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By G. Schriever, H. Thiel, E. J. Foell

A long-term, large-scale, disturbance-recolonization experiment with relevance to the environmental effects of deep seabed mining is described. The study is funded by the German government and was launched in the abyssal eastern tropical South Pacific Ocean in February-March, 1989. After obtaining pre-impact baseline environmental data, a 10.8 km2 (4.2 sq miles) circular area of seafloor was disturbed using a specially designed "plow-harrow" device. An initial post-impact sampling series was carried out immediately after disturbance followed by a second post-impact sampling series six months after the disturbance. Plans call for repeated visits to the site at two year intervals to monitor the anticipated slow recolonization process until the area is inhabited by a new, stabilized community.

Jan 1, 1993

By C. L. Coldren

Recently there has been much discussion of the use of pipelines for the long-distance transportation of solids. Many have come to recognize the economies inherent in pipeline transportation. The widespread movement of oil and gas at astonishingly low costs - a gallon of oil moves from Montana to New York for less than that for the delivery of a postcard - has spurred others to sturdy this mode of transportation. Most interested people are aware of the inherent advantages of pipelines - continuity and reliability of operations - low manpower requirements per ton mile - moderate capital costs per ton mile - low maintenance costs per ton mile - low operating costs per ton mile.

Jan 1, 1963

By Robert N. Morris

Ladies and Gentlemen: It is a distinct pleasure and honor to appear before you representing the railway industry as I do, but there is a much closer personal relationship. I am a graduate Mining Engineer and worked in the coal industry for 15 years prior to becoming a railroader only 4 ½ years ago. I have been a member of AIME most of my adult working life and am currently active in the Washington, D. C. Section. While having been in the railway industry only a short time, I have become involved during the recent period of innovation and development of the new railroad technique known as unit train service. I have had the privilege of helping to work out a number of unit train movements to both electric utility companies and to a major steel concern, handling coal from mines on the Southern Railway to the consuming plants. On Southern, our unit trains are all of what I shall describe as shuttle train operations whereas within the railroad industry today several types of service are characterized as unit train service and many don't offer comparable efficiencies.

Jan 1, 1968

By M. Albrecht

In the mining industry and particularly in the processing plants, we use some large and unusual equipment. Understanding what it is and what it does is important to good operations, but how do you teach a new employee. When I started out in this field, the information on the processing equipment was easy to come by. Equipment manufacturers readily supplied it; their salesmen, often engineers themselves, knew how important the availability of this information was. Old engineers used their notebooks to train the new engineers. Over time this has changed. Equipment manufacturers have changed hands or gone out of business, and often the older engineers are gone. As a start in reversing this, this presentation will be an introduction to sizing, selecting, and operation of some of this equipment, in particular gravity separating equipment. Major portions of this have been excerpted from A Mining Engineers Notebook: Mineral processing (2).

Feb 23, 2014

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence events induced by underground longwall coal mining operations can cause various disturbances to surface structures ranging from integrity and stability to functionality problems. Highway bridges, as a kind of special road construction that can only tolerate smaller movements and deformations than road pavements, are particularly susceptible to severe influence caused by subsidence-induced ground movements and deformations. However, based on accurate subsidence prediction and correct influence assessments, efficient and effective mitigation and remediation measures can be designed and implemented to ensure the continuous service of bridges, safety of the travelers and smooth mining operations. In this paper, based on the predicted final and dynamic surface movements and deformations, the techniques to assess subsidence influence on the integrity, stability and functionality of bridge structures (e.g., decks, beams, abutments, etc.) are presented. A number of mitigation measures to protect the bridge structures are recommended along with an actual application case.

By W. C. Brice

Minnesota's mineral resources are widespread and diverse (Figure 1). In addition to the nation's largest iron and manganese reserves, the state contains sizeable vanadium, copper, and nickel resources. Recently it has been determined that the proterozoic unconformities in Minnesota have a favorable potential for uranium deposits. Finally, major potential exists in Minnesota's archean greenstone belts for gold, silver, and copper-zinc massive sulfides. Many of the state's mineral resources have been found in environmentally sensitive areas. This is not surprising since the natural forces associated with the formation of mineral deposits are often the same processes that create unusual landforms. For example, much of the state's copper-nickel is found within and adjoining the Boundary Waters Canoe Area (BWCA) and Lake Superior. The history of mineral development on the Mesabi Iron Range has also created culturally sensitive areas. Early iron mining development required the workers to live close to their jobs, and mine wastes were dumped as near the mine as possible. Few, if any, foresaw the time when taconite would be economic to mine. Therefore, it is not unusual to find valuable taconite resources located under towns and waste dumps on the Mesabi Iron Range.

