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By R. Newman

An inexpensive slow-speed data acquisition system has been adapted to digitally record multiple parameters simultaneously at intervals of 15 seconds. The system was built for use with standard soils testing equipment to automatically record load and displacement parameters at predetermined instants in time. Simultaneous readout is achieved by the use of special signal conditioner and sample-and-hold circuits which read the multiple signals simultaneously and hold them until the slow acting system can print out. Three channels of a 10-channel system have been converted and found to operate successfully during a series of direct shear tests. A unique feature of the system, which significantly reduced its cost, is the power supply units. Dummy circuits are used to maintain a constant power demand during sampling) thus eliminating the need for a costly power supply with rapid response characteristics. The entire system, having an overall accuracy of 0.25 percent, was put in operation for a cost under $2,500.

Jan 1, 1970

By Clinton C. Knox

To demonstrate the feasibility of unwatering ore reserves previously indicated in the virgin Melrose zinc-lead field in Kansas and Oklahoma, the Bureau of Mines .carried through a pumping project on the Park Walton farm in 1943. Due to success of the undertaking, attention was turned to exploration of other indicated ore deposits and promising areas within that part of the field benefited by .the drainage project, By the middle of 1946, four private mining companies were active in the field; and a considerable output of lead and zinc concentrate had been obtained from the new Park Walton mine and mill. The Park Walton Ore deposit was unwatered by installing deep-well pumps in three holes previously drilled by the lessee. Pumping was continued by the Bureau of Mines at a rate of 2,500 to 1,000 g.p.m. for about 6 months; during this time the local static artesian water-level, originally averaging 108 feet below the surface in the old drill holes was lowered to the 316-foot level, which justified beginning the initial shaft sinking and mine developments. In all, about 750,000,000 gallons of water was pumped by the Bureau of Mines at an operating cost averaging $0.024 per 1,000 gallons.

Jan 1, 1948

By Jerry E. Olson

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 20,071-acre South Fork Wilderness Study Area (OR-005-033) and part of the 8,791-acre Sand Hollow Wilderness Study Area (OR-005-034) in order to evaluate their identified mineral resources. The study areas are located in Crook County, OR, about 58 air miles east from Bend. The areas studied are underlain by Tertiary- and Quaternary-age volcanic and tuffaceous sedimentary rocks. No mineral resources were identified in or adjacent to the study area. Except for common opal and agate occurrences along the northern boundary of the study areas, no mines, prospects, or mineralized zones occur within the study areas. Bentonite is periodically mined less than 1 mi southwest of the Sand Hollow study area boundary. Neither of the study areas has geothermal leases, but both areas are under lease for oil and gas.

Jan 1, 1987

By Laxman S. Sundae

A Bureau of Mines investigation was conducted to determine the effect of specimen volume on the apparent tensile strength of disks of St. Cloud Gray Granodiorite, Lithonia granite, and Rockville granite. The investigation used a technique developed by the Bureau to determine apparent tensile strength. Because the test specimens were selected without macroscopic defects, that is, cracks, joints, and planes of weakness, the strength variations are solely due to microscopic features. Several replications of each test were performed. Data for each set of specimens were fitted to a power law of the form y = axb, where y = apparent tensile strength, x = specimen volume, and a and b are constants. This power law is essentially a form of Weibull's theory. The average coefficients of correlation for St. Cloud Gray Granodiorite, Lithonia granite, and Rockville granite were 0.85, 0.53, and 0.78, respecitvely. In all cases a decrease in strength with increasing volume was noted; in the extreme case, a decrease of 40 pct was noted with an elevenfold increase in volume. The decrease in strength with increasing specimen volume is explained in terms of Weibull's theory.

