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By W. G. Stevenson

The centennial celebration of the AIME provides an opportunity to review some aspects of developments in mineral exploration since 1871 and to reflect on the changes that have occurred. During this period seven Factors have fundamentally altered the procedures, techniques and philosophy of mineral exploration. Although most of these developed gradually, and unheralded, they have drastically altered the art of exploration and discovery. 1. ADVANCES IN MINING AND MILLING The development of huge shovels, draglines, trucks and track-mounted drills, to replace the wheelbarrow and single Jack has drastically expanded the rate of production for both underground and surface mining. The development of selective flotation has had a far-reaching affect on mineral exploration and has made it possible to extract metals from the metallurgically complex deposits discovered years before. These developments have reduced the costs of mining and treatment, and have transformed material into ore that was considered waste one hundred years ago. These advances have permitted exploration for progressively lower grade and larger mineral deposits.

Jan 1, 1971

Mineral processing plant operators are faced with the necessity to choose between many different possibilities for plant improvement. Only a few such possibilities, however, can be tested on the industrial site. Steady-state simulators make it possible to assess the effects of several different flowsheet modifications in a few days, thus helping the process engineer to make his choice implement the solution that seems the most appropriate and check it. The example described here is the crushing and grinding circuit of the Shila Gold Mine, jointly owned by CEDIMIN SA and BUENAVENTURA SA, in Peru. Several possible modifications for the purpose of increasing capacity have been simulated and the results assessed in terms of technical quality, investment costs and energy consumption. The best solution indicated by the USIM PAC simulator was implemented and gave a 20% increase in capacity with a pay-back time of two months.

Jan 1, 1993

The Mine Safety and Health Administration (MSHA) has conducted studies to evaluate dust control technologies on deep cut continuous mining sections. These surveys have been conducted in different mines using various mining methods, face ventilation systems and dust control systems. The surveys typically consist of respirable dust sampling combined with a time study of mining activities. Measurements of dust control and operational parameters are also made. Critical elements identified for controlling respirable dust in deep cut mining systems include controlling intake dust, dust collector capacity, face ventilation quantities and velocities, positioning of workers, work practices and selection of equipment. This paper discusses how the dust surveys are conducted in deep cut mining sections and how these surveys are used to identify specific dust generating sources.

Jan 1, 1999

By David Hopkins, Steve Klein, Bradford Townsend, Ed Sum, Derek Penrice

INTRODUCTION The Transbay-Caltrain Downtown Extension (DTX) Project involves the construction of an approximately 1.5-mile rail line that will extend Caltrain commuter service and the future California High Speed Rail system into downtown San Francisco. The underground rail extension will be constructed by mined tunnel and cut-and-cover methods. Tunneling challenges include difficult ground conditions, low rock cover, the presence of historic buildings along the alignment, and the large tunnel span, ranging from approximately 50 to 65 feet. Three mined tunnel construction methods were evaluated: the Stacked Drift Method, the New Austrian Tunneling Method/Sequential Excavation Method (NATM/SEM), and Tunnel Boring Machines (TBM). This paper describes the challenges presented within the mined tunnel section, and summarizes the evaluation of tunneling methods that led to the selection of NATM/SEM. PROJECT OVERVIEW The existing Transbay Terminal opened in downtown San Francisco in 1939. This facility is antiquated, and does not meet current building seismic safety standards or the transportation needs of the Bay Area. For these reasons, San Francisco voters approved Proposition H in 1999, which proposed to construct a new or rebuilt regional transit center at the site of the existing terminal and extend Caltrain commuter rail ser-vice to the new transit center. The new transit center is the hub of the Transbay Transit Center (TTC) Program, which will greatly enhance regional transit service by providing connectivity for six Bay Area transit providers at one facility. The program will be the largest inter-modal centerwest of New York City. The TTC Program is comprised of two major projects, the Transit

