Search Documents

By P. E. Damon

An arsenal of isotopic techniques is avail-able that can date the full range of hydrothermal ore deposits. The following are prerequisites for ideal results: (1) Careful collection of samples that are related to the event in a field and process context; (2) Optical examination of the component selected for dating to be sure that it has not been altered; (3) Careful preparation of a pure component of the sample selected for dating; (4) Precise and accurate measurement; (5) Knowledgeable interpretation of the data with reference to decay systematics, properties of the component analyzed as well as the field context and thermochemical environment of the ore process.

Jan 1, 1992

By L. You

Theoretical and analytical analyses of three mitigative measures- plane fitting method, trenching, and tension cable led to the development of a total protection plan to eliminate or reduce damages to the residential structures subjected to surface movements caused by underground longwall mining. The protection plan was applied to twelve residential houses and two external garages. The success rate is overwhelming. This paper describes the methods employed for protection and results of those case studies.

Jan 1, 1986

By M. J. Gula, S. S. Xue, E. P. Horwitz

A study has been conducted to remove iron from sulfate solutions using Eichrom's Dipexo® extractant, P,P'-di(2ethylhexyl) methanediphosponic acid (H2DEH[MDP]). It is found that this extractant can effectively and selectively extract ferric ion from highly acidic solutions. Ninety-nine percent of the iron was extracted from a simulated feed solution in a single stage. The separation factor, Fe/Zn, was 106. Over 90% of the iron in a loaded organic can be recovered in an aqueous solution by reductive stripping. This paper presents the experimental results. A new process for iron removal using Dipex extractant is described and discussed.

Jan 1, 1999

Steady increases in longwall production have required operators to apply greater quantities of ventilating air in an effort to control and dilute respirable dust. Significant increases in shearer speeds necessitate that longwall supports also be advanced at a faster rate. Both of these factors may contribute to overall respirable dust levels on the longwall face because as supports are lowered and advanced, broken material falling from the top of the canopy is entrained directly into the air stream. To address this issue, the Pittsburgh Research Laboratory collected respirable dust samples from four longwall faces to characterize shield-generated dust. This paper investigates the influence of air velocity and shield advance rates on respirable dust levels. Also discussed are engineering controls currently used to reduce shield dust and alternative controls being investigated by the National Institute for Occupational Safety and Health (NIOSH).

Jan 4, 2010

By K. Yatsunami

NKK has developed a new cold bonded pellet process. The features of this process are; 1) it is a continuous process with 10 hours curing. 2) Products can be used as materials for various metallurgical furnaces. 3) Various kinds of slag are used as binders if necessary. 4) The quality of products is excellent. The pilot plant completed in 1981 is now being successfully operated. We are also constructing a commercial plant at our Niigata works. We produced cold pellets containing carbon as material for ferroalloys (Si-Mn), by pilot plant and used them in furnaces. Consequently, considerable economic advantages were obtained.

Jan 1, 1984

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept. 22, 2007 at the Charles F. Barber Pavilion (Museum Convention Center) in Leadville, CO. The four inductees are James Harold Courtright (1908-1986), Dr. Howard L. Hartman (1924-2002), Charles Washington Merrill (1869-1956) and Kenyon E. Richard (1915-1993). The inductions will bring to 197 the number of mining “greats” whose engraved photographs and biographical sketches are installed in the National Mining Hall of Fame.

Jan 1, 2007

By G. Deschenes, W. Yen

Ammonium thiosulphate is a non-cyanide lixiviant for gold leaching. The major problem is the high reagent consumption. A combination of 0.3M (NH4)2S2O3, 0.03M CuSO4, 3M NH3 was used to leach a copper-bearing gold ore at pH 10.2 for 24 hours. 30 kg/t of thiosulphate was consumed. Oxygen and copper species were found to be responsible for thiosulphate decomposition. The thiosulphate consumption could be reduced to around 17 kg/t by adding chelating agent, reducing copper sulphate concentration to 0.001 M and replacing CuSO4 by NiSO4. The increase of pulp density might reduce the thiosulphate consumption to around 17 kg/t. By regulating the oxygen supply, the thiosulphate consumption could be reduced to 10 kg/t.