Jan 1, 1974

By Frank S. Wartman

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Jan 1, 1927

By John C. Feeley

The methods used and the funds available for the development and oper- ation of shall mines and the reopening of small abandoned mines frequently present problems that tax the ingenuity and resourcefulness of the mining engineer far beyond that required in the mass production from large deposits. The objective of this paper is to describe in considerable detail the means whereby engineers have solved local problems in reopening an abandoned mine at which equipment, facilities, and funds were limited... The Etowah Coal & Iron Co. Gadsden red-iron-ore mine at Gadsden, Ala., 18 of interest in this category since it is the only independent red-ore mine under active development in the State. All other red-ore mines in Alabama are owned or controlled by the large iron or steel companies. The The mine, located on the southwest end of Shinbone Ridge in the outskirts of Gadsden lies in an ares once productive. but now idle, for many years. ore is relatively highgrade compared with that in the Birmingham area, but the bed is thin and somewhat lenticular. The presence of a large blast furnace at Alabama City, 3 miles from Gadsden, and the growing scarcity of red-iron ore supplies for it offered inducements for reopening the mine in 1946. Up to the time this circular was prepared (1947) only a small quantity of ore (about 1,500 tons) has been produced and shipped to the furnace. A force of 14 men was employed in sinking the main slope and developing a third "lift" (a local term for level) 100 feet below the old mine workings.

May 1, 1949

By R. A. Franks, G. F. Friel, J. C. Edwards, L. Yuan

Two mine-fire experiments were conducted in the National Institute for Occupational Safety and Health's (NIOSH) Safety Research Coal Mine (SRCM) at the Pittsburgh Research Laboratory (PRL) which demonstrated that smoke from diesel-fuel fires of 500 kW and 660 kW heat-release rates in a return airway can develop, without causing a complete air flow reversal, into a roof layer that can migrate upwind forming a counter flow to the primary airflow in a crosscut. Subsequently, smoke can penetrate into an intake airway and create a hazardous atmosphere in the intake airway upwind from the fire. Visibility conditions less than 13 m were created by the smoke in the intake airway downwind from the crosscut. Modeling of the event with a three-dimensional, time-dependent, computational fluid dynamics (CFD) program correctly represented the smoke movement.

Determine the advantages and operational limitations of water-let-assisted cutting used with mining equipment. Approach The Bureau of Mines con-ducted a research study to evaluate water-Jet-assisted cutting both in the laboratory and in underground mines. Earlier research on water-jet-assist was limited to laboratory studies where bit speeds and penetration depths were very low and large cutting force reductions were reported. For the past years, research by the Bureau of Mines and others has been concerned with the application of water-jet-assisted cutting under more realistic mining conditions. Study Results Water-jet-assisted cutting employs a mechanical cut-ting bit combined with a moderate to high-pressure water jet directed just in front of the bit tip to assist in the cutting process. Recent Bureau findings show that the addition of the water jet to the cutting bit can improve cutting in harder materials, significantly reduce respirable dust and bit wear, and increase product size. Some of these findings are presented as follows.

Jan 1, 1987

By C. H. Herty

As the problem of inclusions in steel has become increasingly important, more and more attention has been paid to the source of the oxide inclusions in steel. In killed steels the oxide inclusions are traceable to the reaction of deoxidizers with the iron oxide dissolved in the steel during the refining period of the open-hearth heat. In a large class of steel known as "rimming steel" the action of the steel during solidification depends entirely on the gas evolved, and this evolution in turn is controlled by the amount of iron oxide in the liquid steel in the mold. It is therefore of great importance to be able to determine the amount of iron oxide dissolved in steel and to devise methods for the control of iron oxide in any class of steel. The object of the present investigation was to obtain a true value of the oxygen content of liquid steel. If the steel has not been deoxidized, the greater percentage of the oxygen is present as iron oxide in solution.

Jan 1, 1932

By Carlton E. Brown

Sand, which is used widely under the wheels of mine locomotives to prevent slipping, is an important source of silica dust breathed by some employees of certain mines, such as those having appreciable grades on haulageways. The sand, as received, contains dust, and other dust is produced by passage of wheels of the train over the sand. Dust is disseminated into the air by such means as handling during unloading, drying, transporting, underground, sprinkling on the rails, passage of trains over Sections where sand is being or has been used, and walking over deposits of sand (or the dust thereof) on the haulageway. The disseminated dust is inhaled not only by persons in the immediate vicinity but also by others to whom the contaminated air travels. The inhalation of this must should be prevented to eliminate any possibility of the material causing silicosis (sometimes referred to as miners' consumption, miners' asthma, miners' phthiris, or miners' lung) and defined by the American Public Health Association4/ as: A disease due to breathing air containing silica (Si02), characterized anatomically by generalized fibrotic changes and the development of miliary nodulation in both lungs, and clinically by shortness of breath, decreased chest expansion, lessened capacity for worm, absence of fever, increased susceptibility to tuberculosis (some or all of which symptoms may be present), and by characteristic X-ray finding.

