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By J. M. Singer

The Bureau of Mines investigated the threshold of dispersal of monolayers and piles of rock dust, anthracite, and Pittsburgh seam coal dust in a small wind tunnel that simulated a coal mine gallery, with the objective of preventing or limiting the formation of flammable dust clouds. The effect of selected variables on entrainment velocity was examined. Mode of entrainment and flow processes in the wake region of dust configurations were investigated by means of high-speed motion pictures. Significant results were as follows: 1. Local minimum air velocities required for dispersal were only slightly higher for shallow dust ridges than for dust particles. 2. Minimum velocities for entrainment of dust particles from smooth glass and coal surfaces increased in the order rock dust, anthracite, Pittsburgh seam coal. 3. The mechanism for dispersal of dust poles depended significantly on dust pile geometry, cohesiveness of dust, bulk density and compaction of dust, adhesive surface, and vibrations perturbing the supporting surface.

Jan 1, 1969

By Raymond B. Ladoo

Toward the end of 1920 , the average grades of ground feldspar offered to the pottery industry were so poor and so generally unsatisfactory that many of the largest consumers decided to take active steps for their own protection . A few of the potters made arrangements to grind their own feldspar , while others asked the Bureau of Mines to make a detailed study of the problem and to suggest methods of improvement . Accordingly such a study was undertaken, the partial results of which are outlined in this preliminary report . The outstanding features of the present feldspar industry which are of interest in this connection are stated below. (1 ) Many grinding companies do not own or control all or even a major part of their sources of crude material , but buy in job lots from many sources . (2 ) There is great need of more adequate engineering and chemical control over mines and mills . ( 3) ~ Out of date , inefficient methods and equipment for mining and grinding are in common use . (4) Little or no cooperation exists between feldspar producers , but on the contrary many feldspar companies are exceedingly secretive . This tends towards (a) preservation of obsolete methods ; ( b ) want of knowledge of the essential features of production , market requirements , and the relation between total milling and consuming capacities of the country; ( c ) inefficient and often mistaken trade practices ; ( d) unprofitable and even ruinous competition in dull periods . (5) The small size of many feldspar deposits precludes maintenance of an efficient organization at each individual mine . ( 6 ) Many of the best deposits of feldspar situated close to railroads are becoming depleted , which results in gradual lowering of grades , and increase in cost for better grades . (7) There is a lack of exact mowledge of the ceramic properties and behaviour of feldspar by some consumers , which results in ( a) purchase of feldspar on the basis of price alone , thus encouraging low production costs at the expense of quality , and ( b) inefficient and expensive cross- hauling of both crude and ground feldspar .

Jan 1, 1922

By F. W. Wood

A program of research was conducted by the Bureau of Mines to investigate anomalies in electrical-discharge behavior during consumable-electrode arc melting of titanium and to study the effects of these irregularities on arc-furnace explosions. A major effort was devoted to an experimental survey of arc behavior and a qualitative definition of discharge phenomena.3/ An important conclusion was that the "glow" of industrial arc-melting terminology is not a glow discharge but a skittering arc in a displaced position. The conditions that permit displaced skittering were tentatively defined. The displaced skittering arcs tended to damage melting crucibles in two ways, and details of possible mechanisms leading to crucible rupture and explosive reactions have been proposed accordingly. However, no acceptable means of preventing crucible damage was discovered.

Jan 1, 1961

By Leonard Obert

This Bur of Mines investigation considers the deformational behavior (creep) of pillars made from three quasi-plastic rocks--salt, trona, and potash ore. The first phase of this study considers the design of a model pillar suitable for creep tests; in the second phase, six model pillars prepared from salt from two sources, from trona, and from potash ore. The pillars in each group were subjected to a different but constant axial stress, and the axial strain was measured for 1,000 hours.

