G. Anagnostou

Slurry and EPB-shield tunnelling have been successfully applied worldwide in recent years. Under extremely unfavourable geological conditions, however, face instabilities may occur. The present paper aims at a better understanding of the mechanics of face failure. For the case of slurry shield, attention will be paid to the time-dependent effects associated with the infiltration of slurry into the ground ahead of the face. Related topics, such as the stand-up time and the effect of the excavation advance rate, will be discussed. In the case of an EPB-shield, a distinction will be drawn between fluid-pressure and effective pressure in the chamber. The effective pressure can be visualized as a “grain to grain” contact pressure between the muck and the ground at the face. The water pressure in the chamber reduces the hydraulic head gradient in the ground and, consequently, the seepage forces acting in front of the face. The face is thus stabilized both by the direct support of the pressurized muck and by the reduction of the seepage forces in the ground. The paper includes normalized diagrams which allow the assessment of tunnel face stability.

Jan 1, 1997

By M. N. Semenoff

On July 8, 1999, EPA announced the RCRA Cleanup Reforms, a set of administrative reforms designed to achieve faster, more efficient cleanups. This paper will discuss the Reforms, the status of their implementation and assess these potential impacts on the mining industry.

Jan 1, 2001

By Bernie W. Martin, Raymond Leray, Christian Criado

Aguas Argentinas,1 a consortium managed by Lyonnaise des Eaux of France and operator of the world’s biggest privatized water supply and waste water collection system for the City of Buenos Aires, a city of 9 million people, was faced with the daunting task of providing new service to 1.6 million more people in the first five years of their 30 year concession. Aguas Argentinas elected to use the Negotiated Compressed Process - NCP - for the fast track implementation of a 15000 meter, 3,5 meter diameter tunnel, a key component of the infrastructure master plan. NCP was developed by Klohn Crippen for the $200 million international railway tunnel between Canada and the United States. The conceptual design of the project was performed by Safege Montgomery-Watson, who engaged Klohn Crippento assist with the NCP, the preparation of the tender documents, and implementation of theproject during construction. The process included the purchase by the client Aguas Argentinas of two sophisticated 4 metre diameter earth pressure balance tunnel boring machines from Herrenknecht of Germany. Construction of the tunnel is being performed by the consortium Wayss & Freytag (Germany) and Sollazzo Hnos S.A. (Argentina). The water tunnel is being built with a one pass, bolted segmented gasketed reinforced concrete liner. The purpose of this paper is to describe a transferable methodology for this innovative contracting procedure, the project organization and quality control plan for this important world class tunnel project which is designed to service one of Latin America’s largest metropolitan areas.

Jan 1, 1997

By N. C. Saxena, S. K. Puri, A. K. Pal

The condition-based monitoring system is an important innovation for reducing the downtime of costly, heavy earth- moving machinery (HEMM). Vibration severity measurements were made on the HEMM located at the Gevra Project, the largest coal opencast project in India. Whenever the vibration severity levels exceeded the permissible limits, necessary actions were taken to replace the defective parts of the ma- chine. The systematic vibration monitoring of 120-t (132-st) dumpers, followed by corrective measures led to a substantial increase in component life (8.18% for an 445E Dressor and 28.44% for an MK-30 Unit Rig). The associated costs (including spareparts) were reduced by 21.55% and 25.74%, respectively. Because of the reduced downtime, savings for these two dumpers over the period from March 26 to June 25,1998, were of the order of Rs.26.47 (US$0.649) million.

Jan 1, 2000

By G. C. Presley

Estimated domestic production of pumice and pumicite in 2004 increased about 23 percent since 2003, according to the U. S. Geological Survey (USGS). The USGS estimate of domestic production of 687 kt(757,000 st) for 2003 turned out to be 870 kt (959,000 st)of actual production. The USGS estimated the value of pumice and pumicite sold or used in the United States to be $26 million in 2004, up $4 million from the value in 2003. There was an estimated decrease in the mine, or mill, average price to $24.14/t ($21.90/st) in 2004 from $25.19/t ($22.85/st) in2003.

