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By K. Nielsen

The paper presents a brief overview of the mineral industry in Norway, followed by a description of the mineral policy and relevant legislation including the roles of the Norwegian Directorate of Mining and Geological Survey of Norway in this context. The discussion then proceeds to describe the land use planning framework on a national, regional and local level, the interaction between land use planning and the Directorate of Mining and the Geological Survey respectively, and how this impacts on the mineral industry and the exploitation of mineral resources. Some recent Norwegian examples of land use planning conflicts are also presented.

Jan 1, 2005

By T. A. Oberhellmann

The Wobbler Feeder is a comparatively new materials handling and separating device. It is essentially a materials separating or scalping machine, particularly adaptable to separation of oversize particles from mine-run ore and to the separation of oversize materials from overburden, where the removal of oversize materials is necessary, as is the case in conveyor stripping. In construction, the Wobbler Feeder is simply a set of transverse bars of manganese steel, or other wear-resisting alloy steel, each having an elliptical cross-section with the major axes of adjacent bars displaced by ninety degrees so when rotating in unison, the pre-determined space between the bars remains constant.

Jan 1, 1959

By J. Platt

Recent EPRI research on utilities? likely strategies to reduce sulfur emissions differs sharply from policy analyses showing all- switching or all-scrubbing choices. Energy Ventures Analysis, with Stearns-Catalytic and A. T. Kearney, estimated sulfur-removal costs for scrubbing or switching at virtually all affected plants in the 31 Eastern States. Cost tradeoffs occur between $30 and $40-plus per ton FOB mine in Central Appalachia ($33-44-plus per tonne). 1/2 to 3/4 of total sulfur reductions comes from scrubbing, whose costs act as a cap on low-sulfur coal prices. In a severe environmental scenario, low- sulfur coal demand evaporates, replaced by very low-sulfur (0.7%) coal demand. Additional findings and implications of EPRI coal supply and market studies will be reviewed.

Jan 1, 1987

By John Dasher

In 1980, some US cars were designed and built to metric dimensions; wine and gas were sold by the liter; and the March of Dimes Walkathon was measured in kilometers. Although the US Congress has taken a ''soft" approach to metrication, and public resistance to the idea remains strong, the use of metric units is becoming more and more widespread. As the minerals industry becomes more international in scope, US mining companies are converting to the metric system-particularly those companies with business interests overseas.

Jan 2, 1981

By N. R. Allen, J. D. Steenkamp

Oxidative roasting is applied on an industrial scale to beneficiate ilmenite concentrates from South African East Coast heavy minerals deposits - the aim is to increase the magnetic susceptibility of ilmenite to allow magnetic separation from chromite. The intention of this paper is to give researchers new to the field an overview of the beneficiation of ilmenite through roasting and magnetic separation, touching on the relevant fundamental aspects of magnetism.

Jan 1, 2005

By Z. T. Bieniawski

The efficient and safe design of room-and-pillar coal mines still remains as one of the pressing problems facing the mining industry in the United States. Although much research has been directed to stability of mine roofs and coal pillars, no generally-accepted design method has been formulated. This paper presents a concise procedure for an improved design of room-and-pillar coal mines. Developed as a result of a three-year research effort, the methodology includes essentially three aspects: (i) determination of stable roof spans; (ii) determination of the strength of coal pillars; and (iii) determination of safety factors for room-and pillar coal mining in the United States. It is shown that the presented approach will lead to a greater recovery of coal by a more economical, yet safe, mining operation. Design charts and tables are presented and a step-by-step design procedure for practical mining engineers is explained. Several examples are included demonstrating the use of the proposed design procedure for room-and-pillar coal mines.