Jan 1, 1965

Auger operations produced 14 million tons of coal in 1974, or approximately 5% of all surface mined coal. It was the most efficient of all coal mining methods, producing 40.0 tons per man-day. Exhibit 1.1 gives a breakdown of productivity of all coal mining methods. Exhibit 161 PRODUCTIVITY OF COAL MINING METHODS (Short tons per man-day) [Method - 1971 1972 1973 1974 Conventional 11.00 10.00 9.75 9.30 Continuous 13.00 12.50 12.25 11.90 Strip Mines 35.69 35.95 36.00 36.00 Auger Mines 39.00 43.00 45.33 40.00 ] Unlike other surface mining methods, augering produces clean coal, largely uncontaminated by foreign materials, other than those existing in the coal seam itself. However, compared to other methods, the coal recovery rate is relatively low. For example, a triple-headed auger in a 35-inch seam would recover approximately 50% of the coal in the seam as compared to a 90 to 95% recovery rate for strip mining and a 55 to 65% recovery rate for deep-mining. The low auger recovery rate is due to the circular cuts and pillars left in the seam.

Jan 1, 1975

By Albert L. Toenges

The Deep River coal field is in Chatham, Lee, and Moore Counties, N. C. The coal-bearing part of the basin is about 35 miles long and 5 to 10 miles wide. Sanford, the county seat of Lee County, is the largest town in the area, with a population of 10,000. Four railroads provide transportation to the area, and four United States highways and improved county roads provide easy access to the field. The Carolina mine at Farmville is the only operating mine in the field. The mine was opened in 1921 by two rock slopes driven from the surface to the Cumnock bed. Mining operations continued intermittently until 1945 and then stopped. In the fall of 1947 the mine was reopened by the newly organized Raleigh Mining Corp.

Jan 1, 1952

By E. J. Murphy, A. P. Rowles, John C. Holtz

"INTRODUCTION The use of sheaths or hollow cylinders of flame-extinctive materials surrounding cartridges of permissible explosives has been developed during the last few years; the history of sheathed explosives in their salient development in Belgium was treated recently in a publication of the Bureau of Mines. 6/ This development is of great interest in explosives technology, for it holds possibilities of reducing further the ignition hazards that may cause many coal-mine disasters. The township interest in sheathed explosives in this country is attested by the passage of some State laws permitting the use of such explosives on shift 7/; inquiries are received in increasing numbers concerning the effects of sheaths on practical hazards as well as the general technology underlying their use."

May 1, 1943

By D. R. Wilburn

The Bureau of Mines investigated the potential availability of magnesium from 45 properties in market economy countries (MEC's). The 38 significant deposits evaluated have demonstrated resources of approximately 29 billion short tons (st) magnesium-bearing material containing 416 million short tons (MMst) magnesium oxide (MgO). Using data it gathered, the Bureau determined the magnesium production potential for each property including a 15-pct rate of return on invested capital. Total and annual availability assessments for the next 30 yr were completed for magnesium (Mg) metal, deadburned MgO, and caustic calcined MgO. At a January 1984 market price of $1.34/Ib Mg metal, the properties evaluated could economically produce an estimated 13 MMst Mg metal. At a market price of $400/st nonmetal magnesium product, these properties could economically produce 109 MMst deadburned MgO and 43 MMst caustic MgO. These properties could produce approximately 301,000 st Mg metal, 3.0 MMst deadburned MgO, and 430,000 st caustic MgO annually at current full production levels and 1984 market prices until at least the year 2000. Total 1984 MEC production assessed in this study was 153,000 st Mg metal and 4.3 MMst nonmetallic MgO products.

Jan 1, 1986

By J. R. Koehler

The U.S. Bureau of Mines (USBM) ground control research program includes several projects focused on developing design criteria for yielding-pillar-based longwall gate road systems. As part of this program, mining practices at the Sunnyside Mines, Sunnyside Reclamation and Salvage Co., Sunnyside, UT, are being documented to preserve the long history of yield pillar system evolution on the property. Published information describing the specific in-mine performance of the numerous gate road configurations utilized at the Sunnyside Mines is very limited. To overcome this deficit, USBM personnel interviewed 30 longtime mine employees representing nearly 700 years of mining experience at the Sunnyside operations. Mining conditions in 12 specific areas in the Nos. 1, 2, and 3 Mines were discussed in the interviews. Also, broad topics such as general mining practices, safety, and geology were often addressed during the discussions. Comprising the body of this report is an extensive record of the events and conditions experienced while mining the identified areas. In addition, eight significant conclusions were developed that accurately summarize the general opinions of the interviewed personnel regarding mining conditions and practices at Sunnyside.

