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By Andrew B. Cecala, Robert J. Timko, Christopher J. Pritchard

As mine venti1ation systems become more complex, it is increasingly difficult to supply fresh air to the working face. A high percentage of the fresh air entering a mine never reaches the working face because it short circuits through stoppings and doors, exiting the mine without being utilized. When ventilation limits are reached, the only option presently available to most U.S. mines is to sink a new shaft - an extremely expensive undertaking that many companies cannot afford. Reusing or recirculating a percentage of ventilating airflow may make it possible for some mines to remain operational while maintaining a safe environment for workers. Such a study was performed at a trona mine in Granger. Wyoming. A vane axial fan was used to recirculate approximately 9.4 m /s (20,000 cfm), 25% of the total ventilating airflow, back to the working face area of a three-entry continuous miner section. This study involved two evaluations: the first when the face was 305m (1,000 ft) from the recirculation fan, the second when the face was 610m (2,000 ft) from the fan. The evaluation consisted of monitoring the mine atmosphere for respirable dust, methane (CH4). carbon monoxide (CO), and nitric oxide (NO), at various locations in the intake and return entries. Several shifts were monitored, with and without the recirculation system in operation. With the recirculation system in operation. there was an increase in measured respirable dust concentrations in the intake along with a slight increase in the mine temperature (1.67°C). There were also some minor changes in CO and NO levels in the intake entry, but this seemed to depend on the proximity of the instruments to the turn-around point for the diesel haulage vehicles, than to whether the recirculation system was or was not in use.

Jan 1, 1989

By Arland R. Krueger

You have asked me today to tell you how quarried stone is meeting the challenges of contemporary architecture. The new position of stone, the oldest building material, in contemporary architecture, was described to me very concisely the other day by a very distinguished avant garde architect. He said rather wryly, "Do you know, if quarried stone had only just been discovered, we would all be calling it the most miraculous of all the modern miracle building materials." His prognosis was, I believe, much more than a witty quote. It echoes the surprise and. enthusiasm with which a considerable segment of the architectural profession is rediscovering stone as a most modern building material that offers unsurpassed values in beauty and practicality - well deserving of the term "miracle".

Jan 1, 1960

By Frank W. Reinrniller

Mill ball charging systems have undergone little change during the past two decades. Most operations utilize a locomotive/ball car combination to load and haul charges from the ball storage bin to the mill charging boxes or, alternatively, transport charges to the charging boxes by means of a ball bucket handled by bridge crane. This paper describes a new concept in ball handling systems that is in operation at the Island Copper Concentrator of Utah Mines, Ltd. at Port Hardy, B.C. This system employs a narrow belt conveyor to convey a weighed charge to each of nine belt unloading stations at the mills. In operation, the system has proved to be practicable, trouble-free and economical of operating labor.

Jan 1, 1977

By I. Yaniv

The magneto-hydrostatic method can be used today to separate slightly magnetic or non-magnetic particles according to differences in their specific gravities and magnetic susceptibilities. The classical approach is to effect stratification prior to separation. This paper discusses some of the significant parameters which bear on the design and pattern of the expected stratification in the separation cell. As the characteristics of the magnetic field, and consequently those of the magnetic forces, are determined by the geometry of the poles, this subject is treated first. In this context a new approach, whereby the range of stratification is extended, using positive as well as negative gradients, is presented. Finally, the effect of the relative size and shape of the particles on stratification is discussed.

Jan 1, 1978

By Frank W. Bowdish

Studies of sulfidization and flotation of chrysocolla involving the use of pH and sulfide ion instruments, a Zeta meter, microflotation techniques, and sensitive determinations of adsorbed sulfur have given new insight into the mechanism of the process. Factors that affect the recovery of sulfidized chrysocolla by flotation appear to be the pH at which it is sulfidized, and certain alterations of the surface that occur during aging after sulfidization. Such aging results in increased recoveries. The surface charge, as measured by electrophoretic mobility, of chrysocolla shows an unexpected negative increase as pH values are changed from 6.0 to about 4.5, and this appears to be correlated with increasing sulfur adsorption and flotation recovery over the same or even wider pH ranges.