Jan 1, 2007

By G. E. Maryniak

To date, human space exploration has been almost completely dependent on the use of resources carried with astronauts and cosmonauts from the surface of the Earth. The only exception to this has been the harvesting of solar energy to power space stations like Skylab, Salyut and Mir for long-duration missions. This dependence on materials which must be transported into orbit at costs in excess of $5000 per pound is the fundamental limiting factor in space exploration and operations. It is likely that launch costs can eventually be greatly reduced by means of such innovations as true single stage to orbit vehicles, aerospace planes, or serial electromagnetic or laser launch systems. However, the Earth will always remain an expensive source of materials for space construction and for basic commodities such as propellant and life support liquids and gasses. Fortunately, abundant sources of materials exist which are already in space, outside of the Earth's deep gravity well.

Jan 1, 1992

By J. A. Wallace

U. S. Steel's coal mining research activities are directed toward providing new or improved hardware and techniques to increase productivity or reduce cost. Because more than 80 percent of U. S. Steel's coal production is obtained from continuous miner sections, most of our research efforts are focused upon that mining system. Current and historical time study data show that our continuous miners only operate about 30 percent of the available face time. This limited equipment utilization is the result of the delays or interferences imposed by the non-coal-cutting phases of the continuous mining cycle. The most time consuming of these delays are: waiting-on-roof-support, tramming between alternate work locations, waiting-on-haulage-capacity, and in some mines waiting for excessive methane concentrations to clear. Because waiting on roof support is our most time consuming delay, several programs are underway simultaneously to address this problem. In one of these we are developing a patented microprocessor-based control method and apparatus to improve roof drilling performance. This increase is attained by using the microprocessor to adjust electrohydraulic valves which control drill thrust and rotation speed. The microprocessor is designed to continuously search for an optimum combination of thrust and drill rpm to maximize penetration rate at all times.

Jan 1, 1979

By J. Seifert, L. Hunter, P. W. Conrad, S. Rosenthal

"The goal of the protocol for reclaiming in-pit tailings ponds to exceed federal and state regulations was to develop a series of steps that can be followed to design, operate, and reclaim a tailings disposal pond that will develop into grazing land with a wetland for open pit sand mines in warm dry climates. By incorporating a wetland into the reclamation design, the post mining land use gives back to both the wildlife as a source of water as well as providing for a diverse range of post mining land use including but not limited to livestock grazing and ranch land use. An example design was completed using this protocol to demonstrate how the protocol can result in in a well-designed, reclaimed tailings disposal pond. BACKGROUND In an industry plagued with decaying historic mine sites, the public’s perception of mining appears to be poor. While modern mines are closely monitored and generally managed by ethical professionals, history still influences how the public perceives the mining industry. From collapsing abandoned underground workings to historic tailings dam failures, the failure to account for the environment in the past seems to affect public perspective on mining today. In a 2013 “Opinion Former Survey,” a survey conducted through interviews with a diverse range of stakeholders in various gold companies, it was noted that the most serious challenges facing the mining industry were environmental concerns and the permitting challenges associated with them (Council). In another article, this time focusing on Australian citizens and their perspectives of the mining industry, it was found that the majority of those surveyed had a big concern over the environmental impacts of mining especially when it comes to water quality and quantity (Scan). The statistics portrayed in these articles illustrate that today’s mining engineers needs to make more of an effort to change the public’s perspective of mining by being more environmentally aware. These engineers should be continuously asking themselves what they could be doing better from an environmental perspective to ensure that history is not repeated and that natural resources are used as efficiently as possible."