Jan 1, 1980

By Jodi Banta

Thanks to strong industry support and longstanding partnerships, the University of Arizona has provided extensive pre-college mining education and outreach for more than a decade. These efforts to promote mining-related degree programs and the wide variety of indemand career opportunities reach thousands of middle and high school students and hundreds of teachers every year. The School of Mining Engineering & Mineral Resources is constantly looking at ways to help students overcome barriers into degree programs. But competition among degree programs for talent is fierce, and outreach has not made a big enough difference in the number of students pursuing mining engineering degrees. With workforce shortages threatening to undermine the industry, more is needed. The Bureau of Labor Statistics estimates 500 new mining engineering jobs each year, and according to a study by Deloitte (2023) nearly 50 percent of skilled engineers will reach retirement age in the next decade. At the same time, the 14 accredited mining or mineral engineering degree programs in the United States are producing fewer than 200 graduates annually (Society of Mining Professors and Society for Mining, Metallurgy & Exploration, 2021). To better understand mining’s competitive position, the School of Mining Engineering & Mineral Resources conducted a comprehensive study to determine (1) how prospective college students, parents and educators perceive the industry, related careers and the mining engineering degree, (2) factors affecting students’ choices of degrees and career plans and (3) the roles parents and educators play and how they influence students. This article is the first of two installments to discuss the results. This installment focuses on what students, parents and educators think about mining and where they get those impressions, as well as the role parents and educators play in influencing students’ choices of careers and degrees. The second installment, scheduled for publication in a later issue of Mining Engineering, looks at what students are seeking in their degrees and careers, and how mining compares with other degrees and industries.

Sep 1, 2025

By W. W. Dudley

The U.S. Geological Survey, in support of underground testing of nuclear explosives, has developed a technique (Dudley, 1910) to predict the inflow of ground water to large underground chambers that are cylindrical in shape. By treating the chamber as a large-diameter well pumped at constant drawdown, the nonsteady discharge can be computed by the method of Hantush (1961) for analyzing flowing wells under leaky artesian conditions. In mining applications, whether for mineral recovery or for nuclear testing, the most serious departure from the conditions of Hantush's model results from the gradual enlargement of the opening under drained conditions. Inherent in the analytical technique is that the "well" is fully completed at the time that dewatering begins. Because safety is the prime concern, however, initial pumping systems or personnel evacuation procedures must be designed to handle the greatest conceivable inflow. DEFINITIONS Because somewhat different meanings are attached to similar words in different technical fields, the U.S. Geological Survey definitions (Lohman, 1970) of several hydrologic terms used in this report are given below. An aquifer is a formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells, and springs. A confining bed is a body of material lying stratigraphically adjacent to one or more aquifers and having a hydraulic conductivity distinctly lower than that of the aquifer. The total head (dimensions L) of a liquid at a given point is the sum of three components: (1) elevation head, he, which is equal to the elevation of the point above a datum; (2) pressure head, hp, which is the height of a column of static water that can be supported by the static pressure at the point; and (3) velocity head, hv, which is the height the kinetic energy of the liquid is

Jan 1, 1971

By E. L. Piper

Natural graphite has been known for many centuries, having first been reported as a distinct mineral form by Gessner in 1565. At that time, graphite was used extensively as pencil "lead" because of the ease with which it marks paper. It is a black, unctuous material found as flakes, lumps, or needles in scattered locations throughout the world. The less crystalline, or "amorphous", natural graphites are thought to have been formed from coal under conditions of high temperature and pressure. The more crystalline varieties, such as those mined in Ceylon, probably were precipitated from molten solutions or were pyrolyzed from gaseous carbon compounds. Recognition of the good thermal and electrical conductivity of graphite, together with its highly refractory nature, led to an increasing number of appli¬cations for this material. Clay and pitch bonded natural graphite has been used in crucibles, refractories, foundry facings, and other high-temperature appli¬cations. These forms constitute the most important current uses for natural graphite in the United States. Other products containing natural graphite include batteries, lubricants, pencils, brake linings, etc.