Jan 1, 2002

By H. Savasci, G. Yarim, J. S. Chung

As part of ongoing deep-ocean mining research, hydraulic transport systems as well as status of deep-ocean mining systems are reviewed in the aspects of manganese nodules and crusts from 8006,000-m depth. The emphasis of the investigation of hydraulic transport is placed on the shape effect of particles on the pressure gradients and flowrates. Series of tests are being conducted to study the lift characteristics of a 2-phasevertically upward hydraulic transport of 2 types of small solid particles in a PVC pipe of 1-in (2.54 cm) diameter: irregular-shaped silica sands and equivalent spherical glass beads. Pressure drops and mass as well asvolumetric flow rates were measured by electromagnetic(EM) flowmeter and mass flowmeter. The particle sizes used are 8-10 mesh. The results in turbulent flow range of 101045Re show that pressure gradients or friction factors are smaller for the spherical beads than the sands. The larger the concentration of the particles are, the larger the pressure gradients become. The larger the particle concentration is, the less the effect of particle shape on pressure gradients becomes. The shape effect is greater for the minimum particle transport velocities than for the settling velocities.

Jan 1, 1999

By Steve Kral

The mining industry is no stranger to hard times. Throughout its history, the industry has faced the ups and downs of commodity prices, difficult-to-mine-and-process ore bodies, labor issues and other problems. Throughout it all, though, the mining industry continues to provide the materials needed for society —even in the face of attacks by those who seek to cripple the industry or have it go away. The reason the mining industry survives, of course, is that mankind requires the products the industry produces. And, in recent decades, the industry has developed new technologies and improved on existing ones to produce those products in environmentally sound ways. At the same time, the economic benefits have been enormous to communities throughout the world where mining takes place.

Jan 1, 2002

By R. L. Summers

The tremendous engineering advances occurring during this past century are very evident within the boundaries of the Anthracite Section of AIME. The Steelton plant of Bethlehem Steel Corporation, located along the Susquehanna River just east of the Commonwealth's capital at Harrisburg, for more than 105 years has experienced a most dynamic life which has paralleled America's industrial growth. (Figure 1) In June 1865, just after the Civil War, a group of men met to organize the Pennsylvania Steel Company. The war had brought into sharp focus the vital importance of the railroads to the country's expansion. Until that time wrought iron rails were used, and the replacing of track after only several months wear had become an almost unbearable cost. The spirit of free, competitive enterprise and the prospects of a lucrative market compelled these men to form that first Pennsylvania Steel Company and to develop better rail products. They issued the following statement: "...our desire to free ourselves from dependence upon a foreign market (has) led to the organization of the Pennsylvania Steel Company, and the parties who have connected themselves with it are determined to produce upon American soil all the principal manufactures of steel that are now, at such a serious cost for freight, commission, insurance, exchange, duty, etc., and often, with so much delay and uncertainty, imported from abroad. (We) are preparing to establish near the consumer, works at which articles of accustomed pattern will be promptly produced, and from the

Jan 1, 1971

By J. Parker

Gentlemen; Rainy day in Upper Michigan, a good time to catch up on reading. Am doing that, and have a couple of questions concerning the K and P paper on roof problems and supports. I wonder if the authors can enlighten me. The compressive strength of the coal was reported as 4.4 MPa (633 psi) and compressive stresses measured in the coal seam were reported at around 27.6 and 48.2 MPa (4000 and 7000 psi ). Can such a soft coal actually contain such a high level of stress? Can it be measured as if the material were elastic, or does the coal behave plastically? Can that stress level be confirmed with hydraulic load cells? And if the coal is so soft, and if it is plastic, why is the stress field not hydrostatic? The intact roofrock appears to be unusually strong, with compressive strength reported at around 145 MPa (21,000 psi), and some failures were noted as soon as the rock was exposed. Were tests run to find out how that rock responded to the addition

Jan 1, 1991

By J. Kretschmann, P. Goerke-Mallet, C. Melchers

Mining always leaves a mark behind. Dealing with this legacy is not only a tremendous challenge in Germany, but internationally too. The Technical University Georg Agricola (THGA) in Bochum, Germany, has established a Research Center for Post-Mining. Researchers combine expertise from a variety of technical and nontechnical fields in their quest to shape the post-mining era that completes the mine life cycle. In this respect, the Research Center focuses on four research areas: Perpetual tasks and mine water management, Geomonitoring, Material sciences and site transition. With more than 200 years of successful partnership with the mining industry in Germany and abroad, THGA offers a perfect setting for fresh and sound ideas in order support mining’s social license to operate. The aim of the paper is to describe the Post-Mining Research Center along with exemplary research projects that are of interest to the mining industry globally and to foster technical communication and research networking.

