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"What is your assessment of the minerals business?My experience with mining has been primarily in the coal sector until about 10 years ago, when I also became heavily involved in the aggregates and industrial minerals sectors. I have also had peripheral involvement through family and partners in the gold sector, with just enough exposure to gold to become fascinated. In 1994, I visited Ghana and considered the possibility of taking an expat assignment at a surface gold mine that had just been started.It is not news that the coal sector in this country has suffered tremendously in recent years. Especially hard hit is the central Appalachian region, where a number of factors combined have had a devastating effect on production, jobs and the economy. These factors include federal regulations affecting coal production and use, higher production costs and decreasing market share of Appalachian coal by the switch from lower sulfur coal in favor of lowercost, higher sulfur coal from the Illinois Basin, as utilities have installed scrubbers to comply with Phase II of the 1990 Clean Air Act Amendments. Nationally, the lower cost of natural gas has been a huge factor affecting coal use. In Kentucky, for example, which exports to other states around 70 percent of its coal, those markets are disappearing, as utilities close coal units in favor of natural gas. This is a structural change in the electricity market, and one that will become more pronounced as federal greenhouse gas regulations are implemented.We often hear the phrase, "the war on coal." While there are certainly a number of market factors affecting coal production and use, this phrase captures a different element that is all too real. The attacks have come from environmental activist groups for many years; from some in the media and, in the last few years, from a White House administration that believes strongly in alternatives to coal. Then, there really is an alternative to coal in the form of the previously untapped unconventional gas reserves that allowed utilities to move away from coal.Coal mining will continue in this country. In fact, it appears that our production is holding fairly steady at about a billion tons a year. And predictions that I have seen indicate this will continue for the next few years. What impact the Environmental Protection Agency’s Clean Power Plan will have beyond 2020 is another question.What do you feel is the future of the minerals industry - near term and longer term?Our society depends on the future of minerals in this country being strong. Near term, we are going through some of the typical cycles. Having also been involved in aggregates during the last few years, the business follows government infrastructure projects, such as highway construction and public and private sector development. Those sectors are heavily dependent upon government spending and a strong economy. Increased spending in those sectors, which appears to be on the horizon, should provide additional market shares for aggregates."

Jan 1, 2014

By L. W. Saperstein, R. J. Sweigard, D. L. Simpson

Deep tillage is widely used as a means of alleviating excessive soil compaction. There has been some concern that the voids created by deep tillage may collapse before a more natural soil structure develops, resulting in recompaction subsequent to deep tillage A laboratory investigation was conducted to determine the feasibility of pneumatically injecting organic material into the voids produced during deep tillage in order to prevent any significant recompaction from occurring. Various amendments were injected into the soil during laboratory tests using a small-scale ripping and injection system. Measurements were made of selected soil proper Pies to evaluate the feasibility of this method.

Jan 1, 1994

By R. S. Olson

The operation of a series wash thickener-two stage filtration circuit determines the soluble loss in many hydrometallurgical operations A study of this circuit yielded expressions which permit calculation of soluble loss for almost any condition of operation. The soluble loss over a range of the circuit variables is presented to illustrate and evaluate circuit performance, The interrelation of factors affecting filter performance and some of the wash circuit, variables are quantatively described. Filter wash, which is governed by wash zone size, filter pulp level and filter feed pulp density, has the greatest affect on soluble loss. Excepting clothing blinding and flocculation the factors which decrease filter capacity also decrease soluble loss. Repulping with water, under some circumstances, can bean important means of soluble loss reduction. Water for primary filter wash, leach pulp density repulp density and wash thickener underflow density have little effect on soluble loss. The dilution of both o the filter pulps with wash solutions is suggested as a means of reducing soluble loss, and at the same, time, controlling the performance of the filters. Blowback and filter cloth blinding seriously increase soluble loss.