Jan 1, 1970

Two years ago, about the only US mining ventures that could turn even marginal profits were precious metals. In 1986, the price of gold dramatically increased, as did earnings from precious metals, mostly gold mines. First quarter results for 1987 show that gold will again be the most profitable type of mining in the US. All this money being made in gold resulted in many new mines being opened and hundreds of old workings being re-evaluated. The Society of Mining Engineers has put together a technical program to aid in developing precious metals mines. Small Mines Development in Precious Metals will take place Aug. 30-Sept. 2, 1987 at Bally's Hotel, Reno, NV. For registration and hotel information see page 426 or contact Meetings Department, SME, P.O. Box 625002, Littleton, CO 80162-5002, 303-973-9550. Topics at this meeting will include Problems Facing Small Miners; Understanding Geology and Ore Reserves; Mining-Production Options to Maintain Competitiveness; Processing for Precious Metals; Financing and Economics that Work for Small Miners; and Understanding the Environmental and Permit Maze. Problems facing the small miner The small miner has found and started most of the productive mines in the world, says Alfred G. Hoyl, of Coal Fuels Corp., Rollinsville, CO. Hoyl will state his case for small mines development in the opening session of the program. He will make the point that government regulations must never restrict the small mine or miner. And the mining industry must be careful not to crowd out the independent miner. "To restrict small mining is to say to our young men and women entering the mineral industry `There is no place for you as an independent.' Small is a relative term and we must never feel that starting small will restrict our possibilities of becoming big." In the same session, David J. Starbuck, Starbuck Minerals Management, Mayer, AZ will take a look at why smaller precious metals mines are profitable. Mining companies have changed their perspective on reworking previously mined properties. They are looking at abandoned properties in older mining districts. The attitude is that smaller operations in these districts can be profitable with the present economic climate, more advanced technology, and better management. Small, independent mining companies may not have the same resources to draw from as the majors. But there are affordable technologies available that fit into the independents' budget. Betty Gibbs, of Gibbs Associates, Boulder, Co will explain how a personal computer can help a small operation to analyze data more effectively and respond quickly to changing conditions. Scenarios will be developed that will describe how PCs can be incorporated into all phases of an operation. Financial institutions are becoming more willing to consider venture capital for small precious metals mines, according to Stanley Dempsey, Denver Mining Finance Co., Denver, CO. This may be in the form of equity or debt, he says, but they want to receive assurances of the quality of the resource. And they will ask about the ore reserves. Next, the potential lender will want to know about the mining method and en¬vironmental regulations. Dempsey will discuss these requirements. Once a high grade gold mineralization is located and reserves proven, it must be evaluated to determine which recovery process is best suited for this deposit. Robert Martinez, Amselco Minerals, Ely, NV will evaluate processes for such a deposit located in Mexico. Heap leaching, vat leaching, and a carbon-in-pulp circuit are all viable options, he says. He will explain which recovery process proved to be the most economic. Other papers in the introductory session include How to Best Use Consulting Firms to Accelerate the Development Process, by H. Schreiber and R.P. Fronk, both of Behre Dolbear-Riverside, New York, NY. And W. Mayrsohn of Asamera Minerals, Denver, CO will present Marketing Fundamentals that Work for Small Mines. Understanding geology and ore reserves In the current scheme of fast-track exploration and mine development, insufficient time and thought is given to understanding the geology of a deposit as it relates to controls of mineralization and subsequent mine development, say D.S. Bolin and J.W. Rozelle, of Pincock, Allen & Holt,

Jan 6, 1987

By R. Bleischwitz, R. Delzeit

"Tantalum, a heavy metal with characteristics such as superconductivity and high terminal resistance, nowadays is the most efficient material for production of capacitors, which are essential for production of small electronic applications like notebooks and cell-phones. It is one of the strategic resources for information societies. With supply extracted from Central Africa (Congo / DRC), China, Australia, and Canada, it can serve as an example for sustainability efforts in the management of non-renewable resources in Developing Countries, Newly Industrializing Countries and Industrialized Countries alike. The paper analyzes the life cycle of tantalum in its environmental, social, and economic dimensions. The first section highlights the importance of tantalum, showing a demand-driven market. The second section analyzes current and future supply. The third section tackles environmental and social impacts of tantalum mining in different legislations. The fourth section especially deals with the Case of the Democratic Republic of Congo since companies have been accused of participating in a civil ‘resource war’. Section five will draw conclusions for sustainable resource management. Written in an interdisciplinary manner, the article has a bearing on economics, especially on resource economics and new institutional economics, as well as on geography. It deals with questions such as security implications of physical scarcity in rapidly growing markets. In doing so it can, firstly, be shown that information exchange in combination with reputational risks lead to a shift in extraction activities from a Developing Country (DRC) to an Industrialized Country (Australia); i.e. a ‘race to the bottom’ does not take place. This, however, does not mean that market mechanisms work properly since information exchange (especially with China) is incomplete, moral hazard still prevails, and inadequate institutions hamper development processes in an exporting country like Congo. Any sustainable resource management for tantalum not only should foster gathering and exchanging better information on environmental and social impacts, but also incentives for upstream metal recycling in industry as well as support for governance processes in Developing Countries"

