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After a stagnant performance in 1982, gross national product (GNP), industrial production, and employment increased during 1983 in nearly all industrial nations, with the U.S. performance generally leading the uneven worldwide recovery. Real U.S. GNP increased 3.3 percent in 1983 (table I). Although investment in nonresidential structures declined, total nonresidential fixed investment in the United States was up 1.5 percent following a 1982 decrease. The increase in worldwide industrial activity and demand in 1983 put greater pressure on prices in many countries. Prices increased from less than 3 percent in the Federal Republic of Germany, Japan, the Nether-lands, and Switzerland to as much as 10 percent in nearly all the other Organization for Economic Cooperation and Development nations. The annual inflation rate in the United States was 4.3 percent (based on the GNP fixed-weight price index).

Jan 1, 1984

By Hans Ruge

The El Soldado copper mineralization occurs as relatively high-grade irregular ore bodies with assay contacts and with frequent inclusions of barren rock. The sampling method must be timely for production grade control purposes, as well as accurate and inexpensive. Sampling techniques evolved from sampling dump cars at the haulage level to sampling scooptrams at the loading pockets. These were abandoned in favor of sampling production blast holes. Several sampling alternatives are discussed. These involve the selection of optimum volumes and sampling frequencies while taking into consideration geological parameters and statistical analyses of sampling data.

Jan 1, 1984

By Dr. O’Neil Thomas J., Donald W. Gentry

"There are two characters to the value of mining properties-one mine may have a value, owing to its real intrinsic worth; an- other (having no intrinsic value) may have a value by being so situated as to harass the working of the really valuable mine-in mining camps one is looked upon as much of ligitimate enterprise as the other.'' -Victor Clement to Simeon Reed, Wardner, Jan. 11, 1890, Reed Mss. APPROACHES TO VALUATION Value and costs are two terms basic to financial analysis which cause, perhaps, the greatest amount of misunderstanding in mine valuation studies. When discussing the value of an asset or the costs of producing a product, it is absolutely essential that the speaker define the terms being used. There are many types of value and many categories of costs. Without specific accompanying definitions, value and cost data are not very meaningful. Value refers to a measure of the desirability of ownership of property. Some of the types of value which might be encountered in a mine valuation study are: 1) Market value 2) Full cash value 3) Salvage value 4) Replacement value 5) Capitalized value 6) Book value 7) Assessed value 8) Insured value Each of these has a specific meaning which can be applied to determine a monetary amount in a specific situation. The major item of interest here is the broader question of "what is the value of the mine?" or "what is the mine worth?" In this case, we are speaking of market value. Market value is the value (price) established in a public market by ex- changes between a willing buyer and a willing seller when neither is under duress to complete the transaction. Market value fluctuates with the degree of willingness of the buyer and seller and with the conditions of the sale. The use of the term market suggests the idea of barter. When numerous sales occur on a market, the

Jan 1, 1984

By C. J. Toberman

Improvements in fine (28x0) and ultrafine (200x0) coal cleaning is an acknowledged goal with potential benefits in both steam and metallurgical coal markets. This work focuses on adaptation to fine coal flotation of FLOTE, a computer simulation model of the froth flotation process originally developed in the hard minerals field. FLOTE describes the flotation of solids based on particle surface activity, composition, and size. The quasi steady state model was applied to predict flotation performance at an Eastern Kentucky, full scale metallurgical coal preparation plant. Parameter estimation and model testing used detailed flotation test data from a five stage rougher flotation bank. Overall grade/recovery predictions compared well with known plant performance under variation of principally feed grade, plant throughput and reagent addition; however, grade/ recovery predictions for each cell weaken under overloading conditions. Analysis of grade/recovery over a range of sizes is presented. Suggested model improvements and extensions are discussed.