Jan 1, 1973

By P. K. Sollars, M. A. Alspaugh

In May of 1996, Twentymile Coal Co. began Longwall mining in the Foidel Creek Mine's East Mine District. These Longwall panels are some of the longest in the world (5.48 km/18,000 ft) with very difficult and challenging geometry. The conveyance system is 1,800 mm (72 in) wide, has a 4,500 mtph (5,000 stph) capacity and employs multiple tripper drives. The trippers include traditional powering designs as well as unique regeneration and braking designs. Several components were developed specifically for this application including a mobile tail brake. Control algorithms were carefully developed and tested via computer modeling. A world production record was achieved in the third month of operation and over 1 million tons were mined in June 1997.

Jan 1, 1998

By S. Tuylu, D. Adiguzel, U. G. Akkaya, A. Bascetin

"One of the main problems for storing of the tailings is acidity occurrence due to several factors such as existence of sulfuric minerals and also the pollution in seepage waters by mobilization of metal ions, which holds great risks in terms of environmental regulations. Because of these specified reasons, tailing materials to be used in a SPD formula should have comply with some specifications. Among these properties; oxygen content, temperature, matrix suction and pH are the most important parameters. In the study, the relationships between the parameters mentioned are investigated to reveal optimum paste design layout. The lowest amount of seepage water obtained from the paste layers in the pilot cabinet was found as 2150 ml from 3rd layer. As for the maximum seepage water and the average of the all 11 layers were found as 4909 ml from 6th layer and 3273 ml respectively. The reactions occurring according to the oxidation, as seen at seepage water of second and third layers, decreased the pH of system to the under of 7 value. Additionally, when the seepage water of first layer’s EC value is 2.93 mS/cm, the EC value of second layer is increased at 3.54 mS/cm. The other parameters are evaluated with the obtained results of the tests to determine the optimum storing conditions for SPD.INTRODUCTION Conventional waste disposal methods, although widely used, pose great environmental risks. One of the most important issues is acid mine drainage (AMD). Tailings of metallic mines contain heavy metals, aggressive chemicals and hazardous materials. In the presence of oxygen and water, an oxidation reaction can occur, causing a decrease in pH of the environment, and heavy metals that are present in the environment can dissolve easily. Subsequently, heavy metals can pollute underground water basins, creating a great amount of danger for the ecology and potable water resources. Another important risk associated with conventional waste disposal methods is accidents related to the waste dam. Higher volumes of water and tailings (usually 15% solids and 85% water by weight) are sent to waste dams, making it very difficult to control the stability of the dam under conditions such as static and dynamic loads (seismic activities, vibrations caused by blasting, etc.), flooding, and seepage. In case of an accident or failure, the spread of great amounts of mud containing hazardous chemicals and heavy metals can harm the environment of the dam site significantly (Bascetin et al., 2014). In the paste technology, depending on the type of ore, tailings used in the paste mixture can contain sulphide minerals (such as pyrite and pyrrhotite). These minerals are known to be reactive with water and oxygen to produce acidity (sulphuric acid)."

Jan 1, 2015

By B. A. Wills

With the increasing need to mine lower grade ores, high energy-related costs in comminution are of major concern. Very fine grinding is needed to liberate the very fine mineral particles in these ores. Not only is this expensive but it leads to greater losses in 'slimes'. In the early 1970's, 50% of the tin mined in Bolivia, 30% of the phosphate mined in Florida and 20% of the world's tungsten were lost in this way (Somasundaran, 1979). Gravity concentration techniques become unacceptably inefficient for particle treatment below 25-50µm, and even flotation fails in the ultra-fine range. Two approaches can be adopted to try to overcome this problem. The first involves increasing the efficiency of existing equipment or developing new slimes treatment processes. Gravity devices such as the Bartles-Mozley concentrator have been developed for this purpose and good recovery has been reported from 100µm down to 5µm. Such machines, however, have relatively low throughputs, so that large areas of plant space are generally required. Flotation is rapidly growing in importance for the treatment of ultra-fine minerals traditionally treated by gravity concentration.

