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By Lawrence L. Davis

This chapter includes tables for 1981 that were not available in time for publication of the 1981 Minerals Yearbook, but does not include corresponding tables for 1982. The value of raw nonfuel minerals produced in the United States during 1982 was estimated at about $20 billion, a decrease of $5 billion compared with that of 1981. The decline in value is the first since 1971 and is the largest percentage drop since 1938. Although the domestic mining industry continued to be troubled by difficulties in attracting capital and by import competition from countries with lower overall production costs, the principal cause of the decline was sharply decreased demand brought on by the worldwide economic slowdown. Metal commodities were impacted most severely with only 4 of 21 metals registering production value gains and only 3 of 21 showing production quantity increases. Overall metal production value decreased 37% from that of 1981, a reflection of the domestic slowdown in the automobile and construction industries, which are major metal users, Overall production value of nonmetals decreased 12% compared with that of 1981, with only 14 out of 44 nonmetals showing increases. Nonmetal production quantities increased over 1981 for only 6 of the 44 nonmetals.

Jan 1, 1983

By Richard G. Geyer

One aspect of a program to improve the chances of survival following coal mine disasters is the development of a communications system which will allow surviving miners to make their circumstances known to rescue teams. Various communications techniques can be considered, including electromagnetic systems, acoustic systems, and hybrid systems. The electromagnetic and acoustic systems would be independent of existing mine communications systems and set up specifically for use in emergencies. Hybrid systems might use a short emergency link to existing telephone systems in the mine. Many variations are technically possible, and the primary task is in evaluating the relative merits of each, so that the most workable system can be selected.

Jan 1, 1973

By Oscar Lee

"Flotation is generally regarded as a process that is only applicable to metallic minerals. However, its scope is now known to be greater than this, because some of the nonmetallic minerals are floatable, such as graphite, sulphur, and fluorite. Recent observations show that limestone may be added to the list of floatable nonmetallic minerals. Such work is being done on a laboratory scale at the Southern Experiment Station (Tuscaloosa, Ala.) of the Bureau of Mines, Department of Commerce, where experimental magnetic concentration of the low-grade iron ores of the Birmingham district is in progress. Certain experiments have demonstrated that the limestone may be floated from the magnetic log-washer tailing, and then incorporated in the iron concentrate.If the loss of lime could be prevented, some ores though low in iron and high in insoluble contain enough lime to make their concentrates self-fluxing. Since this loss in the magnetic log-washer can not be avoided, the Time must be recovered from the tailing by some method and added to the magnetic iron concentrate before sintering. Then the resulting concentrate will be self-fluxing.While seeking a suitable means of treating the tailing for recovery of lime, flotation was tried. It was at once evident that this method had possibilities, during the early part of the investigation, soap solution made from a common soap was used as a flotation reagent. The froth obtained was a fairly good lime concentrate. This result was an important clue, and led to tests with the use of such reagents as oleic acid and sodium oleate. Later, cresol, creosote, coal tar and other similar flotation reagents were tested in combination with the oleic acid and soap solutions. As a result, oleic acid and cresol used together were found to be satisfactory.The tailing from the magnetic log-washer is in excellent physical condition fur flotation. The iron ore had been ground in a ball mill to 100 mesh for magnetic concentration. Hence the bond between the lime carbonate and the other constituents of the tailing was well broken."

