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By G. J. Koons, J. L. Uhrie

Field density studies carried out at the Phelps Dodge Chino Mine have found that truck-induced compaction is limited to the upper 2.4 meters (8 feet) of an individual lift. Hydraulic properties of material compacted to field densities were determined in a laboratory setting and saturated flow models were then run, simulating the effect of compacted zones within a stockpile. Modeling shows that compaction can effectively prevent solution flow through large portions of the stockpile, implying that great care must be taken to ensure that ripping is carried out to a full depth of at least 2.4 meters (8 feet) across the entire stockpile to achieve uniform solution flow. Uniform solution flow will result in maximum leach recovery.

Jan 1, 2000

By R. D. Sharpe

Gypsum wallboard manufacturers in the United States shipped 3.18 billion m2 (34.2 billion sq ft) of wall-board products during 2004 versus 2.93 billion m2 (31.5billion sq ft) in 2003. Following a historic high production of gypsum wallboard products in 1999, production decreased in 2000. But it has steadily increased during2001 through 2004. Wallboard production in the United States increased about 8.6 percent in 2004 from 2003. Following several years of a “building boom” of new wallboard plants and the expansion of the manufacturing capacity of several existing plants, 2004 was a relatively quiet year. However, several new plants and capacity expansions were announced or are in progress during 2004.

Jan 1, 2005

By Raúl Castro, Marco Vera, Alfonso Ovalle

The underground mining evolution for block cave mines in Chile and worldwide has made important strides in the last decades. Nonetheless, reserves determination in the initial stages of these types of projects—mainly for long-term planning—is not studied in as much detail as it should be, especially regarding the impact on the final value of the enterprise. Today, the first estimation of the size of a block cave mine, typically expressed in tons, tends to determine very large footprints and ore bodies. The resulting large-scale mine is obtained by applying the marginal cut-off grade (COG) to determine reserves. Yet, in many cases, it is possible to obtain an equal or higher benefit, extracting fewer reserves in less time, with a smaller active area, which significantly reduces the project’s uncertainty. To explore scenarios obtained by applying a higher marginal COG in the initial phases of the project, the Hill of Value methodology is used to estimate the net present value (NPV) in relation to the production rate and the COG. However, the application of this methodology considers certain simplifications that generate results which are not completely satisfactory in specific cases. This paper suggests an improvement of this method to obtain more reliable results regarding determination of a COG profile that will optimize the NPVof a block-cave project. The methodology was developed and applied in a massive polymetallic deposit with zinc, lead, and silver mineralization, corresponding to a real block caving project. The methodology provides NPV results that differ by approximately 15% in comparison to the real mine plan, while also being considerably simpler and faster to calculate. In summary, the proposed methodology provides a reasonable and fast procedure to estimate higher than marginal COG that increases the NPV of block cave mine projects.

By John J. Simmons

Federal and state regulations, in an effort to reduce acid rain, are becoming increasing more stringent regarding sulfur content of fossil fuels. Whereas coal from Illinois and Ohio contains between 1.5 and 37. sulfur, Wyoming has billions of tons of coal reserves containing less than O.5/% sulfur. However, much of Wyoming's coal is high in moisture, 25-30%, and low in energy, 8,200 to 8,900 BTU, vs. 10,500+ BTU for Illinois and Ohio Basin coals. Wyoming currently ships in excess of 130 million tons of coal to utilities as distant as Michigan, Wisconsin, Minnesota, Iowa, Nebraska, Louisiana, Oklahoma, and Texas. With freight charges ranging from $12.00-$20.00/ton, more than $1.5 billion a year is spent to transport water. A test shipment of more than 50,000 tons of Wyoming coal has recently been made from Mobil's Cabello Rojo Mine, south of Gillette, by Burlington Northern to the Robert's Bank British Columbia coal terminal for transloading and shipment to Taiwan Power Company. This coal assayed approximately 8,400 BTU/lb. and 277. moisture. Carbontec Energy Corporation feels the future availability of dried coal containing 11,000+ BTU could substantially enhance the potential export as well as the domestic market for Wyoming coal. Large and small utilities, along with industrial furnaces require tens of millions of tons of Wyoming, West Virginia, and other Eastern The federal government is encouraging the expenditure of hundreds of million of dollars by utilities to retrofit their boilers to allow them to burn higher sulfur coal. This program, if carried to completion, would cost many tens of billions of dollars, with the net result being high power costs sustained by the utilities. These costs will be passed on and paid for by the American consumer. A sensible alternative would be the burning of low sulfur coal by the utilities, without costly capital and operating expenditures. Carbontec Energy feels the successful operation of a Carbondry Coal Drying Plant in Wyoming will be the forerunner to other similar and larger operations in the State. CARBONTEC RESEARCH The activities of Carbontec's personnel to develop a viable process to dry sub-bituminous and lignite coal goes back some 14 years; in fact, for some of us it goes back to 1962 when we were involved in a program under which lignite coal from Truax Trayer's Velva mine was placed in low sulfur coal, which are burned alone or blended with high sulfur, Midwestern coal. Carbontec believes that a high BTU. reasonably priced, shippable coal fuel produced in Wyoming and delivered at costs competitive with Eastern low sulfur coal, could offer substantial benefits to Wyoming coal producers, utility customers, and to the State of Wyoming.