Jan 1, 1994

By M. M. Gilkey

This report on water requirements for the New Mexico mineral industry includes data on industrial operations closely related to mineral production. It contains general information concerning public water supplies at five principal cities and a short discussion of water needs for agriculture. Background data are presented regarding the geography, hydrography, and water laws of New Mexico, as well as precipitation and evaporation characteristics of the State. Most of the information on source, quantity, distribution, cost, and treatment of water was obtained in interviews with company representatives. Water systems at 46 operations are illustrated by schematic waterflow diagrams. The study revealed that the New Mexico mineral industry in 1962 used about 16 billion gallons of new water and reused 152 billion gallons, a total usage of 168 billion gallons. Consumption amounted to 7.6 billion gallons. Of the 16 billion gallons of new water, 11.9 billion gallons was "self- supplied" from ground water sources, and 2.6 billion gallons was self supplied from surface sources. Approximately 1.5 billion gallons was purchased. Some of the water from company-owned wells is piped as far as 30 miles. Reported costs of the self-supplied new water range from 1 to 20 cents per 1,000 gallons and average 8 cents per 1,000 gallons for power and maintenance. Inadequacy of the supply of new water at many operations necessitates large-scale recirculation. Reported costs for recirculating water (power and maintenance) average 1.8 cents per 1,000 gallons. For the entire New Mexico mineral industry in 1962, the value of product was $42 per 1,000 gallons of new water intake and $88 per 1,000 gallons consumed. Analyses of 40 water samples, listed in the appendix, show the wide range in water quality at plants throughout the State. Projection of the 1962 water requirements of the mineral industry indicate that the total demand for new water will increase from the 16 billion gallons used in 1962 to 24 billion gallons in 1980, a 50 percent increase; and to 36 billion gallons in 2000, which is 125 percent more than the 1962 intake of new water.

Jan 1, 1965

By M. M. Gilkey

This report on water requirements for the New Mexico mineral industry includes data on industrial operations closely related to mineral production. It contains general information concerning public water supplies at five principal cities and a short discussion of water needs for agriculture. Background data are presented regarding the geography, hydrography, and water laws of New Mexico, as well as precipitatton and evaporation characteristics of the State. Most of the information on source, quantity, distribution, cost, and treatment of water was obtained in interviews with company representatives. Water systems at 46 operations are illustrated by schematic waterflow diagrams. The study revealed that the New Mexico mineral industry in 1962 used about 16 billion gallons of new water and reused 152 billion gallons, a total usage of 168 billion gallons. Consumption amounted to 7.6 billion gallons. Of the 16 billion gallons of new water, 11.9 billion gallons was "self- supplied" from ground water sources, and 2.6 billion gallons was self supplied from surface sources. Approximately 1.5 billion gallons was purchased. Some of the water from company-owned wells is piped as far as 30 miles. Reported costs of the self-supplied new water range from 1 to 20 cents per 1,000 gallons and average 8 cents per 1,000 gallons for power and maintenance. Inadequacy of the supply of new water at many operations necessitates large-scale recirculation. Reported costs for recirculating water (power and maintenance) average 1.8 cents per 1,000 gallons. For the entire New Mexico mineral industry in 1962, the value of product was $42 per 1,000 gallons of new water intake and $88 per 1,000 gallons consumed. Analyses of 40 water samples, listed in the appendix, show the wide range in water quality at plants throughout the State. Projection of the 1962 water requirements of the mineral industry indicate that the total demand for new water will increase from the 16 billion gallons used in 1962 to 24 billion gallons in 1980, a 50 percent increase; and to 36 billion gallons in 2000, which is 125 percent more than the 1962 intake of new water.

Jan 1, 1965

By F. A. Rutledge, B. S. Webber, J. M. Moss

"INTRODUCTION The United States, with its vast resources of relatively low-grade zinc been the world's leading producer of zinc -metal for many years. The expanded zinc production during the period, 1939-44, inclusive, was induced by favorable premium prices and has depleted the known ore reserves in the United States. The 1943-44 rate of zinc production cannot long be maintained in the United States, especially if premium prices are removed. Domestic zinc reserves, have been depleted to such an extent that it is doubtful if our mines will again be able to completely and continually fulfill the needs of this country.The Bureau of Mines, anticipating a postwar consumer demand for 550,000 to 750,000 tons of slab zinc and an additional 100,000 tons for use in paints and chemicals, sent two engineers to Sedanka Island in July 1945 to investi¬gate the deposits near Biorka Harbor.ACKNOWLEDGMENTIn its program of exploration 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 national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion the Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director."

