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By John Carr

The tremendous growth in grinding mill size and horsepower during the '70s demanded advancements in gear cutting technology and equipment for the '80s. Computers are used as an aid in the design and selection of the mill drive system; sophisticated computer graphics are used to create manufacturing drawings; and a new generation of gear cutting machines are used to manufacture the gears. These new gear cutters can generate-cut gears over 40' (12.2 m) in diameter at an AGMA quality level exceeding the currenty acceptable standards. The precision of the resulting gear assures maximum tooth contact, which will result in longer gear set life.

Jan 1, 1981

By Arthur W. T. Grimley

Hydraulic coal mining is being successfully practiced in China, U.S.S.R., Japan and Canada and in each country, excepting Japan where suitable sites are not available, the system is being expanded to either existing conventional mines or new mines. Productivity levels and economics at these mines are in all cases better than the productivities achieved in conventional mines in the same general localities. In the U.S.S.R. face productivities approaching 50 tons per man shift have been reported while in Canada the latest statistics show average face area productivity levels are in the region of 200 tons per man shift production monitor. In the United States hydraulic mining has not been actively pursued to the same degree and consequently there are no full scale hydraulic coal mines in operation or construction. Because many of the coal measures in the Western U.S.A. are generally somewhat similar to those being successfully hydraulic mined in Western Canada and parts of Siberia it is realistic to believe that successful hydraulic mines can be designed and developed in the Western U.S.A. Particularly if the vast technological base that already exists is used to improve on other people's ideas, systems, methods and equipment.

Jan 1, 1983

By Edward P. Larsen

At our annual meeting in St, Louis, Mo. in February 1961, we presented a comprehensive paper (No. 61-B-22) on the subject of "Blending and Handling of Materials for Agglomeration". In that paper you will find a discussion on the difference between "blending" and "mixing". With regard to "blending" we brought out the facts of its usefulness for the preparation o materials in an agglomerated mass to attain controlled chemical and physical uniformity. "Mixing" was discredited as not being useful for the attainment of uniformity of any kind.

Jan 1, 1962

By Kraig W. Grubaugh

Rapid growth in the rate of surface mining for coal has caused many states to increase the rigor and complexity of their surface mining codes. The promulgation of Federal surface mining standards may cause those states containing Federal land to amend their codes also. Presented is an up-to-date review of these codes with tabular summaries that divide the codes into operative functions. These summaries will be of use to new operators, multiple-state operators, and state officials. Suggestions are made for industrial efforts to present workable and acceptable amendments to these codes.

Jan 1, 1977

By H. M. Thorne

Industrial shale-oil operations in North America and Europe predated the Drake discovery, but, since then, most have succumbed to competition from petroleum. However, the existence of enormous oil-shale resources in the Green River formation of Colorado, Utah and Wyoming [estimated at over a trillion bbl of shale oil in place] and the advancement of United States oil- shale technology by research and development programs of government and industry during the past 15 years point to a natural partnership of petroleum and oil shale to meet the accelerating energy demands of the future. The utilization of oil shale is not a question of limited petroleum supplies, but one of economics. Two factors are expected to improve the economic outlook for industrial shale oil production -- a rise in petroleum replacement cost and further advances in oil-shale technology.

Jan 1, 1963

By Frank A. Jerabek

Problems of mine backfilling and fill material deposited underground, the characteristics and relationship between the deposited fill material and overlying ground, and the practical applications and limitations of hydraulic backfilling as ground support are discussed. A great variety of materials ranging from coal washery refuse to concentrator tailings is used as hydraulic fill. Some materials will solidify and cement; others will resemble quicksand, Hydraulic fill as ground support is more efficient in inclined mine openings than in horizontal mine openings, where it cannot be placed tightly to the back. This and other deficiencies of hydraulic backfilling led to the development of pneumatic stowing. Research work in hydraulic backfilling at the Pennsylvania State University is also discussed. This research work includes the investigation of segregation in the discharged fill slurry, the quantity of solids escaping in the drain liquid, the relationship of escaping solids to slurry concentration and discharge rate, and the compressibility of fine fill material.

Jan 1, 1965

By Inoka E. Perera, Robert Hildebrandt, Gerrit V. R. Goodman, Krzysztof Cybulski, Zdzisław Dyduch, Michael J. Sapko, Marcia L. Harris

To prevent coal dust explosion propagations, rock dust needs to be lifted and suspended in the air with the coal dust during an explosion. The addition of anti-caking agents prevents caking of rock dust in the presence of water. Mining and rock dusting processes can frequently create alternating layers of rock dust and float coal dust on mine surfaces. For this test series, a thin layer of coal dust was distributed on top of a layer of either treated or non-treated rock dust in the Experimental Mine Barbara, Poland. The experimental results compare the effectiveness of treated and non-treated rock dusts to attenuate a propagating coal dust explosion initiated with either strong or weak methane explosions. Experimental results indicate that the treated rock dust performs better than non-treated rock dust in arresting a propagating explosion, especially in the presence of moisture.