Jan 1, 2005

By George Munro

Heavy water inflows of up to 1350 1/sec in the 19.6 km Moawhango-Tongariro Tunnel section of the Tongariro Power Development Scheme in New Zealand gave rise to severe operating problems, particularly in the equipment stripping stage when pumping installations had to be removed. Due to the necessity to commence stripping from the upstream side the contractors. Codelfa-Cogefar (NZ) Limited, took the decision to install a steel bulkhead some 5000m in from the lower. Tongariro, portal. The article lists the considerations taken in the placement of the bulkhead, and gives details of its design, installation and final removal. A brief description of the geology of the tunnel. together with water flow sources, rates and pressures is also included.

Jan 1, 1981

By Craig J. Nelsen, David A. Smith

In 1987, LAC Minerals (USA), Inc. conducted a high resolution helicopter electromagnetic (EM) and magnetic geophysical survey on the Ortiz Mine Grant, New Mexico. The primary purpose of this survey was to assist in geologic mapping of a major structural zone, the Tijeras-Canoncito Fault System (TCFS). This structure is a very important ore- controlling feature in the area. Geophysical signatures over known deposits was a secondary goal of the survey, but direct detection of mineralization was not anticipated. The TCFS was revealed to be a complex, branching and anastomosing system of faults which locally form the bounding structures of a graben. The geophysical survey guided subsequent geologic mapping by redirecting field investigations, and geophysically redefining some features which previously had been only partly defined.

Jan 1, 1989

By Dick Lewis

The Misima deposit is on Misima Island in the Lousaide Archipelago, 240 km east-southeast of the Papua New Guinea mainland, and 600 km east of Port Morseby. Misima is a narrow mountainous island 40 km long and up to 10 km wide. The highest point is 1035 m above sea level. Gold mineralization is restricted to the eastern and less rugged third of the island. The Melanesian population lives in coastal villages. Subsistence agriculture is the main activity, although copra and cocoa are grown in plantations on the eastern and southern coasts. Prior to 1950, mining was important in the economy of the island. Climate is tropical, with little seasonal variation in temperature or rainfall. Tropical cyclones occur about every 10 years (Fig. 1).

Jan 1, 1990

By P .. F. Ziemkiewicz, T. E. Rymer, J. J. Renton

Prediction and quantification of acid mine drainage (AMD) from a given rock unit is in its infancy. Acid Base Accounting is the current procedure. II is a useful screening procedure and is designed to indicate whether a rock unit will or will not produce acid. In this sense, Acid Base Accounting is qualiwtivc. Researchers at West Virginia University arc developing a prediction method to estimate how much acid will be produced over the life of a rock unit's AMD production. TI1c AMD prediction procedure can also evaluate the required rates and effectiveness of various AMD control amendments. This presentation discusses the WVU AMD prediction procedure in the context of historical approaches and indicates the mechanics and applications of this new technology.

Jan 1, 1991

By Taira Emoto, Hikozou Imaoka, Sohta Takatsu, Takeshi Suzuki, Yoshihito Minami

An Oval Section TBM (tunnel boring machine) enables excavation of tunnel with elliptical cross section by inclining the cutterhead. It is developed to utilize the proven conventional TBM technology with minimum modifications. Various types of tunnels which are preferred to have non-circular cross section can be economically excavated, reducing both overbreak and the amount of muck produced. On the other hand, an inclined cutterhead may create a number of new problems, such as in excavation efficiency and steering that are unknown in excavation works using a circular TBM. This paper reports on verification tests carried out to examine the extent of such problems using experimental models of the machine in an attempt to confirm the feasibility of the Oval Section TBM.

Jan 1, 1997

By Hélio Blak

The Paranapanema Group was created in February 1996 when a group formed by the Brazilian pension funds acquired four companies dealing with nonferrous metals. The new Paranapanema Group, basically related to the tin and construction business, became the sole Brazilian primary copper producer, the second zinc producer and one of the most important producers of copper products, mainly tubes and fittings. To put together such different companies, managed before by family groups and with different cultures and principles, was and still is a big challenge. The strategy of developing and consolidating it as an homogeneous group is based in three pillars: an increase in production, quality and technological improvements on products and market mix and a permanent cost reduction program, using all the potential synergies founded.