Jan 1, 1962

By D. J. Carpenter

Safe and successful mine closure represents a fundamental work element that needs to accommodate the geochemical conditions existing at the completion of the mining and ore processing effort. Given the interests in limiting costs and time associated with mine closure efforts enhanced prior understanding of the geochemical conditions likely to exist upon exhaustion of the economic reserves can provide important benefits. The purpose of this paper is to document the benefits associated with geochemical modeling and understanding how the ore formation process may impact mine closure efforts, using one ore deposit type as an example. Specifically, this paper will emphasize the geochemical processes leading to the formation of sandstone-hosted uranium roll-type deposits and how the resultant concentrations and distributions of ore and gangue phases need to be incorporated into understanding the geochemical conditions projected to exist at the end of mineral recovery efforts. The paper will describe the evolution of geochemical conditions leading to ore body formation and the geochemical effects induced by open pit mining and how these may be used to understand both the geochemical controls and constraints on residual mine water. In addition, a discussion will be provided on how these conditions may be simulated by solution equilibria and kinetic modeling to develop optimum approaches to achieve applicable closure standards. This paper will also discuss specific augmentations to existing industry standard solution equilibria and kinetic models and associated thermodynamic databases to maximize the predictive accuracy of the geochemical modeling results. The benefits of understanding the electrochemically reactive behavior of uranium and associated gangue phases and incorporating this behavior into mine closure efforts will be presented. The culmination of the benefits of the geochemical modeling will ultimately be the development of a sustainable approach to uranium mine closure that is based upon an engineered environment designed to return the ore body to stable geochemical conditions.

Feb 27, 2013

By Alan E. Isaacson

Extensive gravel deposits exist within a six-county area in the mountains surrounding the Salt Lake Valley, and in the mountain ranges to the west. The six-county area includes Davis, Salt Lake, Summit, Tooele, Utah, and Wasatch Counties. The majority of these are beach deposits from prehistoric Lake Bonneville. However, real estate development associated with a projected population increase of 54 percent over the next 20 years is expected to remove most gravel deposits in Salt Lake County from consideration for mining, forcing gravel operations to relocate from eastern Salt Lake Valley to the Oquirrh and Stansbury Mountains farther west. The gravels in these ranges are of lower quality and require additional processing to manufacture asphalt and concrete. Replacing gravel resources along the Wasatch Front with resources in the Oquirrh and Stansbury Mountains over the next 20 years has the potential to increase construction costs by nearly $1 billion. The majority of this cost (82 percent) is the result of increased transportation costs due to longer distances to market. The remainder of the cost is attributable to lower quality gravels that will require additional processing in the manufacture of asphalt and concrete. The following analysis and discussion does not take into consideration the amount of crushed stone that is currently being used in the construction industry in northern Utah, its use as a substitute for lower quality gravels, or as a factor in the base case projection.

Jan 1, 2001

By John P. Albers

During the 1950's and 1960's a program of geologic mapping of counties has been underway in Nevada by geologists of the U. S. Geological Survey and the Nevada Bureau of Mines. The aping has been done principally at reconnaissance scales, with more detailed work in local areas. Geologic maps are either published or open-filed for about a dozen counties at scales of 1:200,000 or 1:250,000. One by-product of the geologic mapping has been the recognition of about 80 Tertiary volcanic centers from which large or very large volumes of volcanic material ranging from rhyolitic to andesitic in composition have been erupted. For purposes of this discussion these are regarded as the major centers; the tally does not include hundreds and perhaps thousands of small rhyolitic domes and plugs and basaltic vents. About 15 to 20 of the 80 major centers are believed to be calderas ranging in diameter from 3 to 25 miles. Some have been described in the literature by geologists of the Nevada Test Site and others. However, the vast majority of the 80 centers have not been described in print, and we are indebted to our colleagues for locating them for us in many of the counties. Briefly, we would like to express our appreciation to the following people all members of the USGS unless identified otherwise: Robert Coast, who has identified the centers in Elko County; Ron Willden, Robert Yates, and