Jan 20, 2020

By John P. Anderle

A tectonically disturbed sequence of Mississippian age evaporites expressing a 5 milligal negative gravity anomaly near Sussex in southeastern New Brunswick, Canada, was investigated by a program of drilling, geologic and geophysical work over the past 27 months. Seventeen of twenty-one drill holes have penetrated 10 to 140 feet of potash mineralization in a salt sequence underlying 2 000 to 3 000 feet of arenaceous, conformable red beds, also of Mississippian age. Bromine and borate studies, lithological characteristics and geophysics, have facilitated improved understanding of the salt structure. The salt sequence has been affected by f1owage which has resulted in both major and minor folding. In the more disturbed areas, the potash interval was extensively subterraneally eroded at the upper anhydrite-salt contact.

Jan 1, 1978

By J. Bickson, C. DeGennaro, J. Homer, M. Girman

Powered haulage and haul truck-related fatal accidents are among the most frequent at surface mines. Industry organizations developed guidance on accident scenarios to address haul truck and mobile equipment collision-related accidents. However, there is a need to investigate accident data to prioritize these scenarios and identify factors relevant to developing validation methods for collision warning/avoidance technologies and determining their capabilities and limitations. Standards and effective validation methods are necessary for improving system efficacy within mining operations and promoting industry adoption. To address these needs, researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated available powered-haulage and machinery-related fatal accident reports documented by the Mine Safety and Health Administration (MSHA). Their objective was to gain a perspective for informing the development of test protocols and validation methods through determining the most prevalent accident scenarios and related factors. Our findings afford insight for addressing the most prevalent haul truck scenarios and relevant factors within U.S. surface mining environments.

Mar 2, 2022

By J. Gibson

"INTRODUCTION As one of the most pressing and important political debates of this century, climate change has captured global attention and is forcing governments to take action towards decreasing GHG and carbon emission levels below what was previously thought to be necessary. With the ever-increasing price of diesel fuel accompanied by the popular topic of carbon taxes and greenhouse gas emissions, the mining industry is looking to industry specialists for assistance. The benefits of a no-idle policy reach far beyond carbon reduction and fuel savings, ranging from decreased maintenance to increased engine life. With products like battery powered A/C systems and diesel-fired heaters, going no-idle is easier today than ever before. With both systems being manufactured to withstand the harsh environments of the mining industry, the end user will see a seamless change from conventional, inefficient belt-driven systems to future, stand-alone mobile equipment HVAC. THE HISTORY OF GHGS AND CLIMATE CHANGE In 1896 Svante Arrhenius first claimed that the combustion of fossil fuels may eventually result in enhanced global warming, but not until 1955 did Gilbert Plass draw global attention to global warming by summarizing that adding carbon dioxide to the atmosphere would intercept infrared radiation and thus warm the earth. Then in the early 1960’s Charles Keeling developed modern technology to produce concentration curves for atmospheric CO2 (Figure 1). In 1988 the Intergovernmental Panel on Climate Change (IPCC) was founded by the United Nations after acknowledgement of a rising global annual temperature. The IPCC consists of over 2500 scientific and technical experts from more than 60 countries, and because climate change could not be solved by a single country, the Kyoto Protocol was negotiated in 1998 requiring all participating countries to reduce their GHG emissions by at least 5% from the 1990 levels. The Protocol was signed by 186 countries in 2001 (since then several countries have retreated from the agreement, including the United States)."

Jan 1, 2015

By Liaqat Ali, Robert Chapman, Asghar Ali, Mohammad Tahir Shah, Seema AnjumKhattak, Mohammad Farhan

Alluvial gold is abundant in the Quaternary deposits of the Kabul and Indus rivers in District Nowshera, Khyber Pakhtunkhwa, Pakistan. Understanding the provenance of alluvial gold using morphology and elemental composition could be helpful in developing an exploration strategy of regional benefit. Detailed morphological studies of gold grains revealed high flatness index values which are indicative of a distal source. Compositional studies of 58 gold grains using SEM and EMPA showed broadly similar Ag ranges (1– 15 wt%) for each sample and occasional Cu values in individual gold particles to 0.4 wt%.Whilst the Ag profile is not diagnostic, the Cu values are compatible with derivation from either porphyry systems or ultrabasic rocks. The complex geology of the drainage catchments could host gold mineralization of other styles, but larger sample suites would be required to refine the current interpretation to establish whether particles which are simple Au-Ag alloys could be derived fromorogenic or epithermal sources. This scoping study has demonstrated that the compositional and morphological studies of gold grains are useful in providing information regarding the nature and location of the source of placer gold in areas where there is limited information on the nature and location of in situ mineralization.