Jan 1, 1983

In its April 1991 issue, MINING ENGINEERING published a salary survey form asking for information relating to engineering and management jobs in the minerals industry. 1038 of these forms were filled out and returned, most of them being received in the magazine's offices at SME headquarters before the end of June 1991. An SME volunteer took on the task of tabulating and analyzing data from the forms, but the press of other business interfered with this work, and publication has been delayed until this issue of MINING ENGINEERING. Appreciation is extended to SME members who took the time to fill out and return the salary survey forms, and our apologies go to MINING ENGINEERING'S readers for the delay in publication. Of the total number of forms received, more than 97% were from SME members. The geographic distribution of the respondents closely mirrored that of SME membership as a whole, about 50% being from the Society's Western Region, 19% from the Central Region, and 23% from the Eastern Region. About 8% were from outside the US. Average salaries for each of the four geographic areas ranged between $55,000 and $60,000, with the highest average in Eastern Region (Fig. 1). Respondents were asked to answer a number of questions formulated to determine if there are significant differences in salaries based on the type of organization for which they work. As indicated by Table 1, salary averages at mining companies do not vary markedly with the size of the company: • Large companies, defined as those having more than $1 billion in annual sales, accounted for just over 16% of the returns. Their average salary was $61,840 per year.

Jan 1, 1992

By M. A. Trevits, A. Ozment

"According to the Office of Surface Mining Reclamation and Enforcement Abandoned Mine Land Inventory System, in 2013 there were 98 underground mine fires burning in 9 states. This is considered by experts to be an underestimate for the actual number of fires nationwide. Abandoned mine fires, if left uncontrolled can burn for years and in fact, one of the most well-known mine fires in the US, the mine fire in Centralia, PA, which began in 1962 has been burning for over 55 years. In Centralia, the mine fire won the battle, despite suppression and control efforts, as most of the residents were bought out by the State of Pennsylvania and moved away. However, the world record for the longest-burning coal fire, which may have been started around 6,000 years ago in New South Wales, Australia is still smoldering. Suppressing a coal mine fire requires cooling the hot zones and removing any source of oxygen. If the workings are shallow, the fire zones can be unearthed and the burning rock mass can be quenched on the surface. If the workings are too deep to excavate, then the fire must be fought remotely through boreholes using a variety of agents including water, gas-enhanced foam and grout. Access to surface areas for drilling can be problematic due to topographic and property constraints. When this occurs, large areas of burning may go unaddressed or simply left to burn. Fire Solutions, Inc. has been investigating the use of gas-enhanced foam in concert with directional drilling technology. Gas-enhanced foam has the advantage of using less water and adds inert nitrogen gas to displace oxygen to infiltrate and suppress a fire. Directional drilling has the capability to steer a borehole to a specific place underground. Directional drilling has many advantages over conventional drilling technology as it can provide the least disruption to the ground surface, minimize surface preparation and reclamation costs, multiple sites can be accessed underground from a single site and thus treated simultaneously and it offers increased efficiency because it is not constrained by difficult terrain. This paper discusses the combined use of these two technologies and it is hoped that with the use of these two technologies the efficiency and capability to address mine fires will be significantly improved. INTRODUCTION According to the Office of Surface Mining Reclamation and Enforcement, Abandoned Mine Land Inventory System, in 2013 there were 98 underground mine fires in 9 states. This is considered to be an underestimate for the actual number of fires nationwide. Many mine fires are started by people burning trash where the coal seam or an abandoned coal mine is close to the surface. Other fire ignition sources include lightning and forest fires. Once ignited, a coal mine fire can easily spread into the remaining coal pillars and mine entries. Once established, the fire creates its own ventilation system supporting further combustion by drawing air down into the workings through unsealed mine shafts, fractures and surface subsidence depressions. As the coal left in the workings from the past mining operations burns, the mine void can collapse, causing subsidence and creating dangerous voids, damaging damage overlying surface structures and roadways. The products of combustion include smoke and noxious fumes such as carbon monoxide gas. These products are released to the atmosphere through fractures that develop within the ground surface, killing vegetation and creating serious health hazards [1]."

