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By Robert T. Mann

This paper is one of a series being prepared for and published by the United States Bureau of Mines on the quarrying, crushing, and grinding of limestone for cement manufacture. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total coats. It is recognized that publication of total costs might in many instances cause embarrassment to individual producers, as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of J. B. Thoenen, mining engineer of the Bureau of Mines, in the preparation of this paper.

Jan 1, 1933

By Frank D. Lamb

Four samples of manganese-bearing material from the Aroostook County, Maine, deposits were tested at the Eastern Experiment Station of the Bureau of Mines at College Park, Md., to determine their amenability to beneficiation by ore-dressing methods. The samples represented material from the Maple Mountain-Hovey Mountain deposit, the Dudley farm, and the Burnham farm and contained 11 to 14 percent manganese. None of the tests produced appreciably enriched concentrates suitable for further treatment for the production of ferromanganese. The intimate association of the manganese minerals with iron and siliceous minerals requires extremely fine grinding to liberate the manganese minerals in these ores and prevents efficient concentration by physical means.

Jan 1, 1953

By Piyush K. Dutta

This report describes the design, development and manufacture of production stoper drills and results of their field tests, it is shown that underground stoper drill noise level can be reduced from 118 dBA to below 100 dBA by using these pneumatic drills. The design concept of these drills is a radical departure from the standard valved rifle bar type drill machine design to a drill featuring a valveless independent rotation system, use of an integral muffler and a shroud tube. Six drills were manufactured in a standard commercial drill manufacturing setup and organization. The design and production technology proved that commercially viable quiet drills can be made available for mine use.

Jan 1, 1983

By F. W. Horton

This paper covers the salient features of the occurrence and mining of sheet mica in the United States and the preparation of mica for market; presents the results of a study of the physical properties of domestic and foreign micas, which the author hopes may he of interest to every mica user, as it definitely answers many questions as to the suitability of various minas for particular purposes; and discusses mica-trade conditions and the future outlook for the domestic mica industry. ACKNOWLEDGMENTS The author takes pleasure in acknowledging his indebtedness to J. R. Thoenen, of the United Stator Bureau of Mines, under whose guidance the work reported herein was performed, and to Frank L. Hess, also of the Bureau, for information on the geological and mineralogical characteristics of mica-bearing pegmatites.

Jan 1, 1935

By L. M. Burman

The phase-boundary pressure required to maintain a natural hydrocarbon fluid in a single phase must be considered in planning the recovery of reservoir liquids by miscible-phase processes. The change in the phase-boundary pressure at reservoir temperature that results when a light component or a mixture of light components is added to a reservoir fluid is an especially important consideration. The cricondenbar pressure (maximum phase-boundary pressure) and the critical pressure are unique correlated pressures that have been utilized to calculate the change in phase-boundary pressure that may result when the composition of a reservoir liquid is altered by an additive. In this study one reservoir oil and three gas-condensate fluids are used as examples. Correlations pertaining to the critical and cricondenbar states in chapters 4 and 5 of Bureau of Mines Monograph 10 (3)5 were used to demonstrate how butane and lighter components added to these reservoir fluids affect their phase-boundary pressures.

Jan 1, 1962

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the fourteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned & name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled except the deep holes drilled to test geophysical anomalies. The locations of those holes are shown on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

In 2007, a total of 7,199 sand and gravel mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 ? Sand and gravel mines were the largest mining sector, comprising 48.4% of all mining operations. ? Sand and gravel mines were found throughout all 50 states and Puerto Rico.