Jan 1, 1989

By N. Powell, C. F. Spollen, B. A. Wills

A discussion of the practicalities of carrying out a material balance using simple nodal sensitivity analysis is given. The calculation of the errors involved is reviewed and the concept of co-variance examined through computer simulation. The use of co-variances in such calculations is shown to be practically insignificant. The method proves to be rapid and relatively accurate provided the circuit topology is correct.

Jan 1, 1991

By Steve Kral

The Northwest Mining Association (NWMA) has been an advocate for the U.S. mining industry since 1895. For several decades, the organization has represented mining members located mostly in the Northwest and some southwestern Canadian provinces. Today, though, the NWMA?s membership is located in 42 states and seven provinces and has become a national voice for the mining industry. So, during the association?s 119th and final meeting as the NWMA, a name change was announced. The organization is now called the American Exploration and Mining Association (AEMA). But that?s not all that has changed, according to the association. The new name reflects more closely the diversity and location of the AEMA?s membership. It will still be an advocate for the mining industry, dealing with land, environmental and community issues on state and federal levels. The conference, held in December 2013 in Reno, NV, attracted about 2,500 attendees. And the accompanying exhibit included 230 equipment and service suppliers in 246 booths. Technical programming ran the gamut of mining industry issues and technologies, including surface and underground mining; high technology systems and automation in mining, metallurgy and exploration; along with social issues, finance and safety. The following is a sample of some of the sessions.

Mar 1, 2014

The mining and minerals extraction industries have often been demonized by the public as industries that put profits and production before people. It is true that the inherent danger of the work has led to more fatal accidents than anyone associated with the industry would care to remember. But, in stark contrast to what has often been said, the truth of the matter is safety is now the top priority of every miner, from the face of the longwall to the executive boardroom. Without safety, nothing else matters. This message was told and retold by representatives from some of the world?s top mining and petroleum companies from Oct. 11-13 during the inaugural Safety and Reliability in the Mining and Resources Industries Conference in Calgary, Canada. The meeting was hosted jointly by the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) and the Society for Mining, Metallurgy, and Exploration (SME). It was the first of a series of conferences to focus on these important topics. Next year, the conference will be held in Minneapolis, MN from Nov. 13-15.

Jan 1, 2011

By Robin P. Gardner

The mechanistic approach to comminution consisting of incorporating particulate breakage functions into a suitable population balance equation has been developed by a number of researchers over the past decade or so. (1) To date this approach has been developed and demonstrated primarily for batch-operated, laboratory or small-scale ball mills. However, since industrial mills are mostly quite large and operated in the continuous mode; suitable population balance models and methods for obtaining the necessary breakage and other model parameters must be developed. This paper describes and investigates a radioisotope tracer technique for this purpose, Population balance models previously developed(2,3) are adapted for this study.

Jan 1, 1974

By Paul C. Schmall

In recent years, several geotechnical methods have been successfully applied to ash pond closure. These include modified dewatering techniques with wellpoints and wells to physically drain the material, soil mixing to create a soil-concrete material for improved accessways as well as improved ground structures within ponds to act as barriers or gravity dams, and geotechnical instrumentation to serve as an early warning of the potential for liquefaction. Given the parallels between fly ash and sluiced in place mine tailings, the application of fly ash remediation method to mine tailings shows significant potential, as illustrated in this paper.

Feb 1, 2024

By Jackson G. Jenkins

Magma Copper Company's San Manuel SX-EW facility has operated since May, 1986. The original facility had a design capacity of 25,000 tons per year of electrowon copper cathode produced by processing pregnant leach solution from an open pit/heap leach operation. In 1988, the plant was expanded to 50,000 tons per year to incorporate processing in-situ leach solutions. This paper focuses primarily on the heap leaching area with regard to exploration, testing, feasibility, permitting, design and construction, and operating practices. Research utilizing surfactant leaching aids to enhance copper recovery is also discussed.