Apr 1, 1926

By S. R. Zimmerley, John Gross

"The investigation discussed in this paper was undertaken to obtain fundamental data on crushing and grinding and has been confined, so far, to work on quartz.The results of crushing or grinding have hitherto been judged entirely by the amount of the various-sized particles produced, based. on sieve sizing for particles above 74 microns in size and on microscopic measurement or elutriation for particles below 74 microns - a method which could give only a general idea of what had been accomplished.There was a distinct need of a ""yardstick"" for the measurement of crushed material. It appeared that no advance in the fundamental investigation of crushing and grinding could be made without a reliable method of surface measurement and that such a measurement would have to be based on some property of the surface of the crushed material.A number of attempts based on various surface actions, such as adsorption and heat of wetting, were made to measure surface on quartz particles, but all gave unsatisfactory results. After some preliminary work it was decided that a dissolution method based on Wenzel's law-- ""the reaction velocity between solids and liquids is proportional to the area. of contact""4 -- would be the most feasible.Early use of the dissolution method had been made for surface measurements5, and lately Dr. Geoffrey Martin and his coworkers in England used the dissolution method to determine surface on quartz. They compared the amount of quartz dissolved from a sample in one hour by a hydrofluoric acid solution, with the amountdissolved from a measured quartz cuboid6,After investigating the solvent power of sodium carbonate, sodium hydroxide, and hydrofluoric acid for quartz, hydrofluoric acid was selected as the most suitable solvent, and a dissolution method was developed which gives very reliable results.During the dissolution of quartz in hydrofluoric acid, the reaction velocity changes for two reasons: there is a change in concentration of solution, and a change of surface of the solid. The amount of quartz dissolved in a definite period of time is therefore not a true measure of surface. If, however, the reaction velocity or rate of dissolution for various periods of time be plotted, a curve will be obtained which, if extrapolated to the zero time ordinate, will give the rate of dissolution before any change of surface or any change in the solvent has taken place, and which is a true index of surface. This rate of dissolution, expressed in percentage of the original sample at the zero time ordinate, is designated herein as the ""Initial Rate"" or as simply ""I. R."""

Jul 1, 1928

By Nancy S. Raymon

The Bureau of Mines investigated the effect of controlled additions of selected metal oxides, as well as the adjustment of the calcia-to-silica ratio on the high-temperature strength of refractory-grade periclase. Increases in the hot flexural strength of some periclase materials in the range of threefold to fourfold were obtained with additions of Zr02 and by adjustment of the CaO:Si02 ratio to the 2.5 to 3.0 level. Results show that for each periclase refractory raw material, there exists a combination of level of Zr02 addition and an adjustment to the CaO:Si02 ratio that optimizes the hot flexural strength of each of these materials. Data also indicate that the improved hot strengths can be attributed to the high-temperature secondary phases formed between the different levels of periclase impurities and the additives, resulting in improved intergranular high-temperature bond strength.

Jan 1, 1982

By Thomas P. Mucho, Dennis Dolinar, Christopher Mark

During the 1990s, the former U.S. Bureau of Mines conducted a number of field studies in which the performance of different types of roof bolts were evaluated in different geologic environments. The studies used a standard suite of measurements, including multipoint extensometers, strain-gauged roof bolts, and roof bolt load cells. The sites were chosen to investigate the effect of a variety of parameters, including installed tension, bolt capacity, grout annulus, and horizontal stress orientation. Although not fully successful, the measurements provided valuable insights into each of these issues. They also showed that instrumentation and monitoring have important advantages over observational methods for comparing the performance of different roof bolting systems.

Jan 10, 2000

By J. W. Miller

An investigation was begun by the Bureau of Mines in 1948 to determine the preparation characteristics of American coals. Results of the investigation were planned to be reported on a county basis and from the data developed to determine: 1. Which coals either as mined or after beneficiation by conventional preparation are chemically suitable under present standards for producing metallurgical coke. 2. Which coals require special and more intensive treatment in preparation than is now practiced. 3. Which coals cannot be considered potential sources of metallurgical coke, regardless of preparation by present-day methods. This report is one in this county series that describes the preparation characteristics of the coals of Lee County, Va.

Jan 1, 1957

Aid mine workers in detecting hazardous roof conditions in underground mines by developing a method of roof sounding which supplements or replaces the traditional roof sounding technique where the miner relies on experience to determine whether or not the rock is sound. Approach The Bureau of Mines developed an electronic roof sounding de-vice that acoustically determines the integrity of mine roof rock by "listening" to the variation in frequency vibrations within the rock. How It Works n previous research, the Bureau of Mines found that loose rock in a mine, when impacted, vibrates at a much lower frequency and for a lower time period than does a solid slab. By quantifying the enhancement of low frequency vibrations in loose rock over solid rock, a repeatable, objective measure of the rock's soundness can be obtained. This approach was used in developing the rock stability tester.

