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By Malcolm J. McPherson

Observations of environmental parameters in mines have traditionally been made by means of hand-held instruments, these being employed as a basis to ensure that atmospheric conditions in the mine remain within limits commensurate with safety, to safeguard the health of personnel, and to ensure that statutory requirements are met. Thus, starting from the first flame safety lamps of the early nineteenth century, numerous portable instruments have been devised over the years to indicate levels of dust, temperature, humidity, and concentrations of gases including oxygen, methane, and carbon monoxide. Similarly, portable instruments have been used to measure air velocity and pressure. For routine monitoring purposes, hand-held equipment suffers from many disadvantages. Readings are intermittent, often with long delays between successive observations, making short-term trend analysis impossible. Portable instruments are more liable to damage; they are labor intensive and provide a very limited amount of information either for control or planning purposes. The 1960's and 1970's have seen an accelerated development of mine environmental monitoring equipment. Alarm methanometers to give localized audiovisual signals became more common. These were followed by a variety of instruments which gave local, then local/remote continuous records, particularly of methane concentration and airflow. More sophisticated transducers and transmission systems were developed allowing further parameters to be monitored. This led to a proliferation of paper strip and chart recorders which had to be maintained and inspected regularly for trends and abnormalities.

Jan 1, 1979

By P. Somasundaran, F. F. Aplan

The Formative Years Douglas Winston Fuerstenau was born December 6, 1928 in Hazel, SD to Edwin Arnold and Hazel Pauline (Karterud) Fuerstenau. His father, of German extraction, was a farmer and, later, a cabinet maker, while his mother, of Norwegian lineage, was a school teacher. His parents are still alive today at ages 91 and 88, respectively. Two younger brothers, Richard and Maurice and a sister, Jean, completed the family. The family first lived near Watertown and later in Lemmon and Mobridge, SD. The 1930's were a difficult period for any family in South Dakota. A decade-long drought made this a part of the dust bowl, which together with a serious infestation of grasshoppers (the locust plague described in The Bible), and the world-wide depression, made living difficult for all. In spite of these privations, Doug has many happy memories of his childhood which can be attributed to the resilience of youth and a strong family structure. He has fond memories of summers spent with his cousins on family farms where the children were introduced to farm chores at an early age. When he was old enough, he worked in a grocery store after school. At the age of 14 he spent the summer hearding 2,000 sheep near Lemmon, SD as his contribution to the war effort in that labor-short period. He remembers well the dust storms of the 1930ts, the destruction at his grandmother's farm by tornado, pulling weeds on the farm, threshing grain with a monstrous steam-driven machine and such pleasant childhood activi- ties as fishing for bullheads, hunting for rabbits, searching for arrowheads in newly plowed fields, and ice skating in the winter. Early in life his parents instilled in him a strong work ethic, a love of learning and the need for a good education. In 1943, the family moved to Rapid City, SD. With a population of 13,000, it was

Jan 1, 1989

By E. D. Attanasi

The US mining industry finished the traumatic 1980s with a strong economic performance. Worldwide economic growth and capital spending led to tight metal markets. So, 1989 metals prices were generally higher than average 1988 prices. Financial markets' volatility resulted from US junk bond defaults, heavy US savings and loan losses and effects on the US budget deficit, higher energy prices, and the seemingly intractable problems of some debtor countries. Moreover, the events in Eastern Europe promise fundamental changes in the world economic system for the 1990s. US mining companies that survived the decade had weathered economic changes that, at one point, reduced industry employment by 40%, drove oil companies to divest or liquidate recently acquired mineral subsidiaries, and led to substantial write-offs of reserves. Canadian and other international minerals firms experienced similar industry upheavels. The forced modernization and capacity rationalization produced an internationally competitive US industry. For example, even though 1989 US copper production was 27% greater than in 1980, industry employment was less than half the 1980 level. The steel industry and other minerals industries showed similar productivity improvements.