Aug 1, 2009

According to contemporary psychophysical theory, the relationship between the strength of a perceived sensation (S) and the intensity of a physical stimulus (1) is best expressed by a power relationship.(1) S=kln (1) This psychophysical principle has been applied to many practical problems, including the development of scales or guidelines for effective temperature, loudness, brightness, and ratings of perceived exertion. Based on the results of a number of experiments using a variety of scaling methods and a number of different muscle groups, the pooled estimate of the exponent for muscular effort and force is 1.7.(2) When applying this principle to work situations, it is assumed that individuals are capable and willing to consistently identify a specified level of perceived sensation (S). For manual materials handling tasks, this specified level is usually the maximum acceptable weight or maximum acceptable force. These phrases are defined by the instructions given to the test subject:(3) You are to work on an incentive basis, working as hard as you can without straining yourself or becoming unusually tired, weakened, overheated, or out of breath. If the task involves lifting, the experiment measures the maximum acceptable weight of lift. Similarly, there are maximum acceptable weights for lowering and carrying. Such tests are isoinertial in nature; however, in contrast to the tests described in Chapter 3, they are typically used to test submaximal, repetitive handling capabilities. Data are also available for pushing and pulling. These are reported as maximum acceptable forces and include data for initial as well as sustained pulling or pushing. Why Use Psychophysical Methods? Snook identified several advantages and disadvantages to using psychophysical methods for determining maximum acceptable weights.(4) The advantages include: • Realistic simulation of industrial work (face validity); • Ability to study intermittent tasks (physiological steady state not required); • Results are consistent with the industrial engineering concept of "a fair day's work for a fair day's pay"; • Results are reproducible; and • Results appear to be related to low-back pain (content validity).

Jan 1, 1998

In 2007, a total of 2,030 coal mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Coal mines comprised 13.7% of all mining operations. ? Bituminous mines comprised 92.4% (n=1,875) and anthracite mines 7.6% (n=155) of coal mining operations. ? Approximately 72% of all coal mines were located in three states: Kentucky (28.4%), West Virginia (22.6%), and Pennsylvania (20.5%).

Aug 1, 2009

This Bureau of Mines report summarizes the research, development, and evaluation demonstrations conducted by the Bureau of Mines under the Health and Safety Act of 1969 to improve the means of notifying miners underground, who are away from their own phone, that they are being called.

Jan 1, 1977

The problem of separating the constituents of a mixed gas has assumed increasing importance to chemical technology during the last several decades. Metallurgical practice, dealing mostly with the application of gases as fuel, such as for the oxidation or reduction of ores, has not often confronted an important need for such separations. If theory occasionally has indicated advantages in the use of purified or separated gases, as for example the "dry" blast for the iron furnace or oxygen-enriched blast for a variety of smelting operations, the economics of the proposals has not often been satisfactory. It has seemed evident that the practice of the chemical plant was too expensive with regard to installation or material costs, or both, for the needs of the basic smelting industries and indeed was applicable commercially to metallurgical purposes only when the metals in question were especially valuable or pure. This bulletin deals with a new mechanical means of attacking the problem of separation. Although it is improbable that any one type of separation could hope to find universal application, the method described is to be regarded as an alternative to conventional means that has attractive possibilities in certain instances. It extends the number of methods previously available by one that has not before been applied commercially and that utilizes a well-known property of gases that never has received effective technologic attention.

Jan 1, 1940

By N. L. Wimmler

The chromite deposits along the Stillwater complex in Stillwater and Sweetgrass Counties, Mont., have at various times been studied and reported on by the Federal Geological Survey, the Montana Bureau of Mines and Geology, other Government agencies, and private interests, Several of the deposits were explored to a mall extent by the owners during the World War of 1914-17, but no production resulted. The importance of these deposits and the urgent necessity of developing large domestic sources of chromite were realized shortly before the beginning of the recent World War. These deposits were therefore investigated and developed by Government agencies and., as a result, now afford the largest known reserves of chromium in the United States. In 1939, under the authority of the Strategic Minerals Act, the Bureau of Mines and the Geological Survey made preliminary investigations of these deposits. As a result, the Bureau of Mines conducted an extensive program of trenching, diamond core drilling, and sampling. This work was begun in August 1939 and continued to April 1943. The Bureau of Mines also performed numerous metallurgical tests on the beneficiation of the chromite ores and concentrates and for the production of chromium metal there from. Research continues as a means toward utilizing these ores.