Jan 1, 1944

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Jan 1, 1981

By Bryan Buchholz, N. Kumar Kittusamy

Previous studies indicate that operators of heavy construction equipment are afflicted by musculoskeletal injuries of the arms, shoulders, neck, and lower back. These injuries appear to be due to excessive periods of sitting (static posture), work intensity, whole-body vibration, high resistance levers, repetitive motions, and awkward postures. (2-5) Although numerous studies have shown an association between operation of heavy construction equipment and symptoms of musculoskeletal disorders, very little research has been performed that systematically characterizes operating engineers' exposure to ergonomic hazards. The objective of this study was to systematically characterize the ergonomic hazards associated with excavating operations. As such, the following were performed: (1) vibrations were measured at the operator/seat interface (X, Y, and Z axes), and at the floor of the cab (Z axis); (2) psychophysical ratings of whole-body vibration (WBV) level and overall seat design were obtained; and (3) postural assessments of the job were made. Methodology This study evaluated an inexperienced female operator performing excavation, utilizing two different pieces of equipment. The operator was 37 years old, 162 cm tall, and weighed 80 kg. She had approximately 15 hours of operation time (experience) on the equipment evaluated. The two pieces of equipment used were: a Case Super 580E (1986) backhoe/loader, and an Insley H-2000 excavator (1975) (see Figures 1 and 2). More evaluations were performed on the backhoe/loader than on the excavator. The following evaluations were performed on the Case equipment: 1) vibration levels at the seat and floor; 2) psychophysical ratings of the overall seat design and vibration levels (for the task duration, and for an 8 hour duration); and 3) postural assessments. For the Insley equipment, all of the evaluations were performed except vibration measurements. When the evaluations were conducted, the following environmental conditions were noted: the temperature was 31°F, and soil and terrain conditions were rough and frozen.

By James C. Fowler

As report covers the installation and testing of a permanent seismic monitor system at the Loveridge Mine in West Virginia. The testing of the system showed several things: 1. Getting the seismic data hack to the central computer in a usable form is possible 2. It is possible to detect small explosions. 3. The use of this system as a auxiliary system to detect hammer blows from miners trapped in the area of one of the geophones is possible.

Jan 1, 1974

By A. D. German

This paper presents one of a series of digests of foreign mining legis- lation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of tie laws of Ecuador has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State..

May 1, 1930

Objective To develop safety training tools for mine safety and health professionals that fill gaps in currently available materials. Background Over the past 4 years, NIOSH has developed and released a series of training videos targeted at underground mine safety. These videos were developed in close cooperation with the mining industry and safety training professionals and were intended to provide realistic, interesting, effective training to both new hires and experienced miners. The videos cover the mining cycle, starting with the breaking of the rock (Handling Explosives in Modern Mines), making certain the work area is safe after a blast (Rock Falls— Preventing Rock Fall Injuries in Underground Mines), installation of ground supports and recognition of failed supports (Miner Mike Saves the Day), and hauling both ore and materials in the mine (Hazards in Motion). A separate video (Hidden Scars) captures the story of a fatal rock burst through an interview with a miner who nearly died and who lost his partner in the accident. These videos have been extremely popular in the mining industry and are being used across the nation as well as in 18 other countries. Two of them, Rock Falls and Miner Mike Saves the Day, have won Alice Hamilton awards, NIOSH’s highest recognition for Excellence in Occupational Safety and Health, in the Educational Materials category. Approach A recently completed independent evaluation of the SRL mining videos identified five themes that mine safety trainers consider necessary for successful training materials: high quality, credibility, accurate content, effectiveness, and an engaging nature. All of the NIOSH videos were rated very high for each theme. Using these measures of effectiveness, a more difficult challenge has been undertaken. Much has been written in the mining industry about the coming turnover in employment. The average age of miners in the United States is approaching 50, and many of the “experts” will be leaving the industry as they reach retirement age. The mining industry, like many industries involving skilled labor, relies heavily on a master-apprentice relationship between new hires and older miners. New hands learn from experienced miners. Their learning falls into three primary categories—they learn what’s important to know, they learn how to do things correctly and safely, and they learn the culture.