Oct 6, 2020

By Willard A. Murray

Investigations of underground coal gasification (UCG) have been actively pursued by the U.S. Department of Energy since the early 1970s; the Lawrence Livermore National Laboratory (LLNL) conducted its first field experiment in 1976. In conjunction with field and laboratory studies of the process of recovering energy in the form of combustible gases from the burning of coal deposits in situ, an extensive environmental program has been conducted at LLNL under the auspices of both the U.S Department of Energy and the U.S. Environmental Protection Agency. This program has focused on groundwater contamination and ground surface subsidence caused by UCG. The material presented in this paper is a summary of results from the environmental studies of UCG activities conducted by LLNL as described by Mead, et al. (1981) and supplemented by the author's experience with this program in 1980 and 1981. The following sections describe specific groundwater contamination and surf ace subsidence problems encountered during field experiments in northeastern Wyoming, and will discuss implications of preliminary findings from geohydrological investigations of a site in southwestern Washington. Finally, possible environmental control technologies that are most likely to be effective in mitigating environmental impacts are discussed.

Jan 1, 1982

By Brian G. White

The Coeur d'Alene Mining District of northern Idaho is remarkable for its number of large ore bodies and for the amount of its historical production of lead, zinc and silver (Fig. 1). Since veins were first discovered in 1884, more than 127 Mt (140 million st) of ore have been produced from narrow, high-grade veins. Mining continues at the Lucky Friday, Galena and Sunshine mines (Fig. 2). All have been in production for decades. At these mines, more efficient mining and exploration techniques have reduced costs while adding significant new reserves. Even the old Bunker Hill Mine, where ore was first found in 1875, continues operation on a limited basis, partly involving production of world-class pyromorphite specimens. Until recently, the Coeur Mine was also a profitable silver producer. Other large producers have included the Star-Morning, Hecla, Page, Standard-Mammoth, Hercules and Gold Hunter mines (Fig. 2). The first deposits were discovered by prospectors who spilled over from the Murray gold mining district, 24 km (15 miles) to the north. The Bunker Hill Mine was founded the year after the first veins were discovered. Bunker Hill has now operated for more than 100 years. Production includes 2.3 Mt (2.6 million st) of lead, 1.1 Mt (1.2 million st) of zinc and 4.1 kt (132 million oz) of silver. Total district production through 1996 (Springer, 1997) amounted to 7.3 Mt (8.1 million st) of lead, 3 Mt (3.3 million st) of zinc, and 34.5 kt (1.109 billion oz) of silver. This record establishes the district as the largest recorded producer of silver in the world, while also yielding major quantities of lead and zinc. Only Potosi, Bolivia, may have produced more silver, although records are unclear. Despite the district's longevity, historic production and current activity, the published literature on the district lags behind with regard to recent concepts of district geology. The most recent comprehensive US Geological Sur- vey (USGS) bulletins (Hobbs et al., 1965; Fryklund, 1964) are dated. Much research in the last half century has been short-lived or geographically restricted because the district is large and its geology is complex - and even this research tends to remain unpublished. Thus, it has been difficult for in- [ ]

Jan 1, 1998

By F. L. Jackson

The large scale transportation and storage of sulphur in the liquid state is a relatively new development, but is really only a logical extension of old mining and processing techniques, It is not known who the first person was to win a relatively pure sulphur from ore by melting, but this method was commercially used at least two hundred years ago in Sicily and is still in use today. The Frasch process of mining was invented over sixty years ago, and the development and improvement of-liquid sulphur pumping and handling techniques has paralleled the growth in the Frasch mining industry. During the last fifty years, improvements in the technology of using sulphur have included the premelting of sulphur prior to its being burned for acid production or conversion into CS2 and other compounds. Yet, until fairly recent times, sulphur produced as liquid has been solidified into large blocks at the producing point, broken down by blasting or with mechanical equipment, and shipped in bulk form as a solid.