Jan 1, 1984

By Larry F. Brown

Mining has been the mainstay of the Woods Creek Valley for more than a century. The head of the valley is at the Continental Divide, about 50 miles west of Denver, Colorado. First, it was the quest for gold and silver that drew people to the valley. Then, when molybdenum was classified as a strategic metal by the U. S. Government during World War I, it was the valley's molybdenum mineralization which attracted the most attention. Molybdenum is used primarily as an alloying material in superior grades of steel. Circumstances responsible for providing the label "Urad" are unknown, but Urad is variously reported to be an acronym for "Uranium Research and Development" or "Uranium Research of America Division". The search for uranium was fruitless as no ore grade uranium exists in this area. The moly orebody was first developed and mined by the Primos Exploration Company from 1914 to 1919. During World War II, the mine was purchased by the government and turned over to the Molybdenum Corporation of America to operate. In 1963 AMAX Inc. purchased the property for $2 million. After spending nearly $30 million for exploration and development, AMAX put the mine into production again in 1967.

Jan 1, 1984

By Susan G. Bilhorn

A number of studies have been conducted in active and inactive mine environments using continuous monitoring and data acquisition systems to detect various parameters. In addition to the information obtained for research purposes, these monitoring systems can provide a means to remotely collect required information (such as radon daughter concentrations and air velocity) and control various conditions (such as fan operation and air door position) in numerous working sections of an active mine. Selection of detector locations and placement, which are critical to obtain the information and control desired while not inhibiting mine operations and influencing the detector readings, are covered in this paper.

Jan 1, 1984

By James E. Lonergan

Linear goal programming is a multi-objective optimization technique where the constraints of a linear programming formulation of a problem are considered as additional objectives. The optimal solution is the one that comes closest to satisfying all the objectives. An interactive computer program was written to utilize this technique in solving the feed blending problem faced by power plants de- pendent on multiple sources of coal supply. This program determines the amount of coal from each supplier to utilize in the blend. Examples of the use of the program in both long and short term coal procurement planning scenarios are given.

Jan 1, 1984

By J. M. Mutmansky

Procedures for the determination of the operating point that results when a fan is connected to a mine and placed in operation have been a source of confusion for decades. A variety of techniques has been proposed, often to the detriment of the practicing ventilation engineer trying to apply the techniques to the multitudinous mine/fan matching problems encountered in the engineering of mine ventilation systems. This paper proposes some different assumptions and definitions that simplify the solution of problems in determining the operating point. As a result, a set of procedures is provided for determining the operating point of a mine/fan system when the outlet areas of the mine and fan are known. To establish a major simplification in the development of procedures for the determination of the operating point for a mine/fan combination, the authors suggest that the mine pressures be redefined and then used in such a manner that the conservation of energy is ensured. This provides the basis for the recommendation that the fan operating point be determined using the fan total pressure and the system total pressure characteristics. This procedure can be applied to fans in the blower, booster, and exhaust positions equally well and to both single-fan and multiple-fan networks. Another advantage is that the method is applicable to fans with or without an evase.

Jan 1, 1984

By John L. Thames

The benefits of water harvesting as an alternative to conventional reclamation were demonstrated on the Peabody Coal mines in Northeast Arizona. The project produced food crops for four years, and demonstrated that a catchment/crop area ratio of about 2.5:1 was sufficient to obtain sufficient water from the 11 inch annual precipitation to produce garden and fruit varieties in quantities equal to or exceeding national production averages. The economic returns exceeded those of the conventional practice of returning the mine area to rangeland by at least ten fold. Subsidence of the regraded spoil was the only major problem in maintaining the system. Although, water harvesting systems have the potential of providing high economic returns and greater social benefits, as demonstrated by this project they are presently at variance with the strip mining regulation.

Jan 1, 1984

By G. Griffiths

"P. WitteWitteck DevelopmentThe implications of using a tower mill for fine grainding in the ore processing of tailings are significant. What can those of us who are in a research and development situation do when we recommend this equipment to a client? When this prototype is placed on stream next to a conventional grinding mill as you suggest how do we estimate the power requirements and the grind which will be achieved?ReplyLet me explain the Macassa circuit. The tower mill here was running in parallel with one of the ball mills. The feed entering the tertiary system is scalped in a primary cyclone. The finial cut is made in a secondary cyclone. The actual feed to the tower mill is the underflow from the two cyclones and was split to the ball mill and tower mill. During the testing we were unable to isolate the tower mill to determine its contribution to the overall system. We then started to look at the amount of material produced across the mill. We entered the mill at between 17% and 20% finished material and exiting at between 36% and 40% finished material. We were able to project, with a high efficiency classification system, and arrived at 6 Kwh/ton or better."