Jan 1, 1948

By David E. Nicholson

In a Bureau of Mines investigation of the dynamic compaction of mine hydraulic backfills, two basic forms of mechanical vibration inducers were used and compared for effectiveness of compaction. Internal compaction, using concrete probe vibrators of various sizes, and external compaction, using plate vibrators} were studied and evaluated for use in underground stopes. An aluminum plate, which was light and displaced sufficient volume to remain afloat in fluid fill, and a steel plate were both used in the external compaction tests. Efficiency of compaction was better in studies conducted with internal probe vibrators. Tests were conducted in an underground backfilled stope with three different-sized probe vibrators (2-, 4-, and 6-inch-diameter) to determine an approximate area of influence. Results showed the areas of influence to be approximately 3, 4, and 5 feet in diameter, respectively, for the three different probes. Physical properties of hydraulic slurries were determined; preferred grain-size distributions, water exudation properties, and water contents of hydraulic slurries are reported. The best compaction results were obtained with moderately well-graded, fully saturated backfills, with slow rates of water exudation, which were capable of remaining in a semifluid state during the compaction process.

Jan 1, 1967

By Joseph B. Cummings

"Occurrences of fluorite on the Packard property were first examined by an engineer3/ of the Bureau of Mines in July 1943 as the result of receipt of an application for an access road. In August of the same year the showings were examined by a geologist4/ of the Federal Geological Survey. The property was again examined by an engineer5/ of the Bureau of Mines in March 1944. This last examination resulted in a proposal that access be gained by construction of a truck trail and that the Bureau of Mines undertake to explore the fluorite showings.The truck trail was constructed by the Public Roads Administration, which began the work on February 17, 1945, and completed it 8 days later.The Bureau of Mines exploratory program was completed on May 16, 1945. It consisted of stripping overburden, trenching, test pitting, tunneling, sampling, and topographic mapping.In addition to being described in some detail, the extent of the work as well as results are shown in accompanying tables and figures.Mrs. Rhoda A. Packard, Mrs. Nora 1. Cline, and C. B. Pettingill, all of Tonto Basin, Ariz., own the property, which comprises four contiguous, unpatented lode mining claims recorded at Globe, Ariz., as the Walnut and the Bluebird 2, 3, and 4. The claims are situated in T. 6 N., R. 11 E., Gila County. David L. Roscoe of Tombstone, Ariz., holds a lease and option to purchase.Access to the property is by Highway 88 from Globe, 34 miles to Roosevelt, thence 24 miles by a graded county road along the west side of Roosevelt Lake to Tonto Basin. Here the Greenback Ranch road, constructed by the Forest Service and maintained by the county, crosses Tonto Creek and continues easterly to the foothills. The truck trail leaves the road 8.5 miles east of Tonto Basin and runs 2.5 miles in a southerly direction to the property. (Fig. 1.)The fluorite deposits lie in and along a small canyon in a rough, rocky area at an altitude of about 3,400 feet, Vegetation is scant and of the usual desert variety. The summer climate is dry and hot and the winter climate moderate. Rainfall at the Forest Service Station in Tonto Basin was 11.4 inches from May 1944 through March 1945."

May 1, 1946

By Sally A. Shoop

Thirty-seven blasts have been monitored using either three or four seismographs, at four coal strip mines and at a limestone quarry. Statistical analysis of the data shows that square-root, cube-root, and site-specific scaling methods predict peak particle velocities with about the same (low) degree of reliability. Some mines have peak particle velocities that are significantly lower or higher than the U.S. Bureau of Mines averages (Siskind et al., 1980). This suggests that the option provided by the proposed regulations (Office of Surface Mining, 1983), to adjust blast designs based on site-specific measurements could be highly beneficial both to operators and to the public. The frequency spectra reveal that the predominant frequencies were generally less than 50 Hz but several blasts had a significant amount of energy up to 125 Hz. In some cases the vibration energy was concentrated at frequencies corresponding to the delay intervals.