Jan 1, 1968

By J. Jonas, J. M. Harrington, K. Wangerud, S. D. Fundingsland, J. G. Harrington

EPA NRMRL Mine Waste Technology Program and Region VIII Superfund office are jointly conducting an in-situ technology demonstration at the Anchor Hill Pit Lake, Gilt Edge Mine Superfund site. The goal is to develop in-situ treatment cost/performance data for potential application in long-term water treatment/management at Gilt Edge and similar sites. The pit contained 77,000,000 gallons of pH 3water with elevated metals, sulfate, and nitrate. The Green World Science® patented process for in situ treatment was implemented to isolate and sequester metals; create stable long-term water quality and restore a sustainable ecosystem. COCs have decreased more than 99%, and dissolved discharge standards were attained.

Jan 1, 2004

By Len Harris

Webster?s Dictionary describes culture as: ? The totality of socially transmitted behavior patterns, arts, beliefs, institutions and all other products of human work and thought typical of a population or community at a given time. ? A style of social and artistic expression peculiar to a class or society. ? Intellectual and artistic activity. ? The art of developing the social, moral and intellectual facilities through education. The authors have nearly 100 years of combined experience in the mining industry working with and consulting to mining companies and companies engaged in the supply of goods and services to the mining industry worldwide. In this report, they present their experiences and ideas on the importance of cultural aspects in the successful development and implementation of mining ventures. Their suggestions on how to handle culture shock will be of interest to expatriate managers, operators, social workers, and engineering and construction personnel posted to overseas operations, as well as to nationals posted to other parts of their own country.

Jan 1, 2008

By J. A. Matar

Mineralization features at the Bajo La Alumbrera porphyry copper-gold deposit are discussed as they affect gold leaching and copper flotation behavior. Alteration-mineralization geological blocks are assigned in the zoned body, and each required its own geostatistical model. They extend horizontally outward from potassic to the phyllic-propylitic boundary, vertically from surface down to 300 meters, and include oxide, secondary enriched, and hypogene mineralization. Copper and gold values are calculated geostatistically from assays and all available geologic-mineralogic information. Reserves are classified for each geologic block and for each open-pit bench into leach or float ore according to metal grades, geologic characteristics, and supergene-hypogene relations. Finally ore extraction behaviour is briefly described, grouping gold and copper reserves into metallurgical families.

Jan 1, 1986

By Nathaniel Arbiter

Flotation’s earliest patent was issued in 1860. However, the process was first applied commercially in Australia until 1904, and in Montana in 1911. Major advances followed both in reagent treatment and in cell design, with resulting process improvements. Mechanical cells have seen the widest use and with the major increases in plant capacities (Fig. 1) their volumes have also increased (Fig. 2). In 1991, the principal use for the process was to produce copper concentrates for smelting. It was applied to 243 Mt (268 million st) of copper ore. The total of all ores floated that year was 426 Mt (470million st). In 1997, US mines produced 257 Mt (284 million st) of copper ores for flotation, yielding1.75 Mt (1.94 million st) of copper.

Jan 1, 2000

By John Carr

The tremendous growth in grinding mill size and horsepower during the '70s demanded advancements in gear cutting technology and equipment for the '80s. Computers are used as an aid in the design and selection of the mill drive system; sophisticated computer graphics are used to create manufacturing drawings; and a new generation of gear cutting machines are used to manufacture the gears. These new gear cutters can generate-cut gears over 40' (12.2 m) in diameter at an AGMA quality level exceeding the currenty acceptable standards. The precision of the resulting gear assures maximum tooth contact, which will result in longer gear set life.