Jan 1, 1990

By Robert A. Haney, David J. Atchison, Kenneth G. Fields

Mining systems with greater than a 20-foot face advance (deep cut) have become popular due to their increased productivity and safety. The face dust collection system used in many of the mines employing the deep cut systems, incorporates a machine mounted dust collector with either a blowing or exhausting line brattice and a remote control operated continuous miner. In order to characterize and quantify the parameters used to control dust with these systems, the Dust Division conducted studies on four mining sections using continuous miners with deep cut mining systems. On each section, the dust control system incorporated line brattice with a machine mounted dust collector. The remote control made it possible for the continuous mining machine to advance further while permitting the operator to remain under supported roof and away from dust generated during mining. The purpose of these studies was to evaluate the effectiveness of deep cut mining systems using dust collectors to control respirable dust exposure. This paper summarizes the results of the studies conducted. At each mine face workers were sampled to determine their full-shift dust exposure. Additionally, fixed point dust samples were collected at various locations to determine relative concentrations of dust generated from mining. Air quantities were measured at each working place to determine the amount of air delivered to the face area. Evaluations were made by comparing worker exposures to respirable dust samples taken at appropriate locations upstream and downstream of the coal faced being mined. An estimate of the amount of the respirable dust being generated at the face during mining and the amount of respirable dust being removed by the dust collectors was made by balancing the air quantities and the dust concentrations immediately upstream and downstream of the coal face. Results of the studies showed that the dust control systems, were effective for controlling workers exposure to respirable dust. Dust collector efficiencies were determined to be approximately 85 percent. While the dust collectors were effective in removing respirable dust, the success of the systems with line brattice greater than twenty feet from the face, was dependent on the use of the remote control which permitted the continuous miner operator to remain out of the high concentration dust cloud in the working face. Dilution from intake air, combined with the dust collector efficiency, maintained exposure of other section workers below applicable standards.

Jan 1, 1991

By T. Negeri, Y. Breau, M. Plante, A. Orumwense

As part of a joint project on fine particle processing, sponsored by the Consortium de Recherche Minérale (COREM), Natural Resources Canada (NRCan) and Hydro-Quebec, two flotation plant circuits were sampled to identify and quantify the causes of mineral losses within several particle size ranges. Size distributions, size-by-size assays and global chemical assays (Cu, Zn, Fe, S) were determined for the major streams. Size distributions were measured in 13 classes by sieving, cyclo sizing (-45 µm), and laser beam diffraction analysis. BILMAT, a material balance computation software package, was used to optimise the sampling, to estimate the unmeasured variables, and to assess and improve the quality of the information generated. The methodology has been extended to correct cyclo sizer data and reduce discontinuities of up to 20% at the transition from sieves to cyclo sizer. The paper describes the methodology and the main conclusions emerging from material inventory of the flow sheets.

Jan 1, 2003

By Henry G. Healy

Observation well (Hydrographs are shown for these selected wells) Contour represents the height, in feet referred to mean sea level, to which water would have risen in tightly cased wells that penetrate the major water- bearing formations in the Floridan aquifer, July 6-17, 1961. Contour interval 10 and 20 feet, changing at mean sea level. [ ] Extent and distribution of flow areas vary with fluctuations of the piezometric surface, particularly in areas of heavy Relatively small areas of artesian flow are not included immediately adjacent to and paralleling the coast and many of the major rivers and springs

Jan 1, 1966

The successful exploration for Austin Taylor and Gen. McRae from 1931 to 1940 obscured the fact that I was reaching a period of transition. This was true both in personal and business life. It was probably fortunate that I did not realize how great a change must come after I passed the age of 50. In the personal life of our family the change came when both our children left home to go to school or college. This made home a different place and, because of the absence of the children, Dorothy could devote much of her time and attention to the art she loved so well. She could spend long periods in New York, the center of the nation's art life. Vacations at Tahoe and long pleasure trips made the separation from the children less disturbing but it could never again be the same as it had been in the first 20 years of our marriage. The change In my business life was just as complete, though a little more gradual. While work for Bralorne and General McRae made the "bite" of the Great Depression less painful for us than it was for most consultants and their families, the fact that I was getting older made a new sort of work inevitable. I was 50 years old and the total grew rapidly. Planes and automobiles that made travel easier even in the wilds of Alaska and northern Canada still made it possible for me to look at new prospects, but increasingly often I was exhausted at the end of a day's climb and, if the nature of my work did not change there would soon be no more work. Fortunately work of a new sort came a little at a time. As I became a director of Bralorne and president of its American subsidiaries I had to take on more administrative work, and success of these operations made others want to employ me to help direct policy and value mines. I was also asked to arbitrate contests between mines when technical disagreements were so great that judges or juries could obviously not understand them My consulting for government agencies helped to