Jan 1, 1962

By MOHAMED WAEL, ANASTASIA GOEVA, ABDULAZIZ TAWFEEQI, IHTISHAM TARIQ, S. M. ZAKIR HOSSAIN, NIAZ ALI KHAN, MUHAMMAD FAISAL IRFAN

Carbon capture and storage (CCS) is an attractive area of research in such fields as CO2 mineral carbonation, global warming and sustainable energy systems. In this study, carbonation efficiency for aqueous mineral carbonation (MC) was achieved through two steps,which include leaching of calciumfrom cement kiln dust (CKD) followed by the reaction of pure CO2 with the calcium hydroxide precipitates formed by the hydroxylation using NaOH. Response surface methodology (RSM) with a Box-Behnken design (BBD) was applied to optimize the calciumleaching yield,while the carbonation efficiency from CKD was assessed using RSMwith central composite design (CCD). Optimization of calcium leaching is highly important, as it is a rate-limiting reaction step in MC and also influences and enhances carbonation efficiency. Different parameters including acid concentration (HNO3), leaching temperature, leaching time, and dose of CKD sample were considered in order to optimize the maximum yield of Ca leaching from the CKD sample. In addition, different CO2 flow rates and temperatures were used as parameters for optimizing carbonation efficiency. Two quadratic regression models were developed for each process, i.e. calciumleaching and carbonation. For calcium leaching, a maximum of 98.55% calcium was extracted under the optimal set of acid concentration 4.13 M, 90 °C, 28 min leaching time, and 13.8 g of CKD sample. For carbonation, the maximum carbonation efficiency of 89.2% was achieved for a CO2 flow rate of 1163 cm3/min at 90 °C. Calcium leaching results indicate that the leaching yield was significantly affected by all the input parameters except leaching time. For carbonation, both factors affected the carbonation efficiency, with the effect temperature shown to be greater than that of the CO2 flow rate. Additionally, the predicted results agreed well with the experimental values for both calcium leaching and carbonation processes, with errors of less than 1% and 5%, respectively.

Jun 5, 2020

By C. Jardine

The concept of the system is to minimize costly unscheduled breakdowns of equipment by replacing components earlier than their "life" expectancy. Periodic unit services are scheduled according to pre-set constraints. Service sheets are generated by matching a job and component master listing based on assigned cyclic component lives. The system can provide accountability of all man-hours reported and history information can be selectively retrieved. By reducing unscheduled equipment shutdowns, this system allows for better utilization of manpower and an overall improvement in equipment reliability and availability.

Jan 1, 1979

By D. N. Trerice

The Electric Power Research Institute (EPRI) is sponsoring the construction and operation of a coal cleaning test facility at Homer City, Pennsylvania. The facility represents a major investment by the electric utility industry to advance the state of the art of conventional coal cleaning technology. The facility is unique in design and can process large quantities of coal in conventional flowsheet configurations, simulate full size plant conditions, and perform open and closed loop performance testing on conventional and advanced coal cleaning equipment. Computer operation will also be demonstrated. The facility objectives, initial complement, and operating plane are discussed as they relate to other coal cleaning projects at EPRI.

Jan 1, 1981

By William C. Larson

The Bureau of Mines, as a result of its contract research program, is developing a retractable core bit for the wireline drilling system (Retractable Sit System, No, H0272004). The prime contractor, Longyear Company, Minneapolis, Minnesota, and the subcontractor, Doerfer Division, Cedar Falls, Iowa, have designed, fabricated, and are currently field testing the in-hole retractable bit system. he objective of the program is to develop a minerals exploration core drilling system that allows retraction of a worn out bit and insertion of a new core bit, without pulling the drill rods out of the hole. To date, the results of the project are encouraging, and the retractable bit contract is currently in the last phase of a four-phase program, which is on schedule and under budget.

Jan 1, 1980

By William Connell

NFPA 502, Standard for Road Tunnels, Bridges and Other Limited Access Highways establishes minimum fire protection and fire life safety requirements for road tunnels, bridges and other roadways where access by emergency responders is physically limited. The 2008 edition of NFPA 502 represents the Technical Committee?s consensus of current best practice for fire protection and life safety requirements for road tunnels, bridges and similarly limited access highways. Research of national and international test programs, design guidelines and regulating standards was per-formed and considered in an effort to establish a singular, comprehensive document representing a recognized base threshold of fire safety in these type facilities. This paper provides an overview of the more significant revisions including the application of fixed fire suppression systems, guidance on tenable environment, protection of structure and dangerous goods transport.

Jan 1, 2008

By G. T. Lineberry

Horsepower requirement is recognized as a most important equipment characteristic. Other critical equipment characteristics will be isolated and analyzed by traditional operations research techniques, using off-highway trucks as an archetype. A computer search technique has been developed, employing various production and cost analyses. With this model, the optimum combination of horsepower, capacity, and velocity can be found, minimizing handling cost per ton. An example of the program's use and interpretation of its results will conclude the paper.

Jan 1, 1984