Jan 1, 1983

By D. G. Willard

The U.S. Department of Interior, Bureau of Mines has evaluated the potential resource and annual availability of cobalt from 27 deposits or districts in 11 market-economy countries. More than 95 pct of primary cobalt production from market-economy countries, mainly byproduct output from copper and nickel operations, was analyzed. Approximately 1,200,000 mt of cobalt is potentially recoverable at the demonstrated resource level. Very large additional resources exist, especially in laterite deposits, but are at the inferred level. The producing operations evaluated in this study are expected to produce about 19,000 mt of cobalt in 1989, significantly less than the available capacity of about 31,000 mt. More than 14,000 mt per year of cobalt is produced from copper-cobalt deposits in Zaire and Zambia, of which 11,000 mt can be produced at a copper price of $O.60jlb or less with a O-pct discounted cash-flow rate of return (DCFROR). Approximately 4,400 mt of cobalt is produced annually from nickel-cobalt deposits in six countries, of which about 1,800 mt (in Canada and Brazil) could be produced at a nickel price of $1.50jlb or less at a D-pct DCFROR. Approximately 200 mt per year of cobalt is produced from a cobalt mine in Morocco. Most of the evaluated nonproducing operations and prospects that could potentially produce cobalt as a principal product or byproduct would require a total cost (including a 15 pct-DCFROR) significantly exceeding January, 1989 market prices of the principal commodities. Principal-commodity dependence, transportation routes, cobalt toxicity, and other issues that could affect the availability of cobalt are addressed herein.

Jan 1, 1991

By Eldon C. Pattee

THE BUREAU OF MINES began an investigation of tungsten resources of Montana in September 1953. This report presents information obtained from July 1955 to September 1957 on tungsten deposits in and near the Mount Torrey batholith. The batholith comprises part of the Pioneer Mountains of Beaverhead County in the southwest corner of Montana. Included in the report are assays and preliminary-examination data on 22 properties. Tungsten minerals are known to occur in 19 of the properties. The major producer is the Brown's Lake mine which has produced more than 625,000 tons of ore. Nearly all of the deposits are in the Lost Creek, Utopia, and Bald Mountain mining districts along the east and south margins of the Pioneer Mountains. The districts are less than 27 miles from Dillon, Mont.

Jan 1, 1960

By Chas. F. Jackson

This paper is published as a progress report for the first half of 1929 on the study of wining methods and costs in the Eastern and Central States. Data obtained from 25 mines using open-stope methods are correlated and summarized. Some of these mines have been described in considerable detail in reports already published as Information Circulars. In addition to the published reports on individual mines, considerable data have been obtained from other mines which were visited and studied during the course of the investigation. Many of these mines will later be described in detail in separate papers, and when the field has been covered in this manner it is planned to issue a bulletin on open-stops methods of mining which will amplify the subject matter of the present paper. Definition of ?Open-Stops?. - The term "open-stopes" as employed by the Bureau of Mines is applied to all naturally supported stopes; that is, stopes in which the excavated ore is not replaced by support of an artificial nature other than preps or stulls and in which the ore or (and) capping are not caved during the active life of the stopes.

Jan 1, 1931

By Carl Belser

This paper, covering Chaffee, Fremont, Gunnison, Lake, Larimer, Park, and Summit Counties, Colo., is the second of a series reporting on the tungsten potential of the Colorado region. The assembled information was obtained by examination of some properties, personal contacts with owners, and access to unpublished reports by other engineers. The tungsten-bearing areas of the 7 counties cover approximately 400 square miles and are in 10 distinct areas, which vary in size (fig. 1) from 1 square mile up to 290 square miles. The tungsten mineral wolframite was discovered by a man named Hackay near Dale on the Florence & Cripple Creek Railroad in the early 1900's, and wolframite and hubnerite were noted at Climax and the adjacent areas in Lake and Summit Counties at an early date, but no records of shipment from any of the areas are available before World War II. It is not known when scheelite was first discovered, but it was recognized in the Stockton mine during World War I. In the counties listed 64 properties are known to contain tungsten; of these, 18 have had some commercial output, although only 3 of them produced in 1953. The total production through 1953 is estimated at 115,000 short-ton units of tungsten trioxide. In 1953 by far the major portion came from the Climax mine.

Jan 1, 1956

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the ninth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township map. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948