Mar 2, 2022

By J. Platt

Debate over acid rain legislation has presented a moving target for coal and utility company planners attempting to figure out how legislation will affect their business environment. In spite of disagreement among experts, the prospect for continued change, and persistent --perhaps even growing --uncertainty, a great deal has been learned about coal market dynamics. This paper reviews progress and describes some of the major problems and controversies.

Jan 1, 1990

By Frank P. Frandina

The Heartland Corridor Clearance Improvement Project is part of a regional Public-Private initiative to allow double stack container trains a direct route from the Port of Norfolk through Virginia, West Virginia, Eastern Kentucky and into Central Ohio. The project involves clearance improvements to twenty-eight tunnels, twenty-one of which require structural modification. With construction of the first Package of tunnels just underway at press time, this paper summarizes the program implementation from design through the initial stages of construction.

Jan 1, 2008

By J. F. Childs

"INTRODUCTION Comprehensive overviews of the world-class talc deposits and related prospects in Montana were published by Olson (1976) and by Berg (1979). Both of these compilations include detailed descriptions and maps of the talc deposits and occurrences and were followed by a regional map and summary descriptions of the talc deposits published by Van Gosen et al. (1998). More recent publications, descriptions and field guides for some of the deposits include Underwood et al. (2014), Cerino et al. (2007), and Cerino (2002). The present paper focuses on some of the more recent ideas regarding talc formation that have developed since the publication of the earlier overviews. Olson (1976) reported that talc production from the deposits in southwestern Montana was over 200,000 tons in 1974 and that talc production had doubled between 1969 and 1974. The last year for which the U.S. Geological Survey published production records for talc by state was 1993. Production in Montana in 1993 was 350,000 tonnes (Virta, 1994). Remaining reserves are substantial at all three of the producing mines in the district. Minerals Technologies Inc., the parent company of Barretts Minerals Inc., stated in its 2014 annual report that it has reserves of 2,791,000 tons of talc. Imerys stated in its financial report for 2014 that it had 19,638,000 tons of proven and probable talc reserves at its North American mines. Although the Imerys reserves were not reported by individual mines or states, a large proportion of the total reserves would likely consist of the reserves at the Yellowstone mine, located south of Ennis, Montana. Talc mined in southwestern Montana is of high purity and is the quality used in a wide variety of applications including paints, ceramics, plastics, rubber, coatings, agriculture, cosmetics, and pharmaceuticals. GEOLOGIC SYNOPSES FOR MAJOR MINES AND COMMENTS ON REGIONAL DISTRIBUTION OF TALC OCCURRENCES The general geology of southwestern Montana is shown in Figure 1along with the locations of the three producing talc deposits in the area and the extent of pre-Belt marbles that host all of the talc mines and prospects. The term “pre-Belt” is used in the present paper because zircon and other radiometric data developed in recent years indicates that the metamorphic rocks that form the crystalline basement for the middle Proterozoic Belt basin in the Dillon Tectonic Block of southwestern Montana includes both Archean and Paleoproterozoic rocks (O’Neill et al., 1996; Foster et al., 2006; McDonald et al., 2012). An envelope or “corridor” has been superimposed on the geology in Figure 1 which encompasses all of the talc deposits that have a significant resource. This “talc corridor” will be discussed in later sections of this report. The more important talc deposits are discussed in this report section."

Jan 1, 2016

By J. Hebert, J. Donnelli, J. Sedey

Installation of a Load Commutated Inverter (LCI) provides an economical method for conversion of a Fixed Speed Semi-Autogenous Grinding Mill into one with variable speed, qualities. Though capital intensive, the conversion appears to be one of the most cost-effective methods to gain the advantage of critical speed variations for variable ore characteristics. Expected advantages from the installation of LCI drives at the Goldstrike Mine were decreased liner wear, decreased media consumption and additional grind for increased production rates. These issues as well as construction, economics and performance will be discussed in the presentation. The utilization of the existing equipment came to play an integral part of the study and economic justification of the overall project.