Jan 1, 1998

By Chinmoy Sarkar

Mining organizations have been trying to employ best practices at exploration, exploitation and processing level to increase productivity in the supply chain. Traditional techniques of cost control can no longer meet the ambitious target of mine managers. An integrated perspective of Mining Value Chain with enterprise-wide application of information technology (IT) ensures the ability of every mining processes to improve energy, land, capital and labour resource performance while continuing to cut costs and achieve profitability. IT offers enormous potential in mining industry at shaping entirely new opportunities to create value. This paper characterizes important entities of Mining Value Chain and attempts to provide a vision on how IT can transform the mindsets of industry managers addressing the needs of the customers.

Jan 1, 2002

By Marco D. Boscardin

During subsidence, the ground surface may settle, change slope, change curvature, go into tension, and/or go into compression. In response to these ground movements, buildings and buried utilities in the subsidence area may settle, tilt, bend, distort, and sustain extension, compression and/or torsion. In order to develop measures to protect existing structures and utilities, or to design new structures and utilities to withstand potential movements in areas of subsidence, it is necessary to understand the interaction between the ground and the building or buried the utility. This paper reviews subsidence-induced ground movements, how these ground movements are transmitted to and accommodated by buildings and buried pipelines, and how these structures may alter ground movements relative to free field subsidence-induced ground movements.

Jan 1, 1986

By J. R. Parry

Over the past several years, computerized financial models have been an important part of Newmont's strategic planning process. Two applications will be discussed in this paper: a general purpose financial model of Newmont, and a detailed operational/financial model of Magma Copper Company. Newmont?s general purpose financial model was developed using Lotus 1-2-3. It was designed to aid management in assessing the financial consequences of investment and financing decisions associated with long-term strategic planning by simulating the consolidated effect from individual transactions. Not only is the model capable of assessing the sensitivity of specific decisions to changes in the external economic environment (i. e., commodity prices, interest rates, inflation and exchange rates), it can also evaluate the effect from operating and financial decisions, including changing production levels and cost structures at individual operating units as well as simulating several types of transactions, including equity and debt issues, acquisitions and divestitures. The analysis of Magma Copper Company required the development of a detailed operating and financial model of the Company. The model was developed using IFPS in the corporation?s UNISYS (then Burroughs) B7900 mainframe computer and included separate pro forma financial statements for each of San Manuel-Pinto Valley's mines and concentrators, as well as Magma's smelting and refining operations. The outcome of this analysis was the decision to merge Magma Copper and Pinto Valley Copper Corporation, and to recapitalize the new corporation in order to provide funds for a retrofit and expansion of its Arizona smelter and expansions of its refinery and SXEW facilities.

Jan 1, 1989

By S. K. Mishra

Introduction The history of the Australian coal industry is almost as old as the history of Australia after new settlement. The first cargo of coal was exported from Newcastle to India in 1799. Coal has been mined in Australia for almost two centuries. But there are indications that the first coal was processed in 1877 in the Newcastle area. This is nearly 50 years after the first coal processing in Europe. Processing on any significant scale began in 1944 at the Newcastle Steel Works. In Queensland, however, coal processing did not begin until the second quarter of this century. The dramatic growth of mining and processing of Australian coal since the mid-60s is primarily due to the expansion of the export market in Japan, Asia, and Europe. Australian coals Black coal occurs in most of the major sedimentary basins of Australia. The better known deposits of commercial importance are in the Sydney, Bowen, Oakland, and Gailiee Basins. Apart from the Collie Basin in western Australia, other coal deposits of the Arckinga Basin in South Australia, the Bonaparte Basin in Northern Territory, and the Tasmania Basin are basically unexploited. The Sydney Basin of New South Wales and Bowen Basin of Queensland remain the major producers of black coal in Australia. Currently exploited or potentially commercial deposits of black coal in Australia occur in strata ranging in age from Permian to Tertiary. Estimated black coal reserves are summarized in Table 1. Coals from different ages have significant differences in their petrographic characteristics. Many of the Permian coals are usually rich in inertinite. Jurassic and Tertiary coals are typically rich in vitrinite content. Typical petrographic and chemical characteristics of some important Australian coking coals are summarized in Tables 2 and 3. The reserves of coking coals are restricted in the main to the Permian coals of the Sydney and Bowen Basins. Coal deposits in the latter are at shallow depth. A high percentage of these are being strip-mined. On the other hand, in the Sydney Basin, the majority of the reserves of good quality coking coals are at significant depth. The mining cost of these deposits is substantially higher than those in the Bowen Basin. It is usually possible to make strong coke with Australian Permian coals of vitrinite content much lower than the other international coals. But there are many major Permian deposits in Australia where low vitrinite content presents problems. As they are classified as marginal coking coals, optimization of their pro¬cessing plays an important role in meeting the market specifications of coking coal. The major reason for processing Australian coal is to reduce the ash content. Compared with British and some American coals, Australian coals are of relatively high ash content. Unlike American coals, more than 99% of the Australian coal deposits have sulfur content less than 1%. Consequently, sulfur control has never been a major problem. The coking quality of coal is improved simply through the ash reduction in the marketable product. However, with the increase in intensive mechanization and multi-stage handling of coal be-