Jan 1, 1976

By Eduardo Poltronieri Trés, Anderson Denadai Thomazini, Rodrigo Boyer Fernandes, Francisco de Assis Dutra Macedo, Gilvandro Bueno, Maycon Athayde, Rossano Augusto Pilon Nunes

The earliest industrial application of high pressure grinding rolls (HPGR) at comminution was in 1984 in the cement industry. Since then, the equipment has been widely applied in mining activities. Despite the rapid spread across the industry, several challenges are still present in the equipment’s application, especially considering the complex ore breakage behaviour reported for this process. The pellet feed’s HPGR comminution was recognized as fundamental to efficiently increase the particle surface area (e.g., blaine specific area, BSA) at a lower energy and water consumption level (Chapman et al. in J Southern Afr Instit Mining Metall 113:407–413, 2013). The present study considers a novel milling process applying only HPGR as a re-regrind stage after concentration. The amount of successive ground product recirculation into the machine to achieve the required particle size for the pelletizing process was investigated. The study compared the ball wet milling process with the innovative processing technology for hematite–goethite ores. Green pellet balling and induration processes were simulated in bench and pilot scale. The milling results showed a considerably steep increase in BSA after each recirculation step into the HPGR, although compared with the ball-milled product the size fraction <45 μm% increased a modest five percentage points after three recirculation cycles, remaining steady until the last recirculation step. As a result, the green pellet generated presented higher concentration of pellets between 10 and 16 mm (%10-16 mm), with a higher drop number than typically observed when produced with ball-milled feedstock. Consequently, on the induration process, a higher pellet deformation was observed during the pot grate loading. Despite that, the fired pellets still presented an outstanding performance in cold crush strength (CSS) considered suitable to an industrial application.

I reached New York at the start of my second South American adventure on Jan. 9, 1916. In the Anaconda office I found that we were not to take the steamer for two weeks which gave me time to study reports on Potrerillos and Corocoro. Reno Sales, whom I had met in Butte only casually, was to go with us to South America. Though he was only a little older than I, he was already an unquestioned leader of our profession, and we became and remained good friends. William Braden was in New York and would return to Santiago with us. Tom Hamilton would also be returning from a vacation. Leighton Stewart, a young engineer who was to work for Braden, was going on the steamer with us, taking along his wife. And of course Dr. Ricketts would go along. He had just become engaged to John Greenway&apos;s half sister, Kate Greenway, and in order not to be away from her longer than was necessary, he did not reach New York until a day before we sailed. This made eight of us who would be in the party. We were to go to Corocoro first, as Braden had taken an option on the Chilean company there. Development was already under way. As reports came in by mail we tried to get as good an idea of the property as we could before the actual examination. Mr. Thayer "put us up" at India House, one of the best lunch clubs in New York, and Reno and I ate our lunches there almost every day. Thayer, Braden, and Cornelius Kelley, who was to succeed Mr. Ryan as president of Anaconda, joined us when they could. At the lunches they told us about the under- ground war in Butte a few years earlier. When I wrote my chapter on the Butte wars in Romantic Copper more than 15 years later I could not help being biased a bit by my friends, all of whom were on the Anaconda side. But their opponents in the Clark and Heinze camp were just as biased in their comments on my book.

Jan 1, 1976

By Dennis K. Mortensen

Improvements in flotation technology are continually being made in the attempt to achieve the mineral processor&apos;s goal of maximum mineral concentrate grade and recovery at zero cost. Technology that cannot be totally proven in the laboratory must be tested under plant conditions either in a pilot plant or in the existing circuit. Problems associated with new technology can be solved effectively by the mineral processor who approaches each of the problems objectively.