Jan 1, 2018

By S. Eugene Mills

Twenty-five years ago, when I began my sales life marketing minerals, there was little or no contact between sales people and production people. In those days, it was not uncommon for me, as a salesman, to learn of production problems existing in my company from my customers. Today, in my opinion, any successful mining company must keep production people fully aware of circumstances that effect service to the users of the product. Basically, feldspar is presently consumed by the glass and pottery industries the same as 100 years ago. The consuming public little realizes the origin of so many things they use daily and take for granted. Feldspar is utilized in the glass that contains our Coca-Cola, Pepsi, wines, liqueurs, beer and the assorted gob¬lets from which we drink these lovely brews, the industrial glass upon which all industry depends, the bathroom plumbing fixtures that make life so different from the days of the out-house, the beautiful and durable china we enjoy at mealtime. The electricity we use requires insulators that demand feldspar. In our home ap¬pliances, automobiles, toys and airplanes, we find feldspar. I could go on and on, hopefully soliciting your help in making our taxpaying and non-taxpaying fellow man aware of the burdens he may acquire when unthinking, over-enthusiastic environmentalists foist unnecessary hardships upon the mining industry. Feldspar is marketed primarily sized from 20 mesh to 325 mesh. The glass industry requires feldspar ground 20 mesh to 40 mesh size; the pottery industry requires material from 150 mesh to 325 mesh size. One large glass plant may require up to 100 tons per day and more, whereas a small plant may use less than 5 tons per year. A large pottery plant may require as much as 50 tons per day, a small potter only 500 lbs. per year. The feldspar

Jan 1, 1977

By F. W. Pereira

The Montana Talc ore body was discovered in the summer of 1983, in the Gravelly Range, approximately 25 miles south of Ennis, Montana. Initial drilling indicated a plus-million-ton ore body of high-purity talc. Preliminary analyses were performed on the ore cuttings, .including chemical analysis, brightness measurements, and microscopic evaluations of the structure of the talc. The results indicated the talc was similar to that currently being marketed from Montana and probably would have good commercial value.

Jan 1, 1989

By Cyril W. Draffin

Introduction Americans have long been proud of their ability to recognize a need, define it, and then develop workable solutions. The U.S. underground coal conversion (UCC) program is a good example. In 1974, the need to utilize coal resources that could not be mined was recognized, and Congress gave the Bureau of Mines $1.7 million to gain a better understanding of the UCC technology and its potential applications. Since 1977 when the U.S. Dept. of Energy (DOE) was formed, workable technologies have been tested, the market for underground coal conversion has been recognized, and extensive industrial interest has developed. Perspective The U.S. is blessed with extensive coal resources. Coal supplies about 19% of our national energy needs, yet recently promulgated environmental standards and increasing mining costs have limited direct coal use. UCC potentially can use coal that is economically or technically infeasible to mine because the coal is too thick, deep, dirty, high-ash, and wet; has an excessive angle of dip; or has unpredictable and poor overburden characteristics that make mining unsafe. Coal can be gasified underground or perhaps liquefied below the earth’s surface. Underground coal gasification (UCG) is the prime element of the underground coal conversion program. It enables coal to be converted to gas underground. UCC Coal Resource Recent data show a total U.S. coal resource base of about 6.4 trillion tons. Of this, 1.8 trillion tons might be accessed by UCC, including some minable coal. A commercial UCC process could quadruple roughly the 450 billion tons of U.S. coal reserves, which presently are recoverable by mining. The U.S. coal resources are divided into five sectors. The two most eastern sectors contain relatively thin, swelling bituminous coals that are difficult to gasify. Of the two, the bituminous coal in the Eastern Province is the most difficult because it is deeper than , in the Interior Province and the terrain is more rugged. The sector along the Rocky Mountains contains huge amounts of thick low-rank coals that are the most promising for early development by UCC. The coal has good continuity and the terrain is suitable. Low-rank coals such as subbituminous and lignite are highly reactive and tend to shrink and disaggregate when heated. Most of the coal in the Pacific