Jan 1, 1993

By John J. Dran

In recent years, market rates of interest have risen well above their historical long-term average. Also during this period, the short-term variability of interest rates has been greater than in prior years. Interest rates have a significant effect on the operation of our economy. They influence the extractive industries in a number of ways. Their major long- range impact is on investment decisions - specifically the valuation of mineral deposits. An understanding of the factors that influence interest rates is important to the engineer or businessman who makes the investment decisions for the mining company. The effect of changes in the market rate of interest on the value of mineral reserves is critical to the future financial success of the mining enterprise. The most common simplification of the factors determining the level of interest rates is that they are a function of the demand for and the supply of money. While this is an oversimplification, most businessmen would be hard- pressed to provide a better explanation. The purpose of this paper is to explore certain fundamental economic aspects of interest rates and to examine their effect on the analysis of investment in mineral deposits.

Jan 1, 1975

By Lester G. Rollins

Coal today enjoys a dominant position, serving the energy and metallurgical marketed The measure of success in the market place is, and will continue to be, the price per million BTUs or price per ton delivered to the user. The Coal Industry's remarkable record of price stability since World War II is well known. The next twenty years promise to be equally as challenging. This challenge will be met our president, Mr. Drain, has often stated that, ?The Joy Manufacturing Company is betting that coal will meet the challenge.? To this end, the resources of Joy have been committed to doing its part. Joy's efforts are directed toward a target which has been defined as: 1. Deliver coal to the user at a price of $.15/MBTU or less. or; 2. Deliver coal to the mine portal at a cost of $1.00 or less.

Jan 1, 1966

By H. H. Murray

Recently developed clay deposits that will impact regional and world markets are described. These deposits, their location, geology, and physical properties are delineated. Kaolins from the State of Para in Brazil and from Ukraine; bentonites from Argentina and India; and palygorskite and sepiolite from China are world class deposits that when processed using modem technology will produce excellent products. Other deposits that may affect regional markets are kaolins from China, Australia and Indonesia; bentonites from Georgia (formerly USSR) and China; and palygorskite from India and Ukraine. New ball clay deposits that will affect regional markets are in China and Indonesia.

Jan 1, 1999

By Massimo Concilia, Remo Grandori, Paolo Nardone

Paul Y. – SELI Joint Venture had been contracted to build the longest section of the Strategic Sewage Disposal Scheme (SSDS) – Stage I. This involved two tunnels under urban and marine areas excavated by high performance hard rock open type TBMs operated from deep shafts. A specific ground treatment program was developed using advance probing and grouting to control water inflow into the excavations. The article describes: the technologies adopted, the experienced problems, the encountered productions and their interrelation with the water inflow amounts, the possible improvement in the technologies for the excavation of the future stages of the same project as well of any other project under similar conditions.

Jan 1, 2001

By James J. Fallon

I'm glad this meeting is being held in New York. First, because the city is close to my home in New Jersey, only 35 minutes from Times Square ..... if I were to come to Times Square between two and three in the morning. Otherwise it takes two hours. But even more important is the fact that all of you good people from around the country and around the world will enjoy the unique experience of that warm friendly atmosphere in the greater metropolitan area, something that you won't see any place else on the face of the earth. Seriously, the greater metropolitan area has been a large part of my industrial, cultural and spiritual experience. There are many aspects of it which I find disagreeable but on net I would rather live in this area, at least for the time being, than any other area of the United States. As a consultant I find contact with financial institutions, corporate headquarters, information sources and a great many production and research facilities a valuable asset to my activity.

Jan 1, 1985

By Scott Burchmore, Jason Emery, Michael Melville

This paper presents best practice data management for monitoring of extensometers in Australian underground coal mines. This work is based on the combined experience of the authors and the available literature. The information and ideas presented herein are a culmination of many years of database development founded from mine site-based ground support design, underground inspections, extensometer data management and data analysis. Each author has more than ten years’ experience as a practicing geotechnical engineer at several operating industry wide research project focused on utilizing mechanical extensometer data for data analytics and machine learning. Principal hazard ground control management plans, stipulated in Australian coal mining legislation, outline the mandatory installation of ground monitoring devices during routine mining activities. After 20+ years of data gathering the barrier to implementing modern data analytics remains the challenges imposed by inconsistent data structure and data quality. This inconsistency is still routinely found between sites, companies and mining regions. Through the relatively simple application of a standardized database structure, the potential to shift from simplistic tracking of trigger levels, siloed at individual sites, to an industry standard method for compilation & comparison of monitoring data is enabled.