Jan 1, 1989

By Michael Elliot-Jones

The fundamental competitive structure in world coal markets will be modified by the entry of such new participants as Colombia and the newer mines in South Africa. The US will, in most markets remain the swing producer, although a number of low cost US mines will continue to compete in world markets. Exchange rate swings will persist as a major hazard for coal exporters.

Jan 1, 1986

By Ed H. Wipf, Kurt L. Bryan, O&apos

Flow sheets employing SAG Mills as the initial stage of grinding are commonly selected for comminution of ores. Several alternative technologies are available. The paper will provide a brief review of the latest alternatives to SAG mills. Included in this review will be a discussion of the comparable benefits of each technology. Commonly accepted disadvantages will also be presented.

Jan 1, 1998

By S. P. Singh

To understand the intricate nature of blast damage and counter the associated problems, small-scale blasting experiments were performed on hydrostone blocks. Tests were then conducted during a drifting operation in a quartzite quarry. Blast damage was assessed by different techniques. On the basis of the experimental results, the effects of the energy partitioning characteristics of explosives on the damage were identified.

Jan 1, 1993

By C. Ostrowski, Z. Fajklewicz, K. Jakiel

Results of the application of the micro-gravity method in predicting rock bursts and rock mass deformations are discussed. Research was done in the Daisy black coal mine, Upper Silesia, Poland, during 1979-1980. At that time, microgravity investigations helped increase the safety of coalbed exploitation in progress. During the first stage of exploitation, a mining shock of 107 J energy was predicted in a region where 40 miners worked.

Jan 1, 1987

By Maurice Deul

Limestone can be used effectively in treating acid mine water. Aside from a lower cost than for other treatment agents, limestone has the advantages of easy storage and effectiveness even when impure and in slack sizes. Limestone incorporated into waste piles in layers or as riprap can inhibit acid formation; limestone rubble packed in a mine entry offers promise in formation of a low-cost autogenous resilient seal.

Jan 1, 1974

By B. J. Swenty, J. L. Hubbard, R. L. Peyton

Based on the results of the National Program of Inspection of Nonfederal Dams conducted by the US Army Corps of Engineers during 1977-1981, Missouri was found to have the highest number of "unsafe" dams in the nation. Many of the dams classified as unsafe in Missouri were tailings dams.

Jan 1, 1987

By K. N. Han, M. C. Fuerstenau

Challenges in five major areas of hydrometallurgy are presented and discussed. These are: leaching low-grade oxide and sulfide ores; oxidative leaching of sulfide concentrates; processing refractory ores; bacterial leaching and processing: and secondary metal recovery.

Jan 1, 1989

By H. J. Sohn, S. G. Doo

A systematic study was carried out to investigate the reduction reaction mechanism of oxygen on pyrite surface using electrochemical techniques. The polarization curves showed two distinct regions, the Tafel region for superoxide formation and limiting current region for diffusion of dissolved oxygen to form hydrogen peroxide. These results were confirmed with a-c impedance measurements.

Jan 1, 1990

By Paolo Massacci, Marco de Nardis

SPL (Spent Pot Linings) are hazardous waste. The described work seeks to identify simple and inexpensive processes for recovering the recyclable materials and thereby both reduce the volume to be handed to the dumps and produce a waste that belongs to a less dangerous class. For this purpose a study was conducted to characterise the structure of the cell and the refilling elements at the end of the Aluminum process. The properties of the material that make up the SPLs were determined in order to apply the related selection procedures. The study permitted the design of treatment process able to reduce the negative environment impact of the aluminum production cycle.

Jan 1, 1995

By H. Bogart

The Golden Sunlight Underground Mine located near Whitehall, Montana was portalled from the bottom of the existing Golden Sunlight Pit in July 2002. Gold was mined by sublevel stoping in the larger ore zones and longhole back stoping in the narrower ore zones. The stopes varied from 30 feet to 100 feet in width, extended up to 200 feet in height, and were completely unsupported. Underground production averaged 1,500 tons per day with a staff of35 people. The mine operated with a break-even cut-off grade of0.080 ounces per ton.

Jan 1, 2004