Jan 1, 1984

By Louis D. Murino

Compared to coal or many metals industries, talc must be considered a small, specialty market catering to niches and dependent primarily on the physical attributes of the mined and processed mineral rather than the chemical attributes with copper, lead or uranium concentrate, the primary objective is the percent metal that ultimately is refined by the smelter, as opposed to the brightness, particle size distribution, trace impurities or morphology. The latter constitute the important determinants of where, how and why talc and similar industrial minerals are used. This paper addresses the talc market-place: where it is, how much of a market there is, who the producers are, available capacity, market growth, and marketing techniques.

Jan 1, 1984

By D. J. Rose

The San Miguel Mine is owned by San Miguel Electrical Cooperative, Inc. and operated by Atascosa Mining Company, a wholly-owned subsidiary of Morrison-Knudsen Company, Inc. This multiseam, single-zone lignite surface mine is located near Jourdanton, Texas, 110 kilometers (68 miles) south of San Antonio. Lignite extracted from four closely-spaced seams is used to fuel the 400-MW San Miguel Power Plant. Recovery depths range from 7 to 37 meters (25 to 120 feet). The mine began stripping operations in the spring of 1980 and now produces approximately 2.5 million tonnes (2.8 million tons) of lignite annually. Atascosa Mining Company is responsible for production, maintenance, engineering, and management services. Production responsibilities include topsoil removal, overburden removal, lignite mining, spoil pile regrading and topsoil replacement, as well as ash disposal and construction and maintenance of water retention and diversion facilities.

Jan 1, 1984

By M. M. Tilman

The Bureau of Mines evaluated corrosion resistance of Split Set friction rock stabilizer mine roof bolts to aid in better prediction of useful service life. Electrochemical corrosion testing was conducted utilizing an automated corrosion measurement system. Natural and/or synthetic mine waters from four uranium and two copper mines were the test media for the two types of high-strength, low-alloy (HSLA) steels from which Split Set stabilizers are manufactured, and for galvanized steel. Tests were conducted with waters of minimum and maximum dissolved oxygen content at in-mine water temperatures. Retrieved Split Set stabilizers were also evaluated for property changes. Galvanized steel was found to be far superior to the unprotected steel in general corrosion resistance; limited tests indicate little ten.dency to pitting, contrary to behavior for the uncoated steel. Copper-bearing HSLA steel was slightly more corrosion resistant than non-copper-bearing HSLA steel. Statistical analyses resulted in development of equations relating dissolved oxygen, chloride, sulfate, and magnesium contents of mine waters to corrosion rates of the two HSLA steels (nongalvanized). An equation was developed that relates corrosion rates of galvanized steel to mine water temperature and dissolved oxygen content. Variable conditions in mine environments make corrosion damage difficult to predict and emphasize the need for corrosion prevention and control.

Jan 1, 1984

By Richard H. Olson

Talc is currently mined in the U.S. in six major districts. The size and depth of the ore bodies and their mineralogy dictate the types of products manufactured and the mining and processing methods which must be employed. The geology of the major deposits is well known and will be but briefly discussed The major emphasis will be placed upon the past history of the districts, the size and depth and configurations of the ore bodies, the ore mineralogy, and how all of these factors govern the types of mining and processing operations which may be employed in each of the districts.

Jan 1, 1984

By W. F. Watts

This report describes a statistical analysis of 41,502 respirable quartz dust samples collected from 1974 through 1981 in metal and nonmetal mines and mills. The goal of this Bureau of Mines study was to identify commodities and occupations associated with high quartz dust exposure so that future enforcement and research activity can be focused on the high-exposure areas. For this analysis, the Bureau used its computerized Mine Inspection Data Analysis System (MIDAS), which contains data on nearly 350,000 air samples, including data for 61 contaminants in 45 commodities. The samples analyzed were collected by inspectors of the Mine Safety and Health Administration (MS HA). The data were entered into the MIDAS computer and coded according to commodity, occupation, location, and other categorical information. Occupations an. commodities with high quartz dust exposure were identified by grouping the data by code categories. Workers at sandstone, clay and shale, and miscellaneous nonmetallic mineral mills had the highest quartz dust exposures. Within these mills, occupations with high exposures were baggers, general laborers, and persons involved in crushing, grinding, and sizing operations. Dust concentrations in these mills were not necessarily the highest, but because the dust contained a high percentage of quartz, the health risk from dust exposure was the greatest.