Nov 1, 1946

By J. W. Miller

Depletion of coals most suitable for metallurgical fuel has made necessary a general survey of coking coal reserves in the United States. These investigations were begunn 1948 at the joint request of the Munitions Board, Department of Defense, and a number of coal companies. This report, which is one in a series, by counties, describes the preparation characteristics of the coals of Harlan County, Ky. From these data it is possible to determine: (a) Which coals, either as mined or after beneficiation by conventional preparation, are chemically suitable under present standards for producing metallurgical coke, (b) Which coals require special and more intensive treatment in preparation than is now practiced; and (c) Which coals cannot be considered to be potential sources of metallurgical fuel regardless of preparation.

Jan 1, 1955

By W. A. Stickney, J. W. Town

Studies on continuous - circuit leach - aluminum precipitation and leachelectrodeposition of mercury were made by the Bureau of Mines to determine optimum conditions and cost estimates for recovering mercury from mercury sulfide flotation concentrates . With 150 grams of sodium sulfide and 50 grams of sodium hydroxide per liter , from 98 to 99.8 percent of the mercury was extracted from flotation concentrates , with about 0.5 pound of sodium hydroxide used per pound of mercury produced . Precipitation of mercury from the caustic - sulfide solution with minus 8 - mesh aluminum shot required about 0.2 pound of aluminum per pound of mercury produced at a cost of $ 0.05 per pound of mercury . Electrodeposition cost with 7 mill power , based on 50 percent current efficiency , was below 2 mills per pound of metal deposited . Feed solutions ranged from 10 to 130 grams of mercury per liter , and current densities , from 2 to 70 amperes per square foot . The cost of open- pit mining 250 tons per day was estimated at $ 1.75 per ton , and flotation - leachingelectrodeposition of the ore , at $ 3.54 , resulting in a cutoff grade of about 0.1 percent mercury . The cost of underground mining 50 tons per day was estimated at $ 20.00 per ton , and the cost of milling the ore was estimated at $ 13.33 , which resulted in a cutoff grade of 0.6 percent mercury .

Jan 1, 1964

By R. S. Warfield

The Kasna Creek copper deposit near Lake Kontrashibuna in the Lake Clark region, Alaska, was the object of an investigative project by the Bureau of Mines during the fall of 1948. Recessed because of inclement weather, it was completed in 1949. This project was a part of the Bureau of Mines program in Alaska for the development of critical and strategic minerals. The ore bodies are contact-replacement deposits in limestone. Mineralization is mainly specular and micaceous hematite associated with chalcopyrite, calcite, chlorite, quartz, and amphibole. The deposit, on the right limit of Kasna Creek approximately 2 miles from the shore of Lake Kontrashibuna, is composed of two mineralized zones that range in altitude from 2,350 to 2,650 feet. This report contains a brief history of the prospect, description of the physical setting of the property, its geology, and the factual results of the Work performed by the Bureau of Mines.

Jan 1, 1951

By R. V. Higgins

This paper describes a method and a computer program for calculating shape factors and areas of channels that turn more than 90° and conduct fluids into the backs of wells. The program represents an improvement over a previous Bureau of Mines investigation by using a 4-point Lagrange interpolation equation instead of a 3-point and by summing areas of trapezoids with either x altitudes or y altitudes. Some of the techniques reported in this paper can also be used to compute the areas between contours and the lengths of lines that turn more than 90°.