Jan 1, 1980

By Cyril W. Draffin

Introduction Americans have long been proud of their ability to recognize a need, define it, and then develop workable solutions. The U.S. underground coal conversion (UCC) program is a good example. In 1974, the need to utilize coal resources that could not be mined was recognized, and Congress gave the Bureau of Mines $1.7 million to gain a better understanding of the UCC technology and its potential applications. Since 1977 when the U.S. Dept. of Energy (DOE) was formed, workable technologies have been tested, the market for underground coal conversion has been recognized, and extensive industrial interest has developed. Perspective The U.S. is blessed with extensive coal resources. Coal supplies about 19% of our national energy needs, yet recently promulgated environmental standards and increasing mining costs have limited direct coal use. UCC potentially can use coal that is economically or technically infeasible to mine because the coal is too thick, deep, dirty, high-ash, and wet; has an excessive angle of dip; or has unpredictable and poor over-burden characteristics that make mining unsafe. Coal can be gasified underground or perhaps liquefied below the earth's surface. Underground coal gasification (UCG) is the prime element of the underground coal conversion program. It enables coal to be converted to gas underground. UCC Coal Resource Recent data show a total U.S. coal resource base of about 6.4 trillion tons. Of this, 1.8 trillion tons might be accessed by UCC, including some minable coal. A commercial UCC process could quadruple roughly the 450 billion tons of U.S. coal reserves, which presently are recoverable by mining. The U.S. coal resources are divided into five sectors. The two most eastern sectors contain relatively thin, swelling bituminous coals that are difficult to gasify. Of the two, the bituminous coal in the Eastern Province is the most difficult because it is deeper than in the Interior Province and the terrain is more rugged. The sector along the Rocky Mountains contains huge amounts of thick low-rank coals that are the most promising for early development by UCC. The coal has good continuity and the terrain is suitable. Low-rank coals such as subbituminous and lignite are highly reactive and tend to shrink and disaggregate when heated. Most of the coal in the Pacific

Jan 9, 1980

By Ehsan Alavi Gharahbagh

Tool and cutterhead wear is a crucial issue in soft ground tunneling, especially because tool inspection, maintenance, and replacement are done under difficult conditions, and often under pressurized faces or under ?hyperbaric interventions?. Overall, tool inspection and changing is a time consuming and costly step, which needs to be quantified and the related costs accounted for in any construction contract for scheduling and costing of the tunnels at design stage or bid preparation. However, lack of a universally accepted index or measure for soil abrasivity in the geotechnical reports has made it difficult, if not impossible, to define cutter wear for this purpose. Soil abrasion and its impact on cutting tools for tunneling machines under dry or wet conditions have recently been under spot light due to construction claims in several of the recent tunneling projects. The objective of this paper is to examine soil?s physical, mechanical and tribological properties related to the interface of the soil and excavation tools and discuss ways to measure soil abrasivity in a quantitative and repeatable manner. The paper will discuss the efforts that are underway to develop a new soil abrasivity index and the fabrication of a new testing device for this purpose.

Jan 1, 2010

By David Atkin

This paper presents methods and results of environmental planning conducted for a proposed coal and iron ore transshipment terminal which would be located on reclaimed land west of Lisbon, Portugal. Oceanographic, navigational, marine, structural, material handling, and financial studies of the terminal were conducted along with the environmental analyses. However, because of the proximity of the terminal to heavily used recreational resources, residential areas, and biologically valuable habitat, anticipating and reducing the environmental effects of the terminal to minimum levels was a very important part of the overall project. The results of the study indicate that even the impacts associated with worst-case conditions would be acceptable because of appropriate pollution control measures and planning.

Jan 1, 1983

By J. G. Groppo, J. G. Justice, B. K. Parekh

Removal of particulates and/or metal ions from mineral/coal processing waste water is a necessity from the environmental point of view. This paper describes application of a novel AC- electrocoagulation technique to remove the particulates as well as metal ions using AC power. A series of laboratory tests conducted on a stable black water sample obtained from a sub-bitminous coal operation provided a clear supernatant (-10 NTU) from the suspension. The process also shows promise in removal of up to 90 percent of phosphate ions and other metal ions (copper and nickel) from solution. A preliminary economic evaluation of the process will also be included.