Jan 1, 1999

By Brenda Myers-Bohlke, Tor L. Brekke

INTRODUCTION In recent years several cities in the Eastern United States have constructed subway systems in deeply weathered igneous and metamorphic rocks. Portions of these transit tunnels and shafts have penetrated zones of saprolite. The purpose of this paper is to define saprolite and discuss saprolite behavior in terms of construction and design of tunnels and shafts. Saprolites are products of in situ weathering of rock, with properties intermediate between those of soil and rock. A well-developed weathering profile can be divided into zones of residual soil, saprolite, transition zone materials, weathered rock, and fresh rock. Saprolites are distinguished by a high degree of weathering and by retention of parent rock textures and discontinuities. These structures persist as relict features because of iso-volumetric weathering (Cleaves, 1974) and formation of intergranular bonds that give cohesion to the saprolitic material. As saprolite continues to weather, the bonds are broken, causing the saprolite to decompose and disintegrate into a true residual soil mass without relict structure. Saprolites may form from igneous, metamorphic or sedimentary rocks, but are most easily recognized when derived from igneous and metamorphic rocks because of their inherent structures. The physical characteristics and properties of residual material vary as a function of mineralogic composition, structure, and discontinuities of its parent rock.

Jan 1, 1985

By Nelson Alonso Portal Ravichaua, Melissa Esther Mendoza Tirado, Raúl Arévalo Saavedra

This study analyzes the implementation of an integrated strategy for environmental education and community awareness in Cajamarca, Peru—an Andean region affected by climate variability and the public perception of miningrelated water shortages. In collaboration with the Interactive Water and Earth Museum and the Newmont ALAC Foundation, three-month campaigns were conducted in schools and local communities. Key topics included the water cycle, climate change, and water availability, linked to urban infrastructure projects that improved flow rates through strategically located tubular wells tapping underground aquifers. The initiative addressed the challenge of communication in a context where mining is often blamed for scarcity, fostering scientific understanding of contributing factors. The study highlights how science-based outreach and institutional collaboration can strengthen resilience and promote sustainable water stewardship in mining-influenced regions.

Feb 22, 2026

By Mark Laffoon

Gold Fields Operating Co.-Chimney Creek has conducted numerous ore reserve modeling studies In order to optimize the estimates of the gold grades and tonnage distributions. Improved models continue to be produced for the major pits which Increase confidence levels required by Gold Fields management and provide the basis for more accurate long and intermediate term mine planning. Various kriging and non-kriging estimation techniques are used at Gold Fields -Chimney Creek Mine. This paper reviews the modeling histories and, current procedures used to construct these models with particular emphasis on the North Pit deposit.

Jan 1, 1991

By Roshan B. Bhappu

Stimulated by current $0.80 to $1.20 per pound price tag of copper, considerable interest and activity have been generated in the copper mining camps throughout the world, and especially in the Southwestern United States and Northern Mexico copper belt. Under these economically favorable conditions, many of the marginal oxide-copper deposits, as well as newly discovered prospects, are under scrutiny for possible exploitation. For both the known deposits and new prospects, the big question facing the mine operator is the selection of the best method for processing these economically attractive oxide-copper deposits. Several variations of the hydrometallurgical processes are currently available for treating oxide-copper ores which can be mined by the open-pit method. Basically, these processes involve preparing the ore for application of an acid solution, applying the solution to the ore, and recovery of the metal from the pregnant solution. Dump leaching, heap leaching, vat leaching, agitation leaching and, in more recent times, in situ leaching or solution mining in combination with well established cementation process or the newly developed solvent extraction-electrowinning system have all been employed or have been investigated for the recovery of copper from oxide ores. Of these processes, dump, heap and vat leaching have been successfully practiced for treating oxide-copper ores. Agitation leaching is a relatively newcomer and has been adopted from the experiences of uranium and gold processing. Finally, the inplace leaching technique is the latest process to be suggested for possible treatment of oxide-copper ores.

Jan 1, 1974