Mar 1, 2002

By Don Belsher

Work on contract H0272007 is summarized for the period of 1 February 977 to 1 February 1978. The initial evaluation of two potential systems for the location of well casings, voids, and tunnels in coal are described. The pulse measurement equipment used for the evaluation of the antennas selected possible use with a pulse time domain system and an FM-CW system is described. A TEM horn antenna design potentially suitable for use with these systems is given. An operational comparative analysis between various antenna types is presented.

Jan 1, 1978

By Sara J. Davenport, Genevieve Morgis, J. J. Forbes

"This circular is part III of a series of papers reviewing the literature on air conditioning in mines, with particular reference to the health, safety, and efficiency of miners.4/ It deals with theoretical and practical methods of conditioning air in mines to correct or alleviate the health hazards described in parts I and II and discusses the results attained by some of the systems now in use in various-parts of the world.The principal conditions to be corrected or alleviated are the chemical qualities of mine air (especially when contaminated with toxic and noxious gases and dusts) and the physical qualities (abnormal mine temperatures and humidities) that emanate from various sources in underground workings. Air motion and barometric pressure are physical qualities also to be considered.From the standpoint of health, knowledge of the composition of the air, or atmosphere, in mines and other underground operations is of prime importance. Suitable control measures or plans of procedure to combat or eliminate the hazards from contaminants must be based upon accurate information obtained by the selection and use of proper methods of sampling and analyzing mine atmospheres (1).5/Conditioning air is one of the most essential factors to be considered in any underground workings, not only from the standpoint of health and safety but also with regard to efficiency and productivity. Without modern air-conditioning, the war's great demand upon the copper mines could hardly have been met, as the mechanical refrigeration cooled off sweltering holes in less than a month, whereas in the past it was standard practice to blow air through the tunnels for 3 years or so until they were cooled.This paper discusses methods of determining the chemical and physical qualities of mine air and their control. Briefly, the following points are presented:"

Oct 1, 1949

Provide the U.S. mining industry with technology for designing environmentally sound, low-cost in situ leach mining operations to produce copper from small, deep, and/or low-grade copper oxide deposits. Approach Investigate the feasibility of a new mining method--in situ leach mining-as an alternative to conventional mining for copper. Study fundamental leaching technology that will facilitate future commercial operations. Develop guidelines and procedures that will enable mine operators to design and evaluate in situ leach mining operations for any specific copper oxide deposit.

Jan 1, 1989

By C. J. Wilhelm

The Carthage field, in Pamela County, Tex., is one of the largest gas-condensate in respect to both areal extent and volume of recoverable gas in the United States. The field (shown in fig. 1) is approximately 25 miles long by 20 miles wide on a southwest to northeast axis and includes 306 producing wells as of July 1, 1948. 3 distinct reservoirs in the Rodessa and Sligo formations have been found in the Carthage area the two main producing zones being the Upper and Lower Pettit, less important production being found in the Hill zone. Although a small amount of commercial production has been obtained in the Travis Peak formation, it has not been included in this report. An engineering study has been made by Bureau of Mines engineers, with the ultimate objective of arriving at an estimate of the gas reserves, by application of the data made available by the operators in the Carthage field. During World War II the Bureau of Mines submitted a restricted petroleum-engineering report on the Carthage field to the Petroleum Administration for War, at which time (March 1944) the development consisted of only 19 producing wells, 7 of which were dual completions. Because of the restricted nature of the first report and the limited development at the time of writing, a more complete investigation and subsequent publication was considered advisable. Bureau of Mines engineers have made use of all available records such as electric logs, drilling-time logs, core descriptions and results of core analyses, well-completion records, and production data in developing this report.

Jan 1, 1950

By Harold L. Rhodes

The Bureau of Mines has developed a method for determining the H2S content in natural gas samples. A gas chromatograph with a flame photometric detector was used to analyze samples with H2S concentrations ranging from 5,000 ppm to a minimum detectable limit of 0.01 ppm. A mass spectrometer was used to analyze samples containing H2S in amounts greater than 5,000 ppm. Methods are presented for preparing containers for H2S samples and for preparing standards using partial pressure and weighed standard methods, Sample collection techniques are discussed, as are analytical results which illustrate the loss of H2S while in the sample container and provide a basis for evaluating containers used for sampling and standard preparation.

Jan 1, 1979