Jan 1, 2018

By Ruben Piqueras, Juan Luis Magro, Jorge Vázquez, Santiago Martínez, Xavier Manjarín

The Parallel Thimble Shoal Tunnel project involves the construction of a bored tunnel under Thimble Shoal Channel in Chesapeake Bay (VA), between two artificial islands and parallel to the existing tube tunnel, built in the sixties. It will be the first transportation tunnel constructed in the Mid-Atlantic region using a Tunnel Boring Machine (TBM), a 44-foot-diameter Earth Pressure Balance (EPB) named "Chessie," manufactured by Herrenknecht, and which was assembled at the CBBT's southernmost island, with extremely limited room, live adjacent traffic, and difficult access. "Chessie" was successfully launched in February 2023 and this paper describes this complex and challenging process.

Jun 23, 2024

By C. Gherghel

The planning and operation of ventilation network systems for uranium mines require special considerations since ventilation is the primary technique of controlling ambient concentrations of radon progeny. The major environmental challenge facing the ventilation engineer is the requirement to dilute radon progeny to below the Working Level Month per year of worker exposure required by law. The application of large airflow volumes and the utilization of low residence times constitute some of the factors considered by the design engineer. Good mine planning and sequencing are also critical for protecting the health of miners. The mine ventilation must have such characteristics as flexibility, high air distribution efficiency, rapid air transit times, zero recirculation and no short-circuiting. A well established maintenance program for all ventilation appliances must be in place to guarantee control of the distribution system. Real-time monitoring systems permit assurance the adequate quality of air is delivered to working places. A case study for an operating mine is used to demonstrate how the ventilation system is successfully managed and operated using the above concepts.

Jan 1, 2009

By M. T. Smith

In a 2,000 square mile area of Polk, Hillsborough, Hardee and Manatee Counties in Central Florida is located one of the richest known deposits of the life-giving mineral, phosphorus. Under layers of sand and clay are found millions of tons of phosphate rock, best source of this element which is necessary to all forms of life - plant, animal and human. Phosphorus is an irreplaceable ingredient in all complete plant foods, and more than 90% of Florida's vast production goes to enrich the croplands of the United States and many other areas of a hungry world. In addition to this, it has wide industrial use in the manufacture of many products - detergents, baking powder, carbonated beverages, steel, matches, munitions, glass, insecticides, dyes, water softeners and innumerable others. Not only does phosphorus make life possible for us - it also helps us to live longer and better.

Jan 1, 1962

By Gary E. Slagel

The year was 1974. The event - the United States Congress was embroiled over what issues should be included in the proposed national surface mining law. The question - what should be done with underground mines? The leading bills ultimately addressed the environmental impacts associated with underground mines including provisions to protect the surface from subsidence impacts. Amid the fears that this subsidence language might discourage underground mining, sponsors of the bill were asked to explain the meaning of the provision that read "to prevent subsidence to the extent technologically and economically feasible." Was this an attempt to limit mining that caused planned and controlled subsidence? Former Deputy Director of the Office of Surface Mining, Dean Hunt, reviewed some of these historical events in a 1985 presentation before the Eastern Mineral Law Foundation. He reported that in 1974 Congressman Morris Udall took the floor to respond to these concerns expressed by other members of Congress and the industry. Mr. Hunt cited Congressman Udall's July 10, 1974 Congressional Record statement: "The House bill contemplates rules 'to prevent subsidence to the extent technologically and economically feasible.' The word prevent led to fears expressed by the Secretary of the Interior Morton, that the effect would be to outlaw longwall mining, with its obvious subsidence ... in fact the bill's sponsors consider longwall mining ecologically preferable and it and other methods of controlled subsidence are explicitly endorsed." Further, the report that accompanied the front-running bill, HR11500, provided the following clarification on the issue of subsidence prevention: "It is the intent of this section to provide the Secretary with the authority to require the design and conduct of underground mining methods to control subsidence to the extent technologically and economically feasible in order to protect the value and use of surface lands. Some of the measures available for subsidence control include: (1) leaving sufficient original mineral for support; (2) refraining from mining under certain areas---or (3) causing subsidence to occur at a predictable time and in a relatively uniform and predictable manner. This specifically allows for the uses of longwall and other mining techniques which completely remove the coal." It is clear from the preceding statements that Congress considered the removal of all the coal and causing subsidence in a predictable and uniform manner to be equal to or better than leaving support coal and causing no subsidence. While the actual provision in the bills talked of preventing subsidence, a subsequent exception made it clear that the real intent was to control it. This is evidenced in the specific planned subsidence language that appeared in the bills and ultimately in Section 516 (b) (1) of PL95-87, the Surface Mining Control and Reclamation Act. It reads: "...adopt measures...to prevent subsidence ... except in those instances where the mining technology used requires planned subsidence in a predictable and controlled manner..." In spite of this historic record that supports controlled subsidence, something has been lost in the implementation. The primary focus by many regulators over the past few years has been on the "prevent" aspect irrespective of mining method being used. This has appeared to change the original intent of Congress from one of controlling subsidence to one of minimizing damage. The objective of this report is to review some of the current regulatory issues that impede full extraction mining and offer some suggestions on possible ways to deal with these issues.