Jan 1, 1986

By H. J. Sloman

"INTRODUCTION Industry, including coal mining, has come to realize that to prevent accidents the human element must be given more consideration than was customary in the past. In formulating safety rules and regulations and in the enactment of laws governing mining, too often enforcement is emphasized rather than the means of gaining willing compliance.' The purpose of this paper is to call attention to the human side of accident prevention, and the approach to this important and much-discussed subject will deviate somewhat from the usual discussions.The human being is a complex mechanism, both physically and mentally. It is difficult to establish a common denominator for the actions of humans, except in general. In establishing mining laws, rules, regulations, and standards, the ultimate objective should be to gain the best possible response of workmen, so that optimum results in accident prevention may be obtained. The complexity of human beings is apparent when the many ways 1n which they differ are considered. Some of these differences are manifested in emotional and phlegmatic types, degrees of intellect or native intelligence; and in hopes, desires, aspirations, and philosophies of life. How much simpler ac¬cident prevention would be if the response to laws, rules, regulations, or standards were equivalent to the definite movements of puppets responding to pulls on strings. Each time, the strings are pulled in exactly the same way, the puppets will respond in exactly the same manner. Human beings, although having many similar characteristics, do not respond uniformly to identical ""string-pulling""; therefore, much study is necessary before the desired re¬sponses can be obtained. To achieve the ultimate in accident prevention, it must be ""worked at"" constantly. Regardless of the adequacy of safety laws, rules, regulations, or standards, good accident records will not ""roll in"" if dude consideration is not given to the personal traits of those most likely to be involved in accidents."

May 1, 1948

Use water-jet-assisted cut-ting technology to reduce the exposure of mi ne workers' to respirable dust. Approach Install water-jet-assist on mining machines and evaluate its impact on respirable dust. How It Works Water-jet-assisted cutting involves a mechanical cutting bit working in combination with a moderate pressure (generally up to 10,000 psi) water jet directed just in front of, or through, the bit tip. One of its advantages is reduced dust generation because the jet wets the face of the material being cut more efficiently than a conventional low-pressure water spray, thus capturing much of the dust before it ever becomes airborne. It also removes loose cuttings ahead of the bit before they are pulverized by the bit into respirable dust. Total water consumption is about the same as for conventional low pressure dust control water spray systems. However, there is some increase in power consumption because of the energy needed to provide the high pressure water.

Jan 1, 1987

The U.S. Environmental Protection Agency (EPA) and the U.S. Congress are presently considering several approaches aimed at reducing the amount of lead in the environment and society's exposure to lead. One approach is to tax domestic primary lead production or consumption. Objective To assist the Congress and the EPA in their decisionmaking, a study was initiated by the U.S. Bureau of Mines, which assesses the minerals related implications of a tax on U.S. primary lead production and primary lead imports. This investigation analyzes the impacts of a primary lead lax on: (1) domestic primary lead production, (2) domestic lead coproduct and byproduct production (including bismuth, cadmium, germanium, indium, silver, and zinc production), (3) domestic secondary lead production, (4) lead imports, (5) domestic lead recycling activity, and (6) the U.S. lead price. Study Findings Domestic Primary Lead and Primary Lead Coproduct and Byproduct Production. A quantitative analysis based on the application of the Bureau's Supply Availability System (SAM) has been conducted to determine the impacts on domestic primary lead and primary lead coproduct and byproduct production from domestic lead source material for a range of taxes.

Jan 1, 1992

To provide for continuous remote sensing of carbon monoxide (CO) in underground mines. The Approach A transducer module has been developed as a wall-mounted, continuously operating instrument that will measure ambient levels of CO, and produce a signal that is proportional to the concentration.