Jan 1, 1986

In 1992, United States mine production of barite decreased 8.5%. Barite consumption, sold or used by grinding plants, decreased by 36.9% and imports decreased by 61.6% vs. 1991. World mine production decreased 1.5%, according to the US Bureau of Mines. The value of domestically produced barite, f.o.b. mine, decreased 11.9% according to the Bureau. The declared value, c.i.f. United States port, of all imported crude barite during 1992 decreased from $42.35/t ($38.42/st) in 1991 to $40.09/t ($36.37/st). Nevada continued to be the leading producer of barite with 88% of the total, followed by Georgia and Missouri. It is estimated that 80% of the domestically mined barite was used as a weighting agent in drilling fluids. The remaining 20% was used in barium chemicals, glass or as a filler. Most of the production from Missouri, Georgia and Ten¬nessee was used in the non-oilfield sector. Of the total barite used by grinding plants and chemical manufacturers, it is estimated that 90% was used in drilling fluids and 10% in the non-oilfield sector. This included barium chemicals and fillers in paper, plastics and glass. The tonnage consumed in the drilling fluids market decreased due to the lower average rig count during 1992. The average number of rotary rigs operating (717) was 16.6% less than the 1991 average of 860 in the United States. Crude barite imports were 518 kt (571,000 st), 61.6% less than in 1991. Imports accounted for 44.7% of the barite consumed (apparent) in the United States. During the year, China continued to be the leading exporter of crude barite ore to the United States with 67.2% of total crude ore imports. India followed with 31 %, and others with 1.8%. About 90% of the imported barite ore was used in the oilfield sector. Ground barite imports decreased from 46.3 kt (51,000 st) to 30.9 kt (34,100

Jan 1, 1993

By C. B. Manula

A method for the feasibility assessment of open-pit operations using conventional shovel/ truck systems to mine steeply pitched coal seams has been applied at The Pennsylvania State University. Three computer models were developed for the analysis: a geology and reserves model (GEOL), an open-pit materials handling simulator (OPMHS), and a cash flow model (CASH) (Manula, Albert, and Burgos, 1976). GEOL provides the basic mining data; OPMHS simulates shovel/truck performance related to pit profiles and average mining locations to provide productivity rates needed to size the system; and CASH provides either a selling price or rate of return (ROR) for the product. The general flow of information generated by these models is shown in Fig. 1. Since the ratio of overburden-extracted to coal-produced places a definite economic limit upon a mining venture, geological data must be analyzed with the least possible manual effort to minimize computational errors. This is especially true if the property contains several seams that are steeply pitched. In this situation, a computerized analysis is by far the most efficient and effective method to determine coal reserves and waste tonnage. This chapter describes the reserve model developed at Penn State and provides an example to demonstrate its application.

Jan 1, 1979

By Michael S. Moats, John Bailey Fletcher

Wear rates of grinding media can be misrepresented by marked ball wear tests (MBWT). Galvanic interactions between dissimilar grinding media can be affected by the chromium content in the media and the presence of oxygen in the environment. Corrosion, one component of wear, can be affected by many variables. Corrosion rates and corrosion potentials for modern high chromium white iron (HCWI) and high carbon steel (HCS) grinding media samples were obtained through electrochemical testing. In this study, the impact of chromium content in the grinding media and the dissolved oxygen in a simulated mill water solution on corrosion rates and potentials was examined. Increasing chromium content in HCWI above 15 weight percent increases the corrosion potential and decreases corrosion rate. Removing most of the oxygen from the solution lowers both the corrosion potential and corrosion rate of the materials tested. The electrochemical results were examined to model possible galvanic coupling effects on corrosion rates. Galvanic coupling between HCS and HCWI could cause differences in corrosion rates for almost all scenarios modeled. Based on the galvanic coupling analysis, MBWT results could be impacted by mixing HCWI and HCS in a ball mill charge. This impact is predicted to be more significant when dissolved oxygen is present in the mill water and as the chromium content of HCWI is above 15 weight percent.