Jan 1, 1986

By Allan G. Provost

Shaft construction is assuming ever increasing importance when new mining enterprises are considered. The reasons for this increased emphasis is the much greater depths at which many new ore-bodies are being developed and the rapid depletion of near surface reserves requiring mines to go to greater depths on existing deposits. These greater depths increase the probability of exposure to unfavorable geologic conditions and it is more likely that high ground and/or water pressures will be experienced at these depths. The large capital costs involved and the critical position of a shaft in the overall mining program necessitate that this element of project development be given careful and critical consideration. The Henderson No. 2 Shaft is located in the Rocky Mountains of north central Colorado (See Figure I), about 55 miles west of Denver, near the community of Empire in Clear Creek County. At the 10, 442 foot collar elevation, winter arrives in late September and brings snow to contend with until May. The labor force for Shaft No. 2 is approximately 90 men. They are provided access to the project via all-weather U. S. Highway 40. SHAFT DESIGN The Henderson No. 2 Shaft is a 28-foot I. D. circular, concrete lined (1 foot thick) vertical shaft. The final depth will be approximately 3100 feet

Jan 1, 1972

By Jr. Pitts

Elevation of surface charge density on colloidal particles in the presence of a high potential electrostatic field is demonstrated as a viable technique for preventing the accumulation of solids in solvent extraction circuits. The effect of the technique is manifest by relative turbidity measurements between pregnant leach solution and raffinate, by changes in the character of the sludge accumulations, by alteration of the zeta potential of particulates, and by a general reduction in the mass of solids.

Jan 1, 1992

By Stanley N. Watowich

Recently the petroleum market has made us aware that we are indeed global natural resource consumers, and as such, we have become captive to fundamental global resource economics and their attendant vagaries. Global resource supply problems are as old as civilization and mineral exploration one of its important catalysts. On the basis of natural resources empires have been expanded and new frontiers have been developed. Global consumption and production might even be viewed idealistically as a system dedicated to optimizing distribution to the consumer. However, this is not the case. Political instability and increased government polarization make dependency on a global market somewhat insecure. The U.S. must evaluate its domestic mineral re- sources on the basis that all metals are critical and that dependency on even the common and base metals may ultimately weaken our domestic economy and our potential international relationships and could cause critical weaknesses as demonstrated by the petroleum problem. This paper evaluates specifically the Duluth Gabbro Complex, of Northeastern Minnesota, (figure l), as a potential resource of critical and strategic metals. First, a chronology of some of the early exploration, will be followed by more recent intensive company studies and preliminary evaluations of economic feasibility. Lastly, metallurgical data, on some optimum conceptual mining plans will allow metal production data to be compared with an estimate of U.S. domestic needs in 1990. The purpose of this paper is to put into focus the difficulty of converting resources into vitally needed reserves.