Jan 1, 1982

By F. J. Smith, W. A. Gallagher, C. A. Herbert

"INTRODUCTION A fire started about 10 a.m., November 10, 1947, at the Kings mine, Princeton Mining Co., Princeton, Ind., about 1,800 feet inby the main shaft bottom on the main west haulage road at a point estimated to be 2 miles from the faces of the main west entries. No lives were lost, as 27 men escaped from the mine after a series of explosions, which necessitated sealing the mine on the surface. This information circular shows"" how adverse conditions might be overcome, when reopening a sealed mine, by expert planning and close cooperation on the part of various organizations. Conditions found in the mine after it was reopened were comparable to the worst that had been anticipated, yet the mine was recovered with comparatively little difficulty and a minimum of risk. The open workings in the mine covered a vast area, but most of the mine resumed production of coal after being sealed for only 37 days.The information contained herein also points to the desirability of adhering as closely as possible to a predetermined schedule of operations."

Feb 1, 1949

In This Chapter [Ventilation: dilution and displacement Water sprays: wetting and airborne capture Water additives: foam and wetting agents Dust collectors: filtration efficiency and inlet capture efficiency Reducing the generation of dust for cutting, drilling, blasting, crushing, and conveying] [This chapter will give you a general perspective on what works or doesn’t work. The chapter will also help if your dust control problem doesn’t fit any of the circumstances described in later chapters. ] This chapter describes the three major control methods used to reduce airborne dust in tunnels and underground mines: ventilation, water, and dust collectors. It also describes methods to reduce the generation of dust, so less has to be removed from the mine air. The ventilation methods provide the best use of air in the vicinity of workers and in the vicinity of dust sources. In this sense, the methods described are local ventilation methods. Most of the emphasis is on so-called displacement ventilation because it is the most effective dust control technique available. The section on water sprays outlines the dual role of sprays—wetting and airborne capture—and describes why wetting is more important. It also corrects some of the misconceptions about spray effectiveness and describes circumstances where sprays can actually increase the dust exposure of workers. The section on dust collectors outlines the circumstances under which dust collectors can be expected to function effectively. It also describes some common design and maintenance problems. The final section describes how to reduce the amount of dust that gets into the air in the first place, since once the dust is airborne it is always harder to control.

Jan 6, 2003

By G. B. Atkinson

To develop technology to help assure an ample domestic supply of zinc, the Bureau of Mines is investigating an aqueous chlorine-oxygen leaching process for treating complex sulfide concentrates. This report discusses the purification of aqueous C12-02 leaching solutions by utilizing zinc cementation to remove Cd, Co, Cu, Ni, and Pb. Additional processing of the purified solution is necessary to produce ZnC12 crystals suitable for molten-salt zinc electrowinning cells. The effects of solution temperature, reaction time, zinc dust concentration, ZnCl2 concentration, and degree of agitation on the removal of impurities were investigated for both simulated and actual leaching solutions. Zinc dust addition to a leaching solution at 30° C decreased the Cd, Cu, Ni, and Pb concentrations to acceptable levels of less than 3 mg/1 each. By increasing the solution temperature to 75° C, the cobalt content was decreased to less than 5 mg/l, an acceptable level for producing electrolytic cell-grade ZnC12. Impurity removal rates from ZnCl2 solutions are Pb>Cu=Cd>Ni>>Co. An increase in the solution temperature increases the rate of removal for these metal impurities.

Jan 1, 1982

By Launa Mallett, Charles Vaught, Michael J. Brinich

The lack of good communication is a very real problem in mine emergencies. Sometimes critical information is not communicated to those who need it to make decisions. At other times, those on the receiving end of a warning do not think to ask the right questions. What happens in underground coal mine fires is a case in point. The authors interviewed 48 workers who escaped three serious fires in western Pennsylvania. In each case the location of the fire was known but did not get communicated to many of those who had to evacuate. Sometimes, even the nature of the problem was not clearly communicated. Some workers began their evacuation knowing nothing about what was happening. In an effort to improve emergency communication National Institute for Occupational Safety and Health (NIOSH) researchers worked with safety professionals to determine what sorts of information are critical in a mine emergency. An extensive list was generated, which proved too long to be remembered by individuals. The list was therefore collapsed into six categories. A communication protocol was derived from these categories.