Jan 1, 1984

By Groves J

The sizing and classification circuits at the Mt. Newman Beneficiation Plant have performed satisfactorily. Investigations have been aimed at solving minor problems and achieving small' improvements. Emphasis has been placed on cost reduction rather than metallurgical performance. It has been found that some circuits will give better performance with the sieve bends removed. 1.0 BACKGROUND Mt. Newman. Mining operates a major iron ore mine in the Pilbara region of Western Australia. Rainfall is sparse (average 250 mm/year). Current mining is all above the water table. What rain there is tends to run off quickly instead of soaking in. The total operation produces about 30 Mt/ year of saleable product. Most of this product comes from high grade crushing plants where ore from the quarries is simply crushed and conveyed to product stockpiles. About 3 Mt/ year comes from the Beneficiation Plant.

Jan 1, 1984

By H. H. Hayden

The accident repeater-40 you have one at your mine? Unless your company is vastly different from most coal companies, you will find that a small percentage (11-12%) of your employees will have a large percentage (47-50%) of your accidents. When you find out that this is a fact, what do you do? First, you establish a set of guidelines that can be used in identifying the ?accident repeater?. Next, you determine the type of action necessary to improve work habits and safety performance of the accident repeater. With these two steps in mind, objectives are developed for an ?accident repeater? program.

Jan 1, 1984

Data released by the Commerce Department's Bureau of Economic Analysis show continued gradual change in the real GNP's rate of growth in 1984, which has eased from an annual growth rate of 10.1 percent in the first quarter lo 7.1 percent in the second quarter, and then to 2.7 percent in the third quarter. The automobile industry strike in the last half of September had only a small effect, estimated at less than a 0.1 percentage point reduction in the growth rate. Among the components that comprise the GNP, personal consumption and fixed investment grew at lower real rates in the third quarter than in the second quarter, while net exports decreased. Personal consumption expenditures increased $0.4 billion in the third quarter, compared with an increase of $20.1 billion in the second quarter. Nonresidential fixed investment increased $3.9 billion in the third quarter, compared with $9.6 billion in the second quarter. The other component of fixed investment--residential investment--increased from $60.8 billion in the second quarter to $61.2 billion in the third quarter. Real net exports of goods and services decreased $1 1.3 billion in the third quarter, compared with a $3.1 billion decrease in the second quarter. Although exports increased from an annual rate of $144.7 billion to $150.2 billion, imports increased much more, from an annual rate of $1 56.2. billion to $172.8 billion (table 1).

Jan 1, 1984

By Yve Aymong

"The objective of this paper is to help readers benefit from the practical experience of persons who have been engaged for several year s in the testing and repair of power transformers. Power transformers are known to be reliable pieces of equipment with expected usage of 25 to 30 years, but simple problems such as leaking radiators, or a bad contact on a tap changer, could shorten the life of a transformer. To ensure a longer life span, transformers should be checked on a regular basis.What is a Power Transformer?It can be a 90 MVA transformer for Hydro-Québec or a power transformer can be a 500 KVA unit in a small hospital. Generally a power transformer is an oil -filled type of 3 to 5 MVA. It can also be a dry type transformer, that should be treated in the same manner as oil-filled transformers, and some of the tests explained in this paper also apply."

Jan 1, 1984

By Jean Dupere

Mr. Chairman, Ladies and Gentlemen, I'd like to take just a moment of your time before we examine the current position of the asbestos industry and its market outlook to take a searching look at the product itself. I feel that if we are to understand the problems that beset this basic mining and manufacturing industry and, more important, if we are to appreciate the solutions to these problems that I plan to put forward in a few moments' time, then we had better look at asbestos from the proper perspective. Asbestos has a unique combination of properties - properties not found in any other natural substance or man-made material. This has resulted in asbestos finding its way - in fact, being welcomed - into literally hundreds of applications.

Jan 1, 1984