Jan 1, 1981

By William Gleason

There was a time, not too long ago, when the most daunting challenges facing those in the mining and mineral processing industries could be solved through better technologies and better practices. But now the challenges that come from the actual acts of mining and processing are just part of the bigger picture. SME?s Colorado Section of the Mineral Processing Division (MPD) hosted its 63rd annual meeting at the Broadmoor Hotel in Colorado Springs, April 25-27 and, while the conference had its fair share or mineralolgy and processing presentations that were heavy on the technical side of things, this year?s conference was also focused on the issues of permitting, regulation compliance and legislative issues. The so-called ?softer? issues, that, if not addressed, can lead to very real and very hard challenges. Under the theme ?Mine your own business - permits, startups, expansions and resources,? even the most dedicated metallurgists were drawn into the discussions of politics and legislation, and how those issues affect their business. Fittingly, Colorado Mining Association (CMA) president Stuart Sanderson was honored with the Arthur C. Daman Lifetime Achievement Award. Sanderson, an outspoken proponent for the mining industry in Colorado and beyond, also presented the keynote address to the lunch crowd where he spoke about framing public opinion toward mining and the efforts of the CMA to move the public opinion dial in a direction more favorable to mining. Sanderson explained that Colorado, once a Republican stronghold, turned after 2002 and now is controlled by Democrats who are traditionally less supportive of the mining industry. Sanderson said the deciding factor in the power shift was money, as supporters of Democrats outspent Republicans in the most recent election cycles. CMA has done its part to keep mining going in the state with a broad marketing campaign that was outlined by Sanderson.

Aug 1, 2013

By C. Bise, A. Seal

Excessive noise has long been a hazard in the coal-mining industry. Studies conducted during both the mid-1970s and the mid-1990s consistently show that hearing hearing loss within the mining industry persists, in spite of regulatory requirements and sampling technology advances. When MSHA’s new health standards to protect miners from hearing loss took effect in September 2000, the potential developed to re-evaluate sampling approaches with regard to noise-source hazards, such as task-based methods. This paper describes results from a Penn State research project currently being conducted at an underground coal mine. Each occupation was reviewed, and a list of tasks or processes performed by each was generated. Traditional personal noise dosimetry, static sound pressure levels, and equipment sound mappings have been performed. Job tasks indicating the greatest levels of daily noise exposure and contributions to noise dose have been identified and will be discussed.

Jan 1, 2001

By Akira Tsune, Shingo Sugimoto, Tadayuki Ishiyama, Nadao Saito, Masatsugu Okazaki

"The Deep Ocean Resources Development Co. Ltd. (DORD) of Japan signed a 15-years contract with the International Seabed Authority for exploration of polymetallic nodule in a 75,000 km2 area, consisting of West and East Areas in the Clarion and Clipperton Fracture Zone in 2001. The exploration work is now concentrated in resource estimation of the first generation of mining area, the High Abundance Area.A detail survey of the Model Area, set in the High Abundance Area, was conducted using AUV (Autonomous Underwater Vehicle) equipped with MBES (Multi-Beam Echo Sounder), SSS (Side Scan Sonar), Sub-Bottom Profiler (SBP) and still camera. The seafloor topographic map based on 1 m grid data was produced in an area of approximately 80 km2 (Figure 1). Photographs, continuously covering the seafloor taken by AUV along two west-east trending traverse lines, together with detail seafloor topographic map produced from MBES give an excellent opportunity to observe distribution manner of pollymetalic nodule related to topographic features. This helps to understand more accurate resources estimation of a whole area of the High abundance Area. Furthermore, information of micro-topography gives ideas for conducting ore collecting operation and designing ore collector."