Jun 25, 2024

By Kenneth S. Johnson

Iodine, a grayish-black nonmetallic element, with a density of 4.9 g/cm3, is a solid at ordinary temperatures. It is a member of the halogen family, along with fluorine, chlorine, bromine, and astatine. Iodine melts at 114°C. and at 184°C it is volatilized to a blue-violet gas that has an irritating odor. It does not occur as an element in nature, but occurs as iodates, iodides, or other combined forms. It is the 47th most abundant element in the earth's crust. Iodine was discovered by Bernard Courtois in 1811. He observed an unknown substance in the crude soda ash that results from the burning of seaweed. Samples of this unknown substance were identified to be a new element, and in 1813 Gay-Lussac named the substance iode, from the Greek word for violet color. The world production during 1989 and 1990 [(Table 1)] is estimated to be about 16 million kg per year (Lyday, 1991), of which about 30% is consumed in the United States. GEOLOGY AND MINERALOGY Compounds of iodine are minor constituents in seawater and brines, in certain marine organisms, and in minerals of the Chilean nitrate deposits. Seawater contains approximately 0.05 ppm iodine, and certain marine organisms, such as seaweed, sponges, fish, and some brown algae, are able to further concentrate iodine (Lyday, 1989a). Some seaweed can extract and accumulate iodine up to 0.45% of their weight, on a dry basis. The northern Chilean nitrate deposits, in the Atacama Desert, contain the following iodine minerals: lautarite, Ca(I03), (calcium iodate); dietzeite, CaJIO,), (CrO,) (calcium iodate-chromate); and bruggenite, Ca(I03), . H20 (Erickson, 1981). Various subsurface brines also contain iodine compounds. Some gas-field brines in the United States and Japan locally contain 30 to 1 300 ppm iodine. Several coals in Germany also contain iodine compounds. Iodine has been recovered from brines mainly in Japan and the United States, but also in Java, Indonesia, Italy, England, and the former USSR. Iodine has also been recovered from seaweed in Ireland, Scotland, France, Japan, Norway, and the USSR. Seaweed was a major source of iodine for the world in the first half of this century, and it remains as a large resource. The reserves and future resources of iodine are large, even excluding the resources in seaweed and seawater, and are shown in [Table 1]. Analysis Iodine as the free element can be detected by the characteristic blue color it gives to a starch solution. Quantitatively it is determined as the free element by titration with standard thiosulfate solutions using starch as an indicator. Colorimetric methods are also applicable. PRINCIPAL PRODUCING COUNTRIES Major iodine-producing nations are Japan, Chile, the USSR, and the United States, with lesser amounts being produced in China and Indonesia ([Fig. 1; Table 1]). Annual world production in 1989 and 1990, respectively, is estimated at 15.6 and 16 million kg. In Japan and Chile, the production of iodine depends on production of other materials, such as natural gas or nitrates, respectively, whereas in US operations (in Oklahoma) iodine is the major product recovered from natural brines. Chile was for a long time the principal world producer of iodine from its nitrate-fertilizer operations, but in recent years Japan has become the world leader with increased production of natural gas and associated iodine-rich brines.

Jan 1, 1994

By T. R. Ellis

Australia’s mineral valuation code continues to evolve, while mineral valuation standards are also being written for Canada and Southern Africa. The author is leading a task force for writing the extractive industries addition to the International Valuation Standards. Meanwhile, the International Accounting Standards Board is continuing the development of an extractive industries addition to its International Financial Reporting Standards, with an emphasis on valuation reporting. This paper analyzes the need, content and ownership for a U.S. minerals appraisal standard in the context of both these developing international standards and also existing U.S. regulations and appraisal standards. The author provides many questions for research and debate.

Jan 1, 2003

By C. Patrick

Longwall face-to-face equipment transfers or moves are, for many companies, the largest single source of non-productive time in a longwall mining system. Detailed planning and resourceful thinking are paramount for economical, safe, and timely longwall moves. New equipment and innovative techniques are frequently tested in order to reduce overall move time. Determining the cost effectiveness of these ideas is difficult since the decision is influenced by many subjective factors. A project scheduling simulation model of the longwall move process was developed in order to analyze and assess the economic viability of innovative transfer methods and equipment. The model provides a project duration frequency distribution and lists of critically indexed activities and paths. It compares the monetary savings from reduced transfer time and capital costs for several innovative ideas.

Jan 1, 1994

By Martin N. Kelley

The Great Belt Link is a $3.5 billion fixed link across an 18 km (12 mile) wide body of water that separates the island of Zealand, on which Copenhagen is situated, and the main land mass of Denmark, Jutland, which is part of the European continent. The project consists of three main contracts. The first contract is an 8 km (5 mile) long, two-bore railway tunnel for the eastern half, the second contract is a 6.6 km (4 mile) combination railroad and highway bridge for the western half, and the third contract is a 6.7 km (4 mile) long high-level highway bridge for the eastern half. This paper will discuss the Eastern Railway Tunnel Project and the methods of construction that the joint venture consortium plans to use, along with its equipment selection. The ground conditions to be encountered begin with glacial tills, which are a mixture of clay, silt, sand, gravel, cobbles, and granitic boulders. The boulders can be up to 1-3 m (3-10 ft) in diameter. Underlying the till is a marl which is sometimes highly fractured with hydrostatic pressures of up to 8 bar. About 40% of the tunnel is in till and 40% in marl, with the remaining 20% being a mixed face of the two formations.

Jan 1, 1991