Jan 9, 1985

By George J. Simchuk

The selection of a stripping method and subsequently, the stripping equipment, are two of the most important decisions confronting a project engineering staff during the initial feasibility study of a new coal stripping operation. The selected stripping units average from 60 to 70 percent of the total capital outlay for mine equipment and their selection will affect the type, size, and quantity of the attendant equipment, such as loading shovels, drills, haulage trucks, and bulldozers. This paper is intended to report on an in depth study by Utah's Technical Services Staff regarding the selection of stripping equipment for the Goonyella Coal Mine in Queensland, Australia. We will touch briefly, on the objectives considered in this selection; the various alternatives which were explored; the general assumptions that were followed throughout the engineering and design of an appropriate stripping system; and computations necessary to determine the amount and size of stripping equipment. INITIAL EXPLORATION Utah Development Company (presently 90% owned by Utah Construction & Mining Co. and 10% by Australian investors) commenced systematic geological studies of the Bowen Basin coal fields of Central Queensland in 1961. The Blackwater Mine as shown in Figure 1 has since been established in this area and is now producing 3.0 million tons per annum of washed coking coal. Geological reconnaissance was then extended to the northern part of the Bowen Basin and in 1963 Utah's coal prospecting area covered 2444 square miles of Central Queensland. The authority to prospect north of Blackwater has since been trimmed to 810 square miles by relinquishments to the State.

Jan 1, 1971

By C. Braux

The aim of this study was to develop an integrated approach to enable identification of areas favourable for the presence of massive sulphide deposits in a given region (Las Herrerias, Spain). It is based on geochemical soil exploration, geophysical surveying (ground gravimetry), detailed geological mapping and a knowledge of the deposits of the South Iberian Massive Sulphide Belt. The multi-dataset approach consists, in the first instance, in standardizing and combining all the geochemical data with reference to their geological setting. Next, the "heavy" anomalies are extracted from the gravimetric survey, regardless of the surrounding context (heavy or light). The results from these two stages are then crossed, so that areas where heavy anomalies are associated with geochemical anomalies can be identified and classified. Crossing the geochemical and geophysical data enables a much tighter selection of anomalies than does the manual superposition of data provided by each method (geology, geophysics, geochemistry).

Jan 1, 1994

By P. Anciaux

The EUs? manufacturing and construction industries are vital to Europe?s economy. They rely heavily on a steady supply of materials which meet appropriate quality criteria and are available at a competitive price. The steadily rising global demand for (non-energy) raw materials due to increasing consumption in upcoming economies such as China, India and Brazil, is in some cases leading to rapid price increases, but also supply disruptions which affect the European industry chain. These considerations are at the basis of new policy initiatives that are being prepared by Enterprise and Industry Directorate-General in relation to the competitiveness of the European metals industry. Over the last year the raw materials supply issue has increasingly become the topic of de-bate among various stakeholders. In July 2006 the European Economic and Social Committee adopted an opinion on risks and problems associated with the supply of raw materials to European industry. It is therefore important to identify and analyse the future needs for European industry, the possible constraints and impacts on its competitiveness. The raw materials supply issue should also be looked at from the view-point of the EU extractive industry, which plays an important role in supplying raw materials to the downstream industries and which faces very specific challenges. Within the Enterprise and Industry Directorate-General the different factors that influence the competitiveness of the non-energy extractive industry are being assessed, in order to help identify policies and actions which could contribute to and enhance the competitiveness of the industry.

Jan 1, 2007