Sep 1, 2014

By R. Brändle, R. Luis-Fonseca, R. Cornejo, G. Fischer, G. Von Rickenbach, J. Jarufe

Rock damage around underground excavations has been an important hazard in mines and tunnels. Rock dilation generates buckling that needs to be contained before it causes damage to equipment or safety concerns to mine workers. In seismically active mines, rockburst occurrence has been widely recognized as one of the most important hazards in deep mines and tunnels. While there is a wide range of cases where rockburst hazard can be mitigated through dedicated excavation sequences, reentry procedures or exclusion zones, there are still many situations where large unexpected rockbursting may occur, relying only on rock support as the last mitigation measure to prevent production and safety losses. Considering the previous situations, surface support as mesh, plays a major role containing the failed/ejected rock and providing a safe working environment to the underground operations. While there have been considerable achievements in improving mesh resistance, with more than 26Kj/m2 of energy dissipation capacity, there is still a lack of research in the overlapping mechanism and load transfer between contiguous mesh elements. This paper presents the state of the art in static and dynamic analysis of welded and rolled mesh overlaps, based on experimentation carried on by Geobrugg in their Research Center, leaving clearly established that the difference in meshes is not only in levels of energy absorption, but also concluding that in the case of high resistance rolled meshes overlapping is not necessary and the transmission of stresses can be fully guaranteed by using suitable connecting elements. All these characteristics, supported by operational advantages as light weight and mechanized mesh installation, provides a considerable improvement in safety and productivity, improving the economic value of the project

Apr 26, 2022

By Thomas L. Hurst, Joseph M. Hans

INTRODUCTION The former Shiprock uranium mill site is located in the community of Shiprock, New Mexico on a bench overlooking the San Juan River (Figure 1). Both Shiprock and the mill site are located on the Navajo Indian Reservation. The millsite was built on a 230 acre tract leased by Kerr-McGee Oil Industries Inc., and was operated from 1954 to 1963. The Vanadium Corporation of America and its successor, the Foote Mineral Company, operated the mill from 1963 to 1968. During its entire operation, 1.5 million tons of uranium ore was milled producing 3711 tons of U308 concentrate. The concentrate was sold to the former U.S. Atomic Energy Commission. During milling, the ore was crushed to less than 35 mesh and acid leached to remove the uranium. The [ ] uranium was removed from the leach solution by solvent extraction and the uranium-barren solution discharged into raffinate ponds for disposal by evaporation and seepage. The spent solids (tailings) were pulped with waste process fluids and water and discharged to form tailings piles. The piles (ponds or dams) were formed with earth starter dikes. The dike walls were then raised using the separated sand fraction of the tailings. The slime fraction of the tailings were discharged into the diked impoundment. Since only a small fraction (0.25 percent) of the ore was U308 by weight, most of the ore bulk ended up as wastes. The wastes contain nearly all of the uranium decay chain radionuclides present in the ore except uranium. The mill was shut down and partially dismantled before the lease expired in 1973, and the remainder of the mill and wastes reverted back to the Navajo Tribe which was the lessor. Portions of the millsite were then occupied by the Navajo Engineering and Construction Authority (NECA), a Tribal enterprise. In order to provide skilled personnel to operate earth moving equipment, a heavy equipment operator's training school was also established on the mill site and was administered and operated by NECA. The U.S. Public Health Service (PHS) and the Environmental Protection Agency (EPA) staff conducted radiation surveys at four inactive uranium millsites on the Navajo Reservation in April 1974. During the survey of the Shiprock millsite, it was noted that the training activities were degrading its radiological condition. Both the PHS and EPA staff recommended that the training activities be directed towards the decontamination of the millsite area and interim stabilization of the tailings piles. Preparation for the decontami-nation work commenced in April 1974. In order to facilitate the decontamination activities, the mill site and its contaminated environs were divided into major areas labeled A through F (Figure 2). Areas A, B, and C are defined as "perimeter" areas and contained surface contamination ranging from 5 to 30 cm deep. Area D defined the mill yard and contained contamination ranging from 0.6 to 5.5 m deep. Area E contained several raffinate ponds which were removed to line up the northwest boundary of the tailings pile and to move the contaminants away from the vicinity of the occupied on-site buildings. The contaminants in Area E ranged from 0.05 to 5.5 m in depth. Area F encompassed the ore storage yard. Contaminants in this area ranged from 0.18 to 1.2 m deep. Washes, however, had contamination exceeding 7.6 m deep.

Jan 1, 1981