Jan 1, 1968

By Thomas C. Atchison, Joseph M. Pugliese

Six explosives were compared by measuring their strain- producing abilities in limestone . Peak strain , e , varied with scaled distance , R/Ro , according to the following equation : € = Kc (R /R 。)- ". The distance exponent , n , was a constant of the rock and did not depend upon explosive . The strain intercept , Ke , increased with increasing detonation pressure of the explosive . The strain intercept also depended upon the explosive- to - rock impedance ratio . For impedance ratios from 0.53 to 1.38 , the strain intercept was approximately proportional to the medium stress , Pn , as calculated from the explosive detonation pressure , P , and the explosive - torock impedence ratio , Z , by the simple elastic theory relation : P = 2P / ( 1 + Z ) . PD However , the data indicated that , at lower values of impedance ratio , the strain intercept is relatively larger than would be expected from the simple elastic theory . The results presented provide a simple method for predicting the relative effectiveness of different explosives in breaking limestone from the detonation pressures and characteristic impedances of the explosives .

Jan 1, 1964

By G. L. Anderson

The critical importance of wire rope integrity to the mining industry has led to the creation of standards for the retirement of wire rope as well as to the development of electromagnetic devices and procedures that would allow wire ropes to be tested against these standards without destroying them, The U.S. Bureau of Mines (USBM) conducted research to evaluate these devices by measuring loss of metallic cross-sectional area and the number of wire breaks, or local faults. The intent was to define the extent to which the technique can identify degradation within the rope, e.g., broken wires, corrosion, and wear. Experimental results showed that instrument sensitivity depended on a number of factors, including rope diameter, placement of sensors, location and characteristics of flaws, rope speed, and tension on the rope. The experiments also demonstrated the importance of having an elongated recorder trace and a properly trained and experienced operator to interpret overall results. A design of a rope and test procedures for use in laboratory evaluation of instruments have been recommended by the American Society for Testing and Materials Committee E07.07.10, Wire Rope Applications. The USBM is working through this committee to develop standards for an electro-magnetic method of wire rope inspection.

Jan 1, 2010

By M. H. Kersten, G. A. Brady, Jerry W. Ramsey

Anthracite samples were oxidized with nitric acid to prepare products representing intermediate stages of oxidation . Similar oxidizing conditions affected different anthracites to varying degrees as characterized by peptization behavior with 0.1 N NaOH . Techniques used in attempts to separate and characterize the products included esterification , absorption spectrophotometry , sublimation , chromatography , electrophoresis , metal salt formation , and solvent extraction . Mellitic acid , either free or in the form of metallic salts , was identified in the acid- soluble products from 10 tests in which the anthracite was treated with nitric acid for periods varying from 24 to 1,000 hours . pentacarboxylic acid was also found in some products . Other benzene carboxylic acids were not present in amounts detectable by the methods used in this study . The acid- insoluble residue from nitric acid treatment varied significantly in solubility behavior toward different classes of solvents . The most effective ones tried included polar oxygenated solvents and pyridine . Infrared spectra of the extracted material indicated that similar compounds were extracted by the different solvents . Aliphatic amines and aniline peptized the residue and o- toluidine reacted with it . Organic material separated from the residue by peptization with dimethylformamide contained 1 percent ash , consisting of more than 50 percent zirconium .

Jan 1, 1964

By Christopher Mark

This proceedings volume contains papers presented at technology transfer seminars sponsored by the National Institute for Occupational Safety and Health (NIOSH) on New Technology for Ground Control in Retreat Mining. The seminars were conducted at five locations: Uniontown, PA (March 26, 1997), Norton, VA (April 8, 1997), Pikeville, KY (April 10, 1997), Charleston, WV (April 17, 1997), and Evansville, IN (April 22, 1997). The papers presented here describe several new, highly practical technologies developed by the NIOSH Pittsburgh and Spokane Research Centers3 to improve safety during pillar retreat operations. Two central issues are addressed: pillar design and mobile roof supports (MRS's). Proper pillar sizing is essential for safe pillar extraction. The Analysis of Retreat Mining Pillar Stability (ARMPS) program and its large data base of actual mining case histories are presented. LAMODEL, a second computer program, can be used for analysis of multiple-seam and other complex mining situations. Other papers address pillar design to avoid massive pillar collapses and the proper role of coal strength testing. MRS's have greatly improved safety where they are used for pillar line support. We studied the application of MRS's at 20 mines throughout the Eastern United States. Conclusions regarding the most effective section layouts, cut sequences, and support placements are reported. Field and laboratory tests of MRS's are also described.

Jan 1, 1997