Jan 1, 2005

By S. M. Pickering, L. T. Gregg

Appraisal of industrial minerals beneath privately owned land requires a different approach and mindset from valuation of base and precious metals or energy minerals, and from valuation of government-owned mineral lands. First, is it the value of inground minerals or of mining rights that is being sought? Second, value to whom, the mining company, a potential investor, the mineral landowner, a lending institution, the property tax assessor, or a condemnor? Third, how should mineral value be apportioned between the land and mineral owner, and a mining company with limited years of lease-hold interest? These and many other questions must be addressed before a valuation method and Discount Rate are selected. For various reasons the Income Method is most often used, with Net Present Value calculations made for long term predicted mining income. Choice of an appropriate Discount Rate is critical.

Jan 1, 2000

By R. W. Smith, D. L. Taylor, K. A. Altman

Recent research has shown that traditional sensitivity, what if and best case/worst case analysis of metallurgical data has the potential to over estimate the value of mining projects. Use of simulations, which rely on the input of statistical information, may provide more realistic predictions of the value of future projects. Actual metallurgical data is used to demonstrate that analyzing the data from a statistical perspective can give insight into completing an optimum amount of metallurgical testing and a mechanism to determine that samples used for the testing are truly representative of the ore that will be processed.

Jan 1, 2000

By G. W. Heunisch

G.A. Carmody and L.B. Anderson We wish to comment on the paper by G.W. Heunisch (MINING ENGINEERING, January 1987), which raised several important points regarding treatment of acidic waste waters. This paper confirms, in part, tests carried out by Allyn Corp. Allyn is the manufacturer of the proprietary product Alka-Ment, one of the materials that Heunisch tested. The first point is the extreme sensitivity of the sedimentation rate on the nature of the treatment material used. This apparently results from differences in nucleation of the metal hydroxides, and is consistently higher for Alka-Ment. This decreased sludge volume is also observed when Alka-Ment is combined with flocculants, such as organic polymers (see Table 1). Our second point is to emphasize that Heunisch&apos;s work shows how dependent the sludge volume is on pH. It is common practice to overtreat AMD by raising pH to 9 or 10. This practice, in addition to being wasteful of material, actually decreases the density of the resulting sludge, probably by creating charged particles that do not readily coalesce. When treating with Alka-Ment, we recommend that the treatment be monitored by testing both pH and dissolved iron. For both tests, it is important to allow adequate time to elapse between treatment and measurement, so that dissolution of alkali, aerobic oxidation of iron, and precipitation of the metal hydroxides are nearly complete. Our tests have indicated that from 30 minutes to one hour is commonly required. Only in this way can a minimum pH be attained, with adequate treatment, denser sludge, and lower treatment rates achieved. Thirdly, Heunisch correctly recognizes that ASTM titration of Alka-Ment does not reflect the true treatment value available in a unit of Alka-Ment. Our work at Allyn indicates this is a most important consideration when evaluating various materials for the treatment of acidic waste waters. While we were unaware of Mr. Heunisch&apos;s work, we welcome comparisons between Alka-Ment and any competitive products readily available for field use. Allyn has hundreds of hours of laboratory and field data we are ready to share with interested parties treating acidic waste water.

Jan 9, 1987

By P. R. Dugan

Sulfur removal from high sulfur coal has several objectives including: a) reduction of the atmospheric load that contributes to the problem of acid precipitation; b) reduction of ash, which contributes to decreased energy transfer in boilers, as well as ash disposal; and c) alleviation of the social and economic dislocations related to uneven geographical distribution of sulfur in coal reserves. Cost in relation to the value of refined coal will govern the development of an emerging coal refining industry. Estimation of the premium paid by power companies for coal with a low sulfur content is a good estimate of the value that will be added as the result of refining. Estimates of premiums paid in 1984 are $28.65/t ($26 per st) for reduction of total sulfur from 370 to 1% S and greater than $28.65/t ($26 per st) for removal below 170 sulfur.

Jan 1, 1988