Jan 1, 1992

By G. J. Joy, J. P. Rider

"Technical advances in longwall mining over the last several years have resulted in much larger and faster shearers that have the capability of mining at speeds over 100 ft./min. This has resulted in a substantial increase in the amount of dust that is generated at the shearer and during shield advances. Meanwhile, increased underground coal production has put a greater demand on longwall dust control systems as some operators have had difficulty maintaining consistent compliance with federal dust standards. To address this need, the National Institute for Occupational Safety and Health [NIOSH] is investigating the effectiveness of a water spray manifold mounted on the tailgate end of the shearer body. The sprays are oriented parallel to the tailgate ranging arm, and these sprays create a water curtain confining the dust plume near the face, preventing the dust from drifting into the walkway. This redirection of dust provides a clean air envelope for the tailgate shearer operator and jacksetters working near the tailgate drum. Three different tailgate spray manifold designs were tested and evaluated at the Office of Mine Safety and Health Research [OMSHR] Pittsburgh Longwall Test Facility. Manifolds were equipped with hollow cone or flat fan water spray nozzles and evaluated at three face air velocities (500, 700, and 900 fpm) and at water pressures of 100, 150, and 200 psi. Reductions in dust concentrations were observed at six face sampling locations for all the tailgate manifold systems at each of the tested spray pressures and face velocities. Based on results from the laboratory tests showing reductions in dust concentrations at sampling locations downwind of the shearer a spray manifold was fabricated and evaluated at an underground operation. INTRODUCTION In 2012, underground coal mining in the United States produced a total of 342 million short tons, with longwall mining accounting for over 53% of this production [EIA 2013]. The longwall mining industry continues to see remarkable and significant improvements in longwall mining equipment and mining practices. Average shift production during compliance dust sampling has increased from 3,500 tons per shift in 1994 to approximately 6,000 tons per shift in 2012. A dramatic decrease in working longwall faces from 80 to 49 has occurred over the same period [Fiscor 2013]. Factors specific to longwall mines that supported productivity improvement include: higher capacity shearers, improved shield hydraulics and control, higher horsepower for equipment, wider face conveyors, and larger faces. Today, the average face width has increased to 1,188 ft., with one longwall operation reporting a face width of 1,650 ft. compared to an average of 750 ft. in 1994 [Fiscor 2009, 2014]. Panel lengths in 2013 averaged 11,307 ft. compared to 7,000 ft. in 1994. Overall production from U.S. longwalls has increased by nearly four percent from 2007 to 2012 with over 182 million tons mined annually [EIA 2013]. Given the volume and rate of coal produced on longwall faces, the potential to generate large quantities of respirable coal mine dust also exists."

Jan 1, 2015

By M. Moats

Copper electrowinning operations have dramatically improved their ability to produce high quality copper at low costs over the past several decades. Even so, some fundamental knowledge is still lacking that could allow operations to run even more efficiently. For example, a rule of thumb exists that estimates a current efficiency loss of 2-3% per gram per liter of iron in the electrolyte. While several laboratory studies have been performed that demonstrate this rule of thumb is likely true, no definitive relationship exists. In this paper, the first steps in developing a definitive relationship are presented. The effective diffusivity of ferric ions in synthetic copper electrowinning solutions was measured using chronoamperometry and the Cottrell equation. The effective diffusivity of ferric ion was determined as a function of electrolyte concentration and temperature. Synthetic electrolytes were then used in laboratory-scaled copper electrowinning experiments, where relationships between current efficiency and solution composition were found to exist under stagnant conditions. Key words: Copper electrowinning, Current efficiency, Chronoamperometry, Ferric ions

Jan 1, 2009

By Amy McBrayer, Andrea Brickey

The paper discusses the mine planning methods used in the Powder River Basin (PRB), highlighting the differences from open-pit metal mines. It emphasizes the need for agile mine operations due to changing commodity markets and the challenges faced by the coal industry, such as volatile prices and reduced engineering manpower. The study includes a survey of mine engineers to document current practices and identify potential improvements.