Jan 1, 1981

By Key Rosebrook, Jennifer Laggan, Ashley Rivera

Significant quantities of waste rock at abandoned uranium mine (AUM) sites in the western United States require removal from steep slopes exceeding 45 degrees in remote locations. This prevents the use of traditional excavation equipment and poses significant challenges for safe, effective material removal. A pilot study was conducted using a spider excavator to demonstrate the feasibility of removing waste rock and transporting it to areas where conventional equipment could be employed. The spider excavator was evaluated for its effectiveness in excavation, material movement and control, container usage, dust mitigation, and ensuring human health and environmental safety. The study established constructability and engineering parameters for implementing spider excavators in these challenging environments. Key outcomes include the preservation of existing vegetation, improved waste movement control, and enhanced safety measures for workers, nearby residents, and the environment.

Feb 1, 2025

By R. B. Massy-Greene

Project engineering and development is a process of optimisation of capital, operating and financial costs, and extraction rates in the light of current and forecast economic conditions for the sale of the product. The aim of the process is to maximize financial returns to the sponsors (project owners) within many often conflicting constraints. Thus, the sponsor's engineering and financial staff have a common goal, with performance measured in financial terms. Consequently, each group must be aware of, and responsive to, the constraints imposed upon the other. For financial staff, the increasing size and complexity, and escalating capital costs of new ventures have required them to seek finance in larger amounts, and by non-traditional methods. In addition, senior management are requiring indications of the availability of finance as a pre-requisite to a decision to commence project development activities.

Jan 1, 1982

By T. Dunn

FMC Corporation has achieved a significant cost reduction through a new proprietary solution mining and processing technology at its Green River, Wyoming Soda Ash Facility. In the first phase, completed in October 1995, trona ore is dissolved, recovered and processed with the new technology, and then fed into an existing refining plant, replacing dry mined and calcined trona ore. The second phase, completed in April 1996, produced a fmal high purity product and increased capacity by 635,000 t/a (700,000 tpy). Both phases were completed under budget and well ahead of schedule.

Jan 1, 1998

By Bruce E. Kester

The concurrent observation of the phenomena of alkali-aggregate reaction and development of efficient dust collection systems on rotary kilns made mandatory the process modifications to produce low alkali cements. Such low alkali cements as were available prior to these recent changes were either the rare result of low alkali raw materials, the loss of alkalies with dust loss from the kiln stack, or in some instances by the use of CaC12 in the kiln feed to increase volitalization of the alkalies and their subsequent loss or discard with the normal dust emission from the kiln. The relative slowly soluble nature of natural occurring alkali minerals in cement raw materials as compared to the very soluble nature of the alkali salts as present in cement kiln reaction products, either in clinker or in dust emission led to the development of the water leaching system. Two distinctly different problems of leaching are created by the two major systems of portland cement production, the wet and dry processes. The wet process is characterized by moderate dust loads and concentration of soluble forms of alkali in the dust. Further the return of the leached dust slurry does not materially change the characteristics of kiln feed on reintroduction and subsequently does not materially influence kiln operation. The dry process differs in high levels of dust emission and the presence in the collected dust of large amounts of unreacted kiln feed with its sparingly soluble alkali minerals. In the dry process reintroduction of leached dust slurry changes the dry process to what may be classed as a damp process. This change results in some decrease in kiln capacity and creates conditions of operation which are uncommon to either the wet or dry process.

Jan 1, 1963

By G. M. Bernard

An overview presentation of the fast-track start up of Cerro Colorado, a new copper heap leach project in Chile's Atacama' desert. A brief explanation 'of location of the property, exploration history, geol-ogy, reserves and development are presented. The overview includes mining, crushing, agglomeration, and the solvent extraction-electrowinning recovery process. Challenges and requirements specific to heap leach systems will be addressed and analyzed. A detailed description will be given of the mobile heap leach conveying and stacking systems used in the building of heaps for on-and off-pad operations.