Dec 21, 2022

By Erik Westman, BEN WESTON, SETAREH GHAYCHI AFROUZ, KATHRYN DEHN

This study investigates the changes in seismic velocity of rockmass before and after three major seismic events to determine any potential identifiable precursory velocity changes associated with these events. Induced stress measurement is one of the challenging tasks in deep underground mining, with extreme impacts on the safety and stability of the mine. This study used p-wave passive seismic tomography to image the velocity redistribution within a rockmass, which can indicate induced stress level changes in the rockmass and detect the velocity changes that might precede a major seismic event or a rockburst. The ultimate goal of this research focus is to develop another tool for the deep-mining community that will help to increase safety and efficiency. For this purpose, the hypothesis of conventional mechanics, which implies induced stress at the hypocenter (as inferred by the p-wave velocity) increases until the seismic event occurs, is evaluated. It is found that the p-wave velocity did not increase at any of the three hypocenters prior to the seismic event occurring; however, the p-wave velocity did increase in the closest “zone center” for two of the three events. 

By H. K. Lin

The free-milling ore characteristics of the Fort Knox gold deposit are ideal for studying gold and silver behaviors in various processing circuits without serious interference of sulfide minerals and other refractory factors. A galvanic effect leads to faster silver dissolution than gold dissolution and, as a result, the Au/Ag solution concentration ratio increases through the leach circuit. In the CIP circuit, Au adsorption is more effective than Ag adsorption. The Au/Ag solution concentration ratio decreases from 10.0 to 1.0 as the slurry advances from CIP tank #1 to CIP tank #5, while Au/Ag ratio in the carbon increases from 3.2 to 15.3, as the carbon advances from CIP tank #5 to CIP tank #1. Silver is stripped more effectively than gold from the loaded carbon. The Au/Ag ratio in solution reaches 2.0 in the first 75,700 L of strip solution that pass through the loaded carbon; as the stripping process continues, the Au/Ag ratio in the strip solution increases. In the electrowinning circuit, the Au/Ag ratio in the spent electrowinning solution is significantly lower than that in the electrowinning feed, indicating that Au is more rapidly deposited onto the cathode than Ag.

Jan 1, 2010

By Tony Szwilski

A correlation between the rank, ash content and coal seam discontinuities and coal strength/stiffness is discussed. Rebound hammers were used to evaluate the strength properties of two coal seams. The coefficient of variability of the rebound tests are compared with those of laboratory compressive strength tests by other investigators.

Jan 1, 1985

By R. J. Nankee

Coal is our most abundant, low cost energy resource. Expansion of its use is being challenged due to "SO2 emission" regulation with even more restrictive legislation pending. High quality coal reserves are becoming more limited due to greater use in recent years. Aids to allow more use of coal in today's environment include beneficiation of coal before combustion and scrubbing the emissions from coal during combustion. Dow's efforts to help meet these challenges by beneficiating coal include true heavy media gravity separations with chlorinated solvents and liquid/liquid partitioning processes and "Dow Solvent Recovery Technology" to recover the solvent from product (or floats) and rejects (sinks), The objectives of the efforts to clean coal are to reduce sulfur and ash. In this paper, the solvents will be described; a general flow diagram presented; some of the results on upgrading various coals will be described, and projected costs of full-scale plants using chlorinated solvents will be compared to conventional cleaning plants.

Jan 1, 1985

By S. K. Mishra, S. B. Kanungo

Because conventional (physical) methods of ore dressing are not suitable for reducing the phosphorus contents of high-phosphorous manganese ores from Andhra Pradesh (AP) and the adjoining area in southern Orissa, India, the adoption of chemical methods becomes imperative. An attempt was therefore made to reduce the phosphorus content of partially beneficiated manganese ores from AP by roasting with sodium carbonate and then leaching with hot water. However, due to the higher phosphorus contents of the manganese ores from Nishikhal mines in southern Orissa, and because of their apparent resistance to dephosphorization by roasting with Na2CO3 alone, a mixture of Na2CO3 and NaCl was found to be necessary to reduce the phosphorus content to below 0.15%. Free-energy calculations at 700°C and above indicated that Na2CO3 (or Na2O as the active component) is a more active reagent than NaCl. Various process parameters, such as the temperature and time of roasting, the amount of sodium carbonate and the temperature and time of leaching, were studied to arrive at the optimum conditions for dephosphorization.

Jan 1, 2000