Sep 1, 2023

By Bill A. Hancock

In Situ leaching for the recovery of uranium from low grade sandstone deposits is one of the newest technological advances in the mineral industry. It is rapidly developing into a commercially feasible mining system which has economic, environmental, and social advantages over conventional mining systems. Because of the current uranium shortage, development of In Situ leaching into a sophisticated system has gained new impetus. In Situ leaching will become an important mining technique in the future, which will greatly help to supply uranium for our nation's energy heeds. In this paper, I will be giving an overview of the merits of the system, as well as the technology, problems, and research in solution mining of uranium.

Jan 1, 1977

By George McArthur

GEOLOGY One of the largest copper resources in North America occurs in the Bingham mining district, located 40 km (25 miles) southwest of Salt Lake City, UT. Anaconda's present contribution to the development of this resource is the Carr Fork mine. (Fig. 1, Bingham district plan map.) The Carr Fork story began about 300 million years ago when a thick sequence of sedimentary quartzite and limestone was deposited in the Oquirrh Basin. Subsequent earth stresses formed a series of west-northwest-trending overturned anticlines and synclines that were later offset by northwest-striking thrust faults and northeast-trending normal faults. (Fig. 2, Bingham district cross section.) About 38 million years ago the Bingham stock was intruded into some of the folds, resulting in the formation of porphyry ore in the intrusive, and fissure, replacement, and skarn ore deposits in the sediments. The Carr Fork skarns were formed preferentially in two limestone units, called the Yampa and Highland Boy, which average about 46 m (150 ft) in thickness, separated by about 76 m (250 ft) of quartzite. Copper mineralization consists almost entirely of chalcopyrite associated with pyrite and molybdenite in a gangue of garnet, diopside, magnetite, quartz, and carbonate. Molybdenum, gold, and silver are economic byproducts. (Figs. 3 and 4, indicated ore in plan and section.) EXPLORATION HISTORY The West Mountain mining district, of which Carr Fork is a part, was organized in 1863, after leaf-silver ore was discovered in the Carr Fork of Bingham Canyon. However, it was not until 1873, when the Bingham and Camp Floyd railroad to the town of Bingham was completed, that the mining camp flourished. Many small mining companies in the district were reduced, often through consolidation. By 1937 only the National Tunnel and Mines Co. was active in the Carr Fork area. In 1948 it declared bankruptcy, and was later purchased by The Anaconda Co. Anaconda conducted geologic investigations in the Bingham district until 1968, when a concerted diamond drilling program was initiated to fully evaluate the geologic potential of the Carr Fork area. The exploration program commenced with one diamond drill, but was enlarged to three drills following discovery of the first major ore intercept. Near completion of the exploration effort, large oil well rotary drills were used to drill to depths of 762 to 914 m (2500 to 3000 ft), after which the holes were completed by standard diamond drilling techniques. All holes were collared vertically, but considerable deviation occurred because of structure and rock conditions. Wedging and directional drilling were used to keep the holes on target and to provide multiple ore intercepts in the deeper holes. Geophysical surveys, in-

Jan 1, 1982

By George Hufford

An investigation is made into the applicability of queueing theory to simulating the operation of a large open pit copper mine in the southwestern United States. Actual data from a working mine was used to construct curves for truck loading time, haulage and return time, and dumping times. Known results of investigations of queueing models (Koenigsberg - 1958, Gordon and Newell - 1967, Cabera and Maher - 1973) were used to simulate the actual operation. These did not give acceptable results so commonly used probability distributions were fitted to the actual data. A large computer program known as Q-GERT was used with the various parameters obtained from fitting the curves. Kolmogorov- Smirnov tests were run that showed that this was not satisfactory either. Finally, Q-GERT was used with the actual data from the mine. An appropriate correction factor is then found to apply to the exponential probability distributions tested previously and satisfactory results are obtained.

Jan 1, 1981