Jan 1, 1995

By Ellsworth R. Spencer

An assessment of U.S. western hardrock miners? noise exposures was conducted as part of a multi-year National Institute for Occupational Safety and Health (NIOSH) survey of noise exposures in each sector of the mining industry. Noise from selected mining equipment and operator noise exposures were measured, analyzed and tabulated for dissemination to the participating sites and are being used to direct NIOSH research and interventions to address the greatest noise hazards. Eighty-two noise dosimeter measurements were obtained, along with time-motion studies as the miners operated hardrock mining machines. Of the operators, 96% had daily noise doses that exceeded the U.S. Mine Safety and Health Administration?s (MSHA) permissible exposure level. The average gold miner dosages while operating the following equipment were: haul trucks - 261%, load-haul-dumps (LHDs) - 235%, single boom drills - 221%, bolters - 214% and dual boom drills - 163%. The worst exposure level was a silver miner with a daily dose of 873%. Time-motion data showed that this miner?s exposure accumulated most rapidly while operating a jackleg drill. These results will be used to help prioritize noise control development by NIOSH and other partners.

Jan 3, 2010

By H. K. Lin

Deepwater discharges of sulfide flotation tailings have been practiced for several decades. Oxygen penetration and organic matter content in such environments are the two major factors that determine their reduction-oxidation condition and hence the rate of sulfide mineral dissolution under such discharge environments. In this study, the effects of solution redox potential and pH on the dissolution of some heavy metals from sulfide flotation tailings were examined. Zn, Pb and Cu concentrations in solution were all higher at a higher redox potential and lower pH. Dissolved Zn concentrations reached 100 ppm even at a low redox potential of 105 mV and near neutral pH after 33 days. Pb concentrations were below 2 ppm at 105 mV and near neutral pH after 165 days. At 105 mV, the Cu concentrations were below 0.2 ppm at near neutral pH after 165 days. At pH 2.3, the Fe concentrations were higher at 420 mV than at 105 mV. But at pH 6.8, the Fe concentrations were lower at 420 mV than at 105 mV, due to the oxidation of Fe2+ to Fe3+ and the subsequent precipitation of ferric hydroxide. Arsenic concentrations in solution were all less than 0.002 ppm. For Zn, Cu and Fe, no significant differences were observed between the tests in solutions prepared using seawater and those using distilled water. However, Pb concentrations reached higher levels in solutions prepared using seawater.

Jan 1, 2009

By Roberto J. Guardia, Ted Lewtas, Peter Rasmussen, Klaus Winkler

As part of the Lake Fort Smith Water Supply Dam Enlargement project, located in northwest Arkansas, microtunneling methods were used to install two side-by-side,1.53m (60-in) inside-diameter steel pipes between the intake structure shaft and the lake. The 46.6 m- (153 ft-) and 41.7 m- (137 ft-) long tunnels were excavated in Pennsylvanian sedimentary bedrock ranging from coarse sandstone to siltstone and shale-like claystone. The intake tunnels were constructed 18.3 m (60 ft) below lake level from the dry shaft. Special installation methods and procedures described herein were used to complete the lake taps. Installation difficulties that caused minor delays are also reviewed. After the excavation of the Intake shaft was completed, the two lake taps were installed in approximately ten weeks with the same microtunneling machine.

Jan 1, 2005

By D. R. Spears

The U.S. Bureau of Mines has had an ongoing interest in developing new reagent schemes for floating Stillwater, MT, chromite ore. Previous reagent schemes have been unsuccessful in achieving complete separation, primarily because little is known about the surface chemistry of the minerals in this ore. In order to design a rational reagent scheme, a study of the binding of various functional groups (R = -H, -OH, -CO2H, -NH2) on the two components (chromite and forsterite) of the Stillwater chromite was undertaken. Electron Paramagnetic Resonance (EPR) Spectroscopy was used to determine the adsorption isotherm, from a cyclohexane solution, of spin-probes which contained the functional group of interest. This was complemented by studies of the saturation surface coverage of the spin probe on the two minerals. In each case, more sites existed on chromite than forsterite; however, the forsterite sites were more strongly binding for each functional group. The results are discussed in terms of their implications for flotation.

Jan 1, 1994