By A. N. Styler

As part of its water-jet assisted rock cutting research, the Bureau of Mines has initiated a study into the mechanism of rock fragmentation by water-jet-assisted mechanical tools. The objective of this research is to increase coal extraction efficiency by seeking an improved understanding of the synergistic relationship between mechanical cutters and water jets, enabling the design of more effective cutterheads. Rock chips collected during laboratory traverse speed jet-assisted cutting tests were analyzed with respect to the size distribution of the chips and the forces measured during cutting. As the water-jet pressure was increased, the size distribution of the product became coarser with V-face type cutting tools producing less fine material than conical cutting tools. Fracture mechanics theory accounted for less than 10 pet of the energy consumed during fragmentation of the rock. The energy consumed by processes other than rock breakage decreased with the use of water jets and increasing advance rate.

Jan 1, 1987

By Jack C. White

Studies were made to determine the character and distribution of the copper lost in copper mill tailings. Acid soluble (oxide) and acid insoluble (sulfide) copper were determined for heavy-liquid sink and float products of screen-sized fractions from 12 copper mill tailings. In most of the tailings studied, the coarse-size fractions are higher in copper grade than the respective bulk tailings, high in sulfide copper, and low in oxide copper. Oxide copper occurs predominantly in the minus 325-mesh "slimes." Microscopic examination of heavy-liquid sink products indicated that recovery of liberated copper sulfide minerals is complete in most mills, and that copper minerals not being recovered are locked with gangue particles. Additional copper could probably be recovered from most tailings by size classification, scavenger froth flotation of the coarse fraction, and regrinding of the concentrate to achieve liberation of the locked sulfides.

Jan 1, 1971

By S. B. Levin

"INTRODUCTION An exposure of large beryl crystals in pegmatite on Beryl Mountain, in Sullivan County, N. H., was the basis for investigation by the Bureau of Mines to determine the extent of the beryl mineralization and to expose other parts of the same zone that were favorable for additional beryl-rich shoots. Testing by surface cuts, trenching, and tunneling was conducted by the Bureau of Mines from August to December 1943.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to the national security and economy. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes samples and makes beneficiation tests. The field work was supervised by Paul M. Tyler, regional engineer, and John D. Bardill, district engineer. S. B, Levin was in direct charge of the project.LOCATION AND ACCESSIBILITYThe deposit is on the northeast slope of Beryl Mountain, 1 mile south of the village of South Acworth. The village, on State Highways 101 and 123a, is 12 miles northeast of Bellows Falls, Vt. The deposit is reached from South Acworth over a gravel-surfaced road and about 1,000 feet of good truck trail (fig. 1).The nearest railroad siding is at Cold River, on the Boston & Maine Railroad, where there is also a fairly modern, but now idle, feldspar mill."

Mar 1, 1948

To reuse chromium, nickel, and molybdenum now lost in stainless and specialty steel-making wastes, and simultaneously to overcome the current environmental problem resulting from landfilling these wastes. Approach A variety of stainless and specialty steelmaking wastes are agglomerated and recharged into the plant's electric arc furnaces. How It Works Stainless and specialty steel-making wastes such as bag-house dust from the electric arc furnace, dust from the argon-oxygen decarburization unit, grinding swart, and mill scale are blended in proportion to the ratio in which they are generated. Next they are agglomerated on a pelletizer with an addition of a small amount of carbonaceous reducing agent, and air-dried in preparation for being recharged into the furnace. Some mixtures of wastes tested in the laboratory required the addition of binders and/or the use of ovens in lieu of air-drying to produce sufficient pellet strength. Although the optimal maximum particle size of wastes being pelletized is 35 mesh, somewhat larger particle sizes were satisfactorily pelletized during in-plant tests. The photograph shows a typical mixture of wastes and the pellets made from them.

Jan 1, 1981