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By Richard C. Fox

"Why geophysics? We will have to drill anyway." Reliance on geophysical methods for detailed target appraisals will increase as direct surface evidence becomes more subtle. This will create a need for more effective and efficient geo- physical programs. Numerous computer-based techniques that deal with a broad range of geophysical problems are described in the literature. The purpose of this chapter is to provide a framework for the systematic application of these techniques to effect an overall optimization of the geophysical appraisal. The concepts described are not technique specific, but should serve as a guide for increasing the effectiveness and efficiency of any geophysical program. Fig. 1 shows a generalized flow chart of the major aspects of the program described. The three main subdivisions of a 'geophysical program are discussed: (1) survey design, (2) data processing, and (3) data interpretation. Detailed flow charts, outlining the goals, the requirements for meeting the goals, and the steps followed within each subdivision are presented at the beginning of each section. The objectives and type problems of each subdivision are defined, followed by a description of applicable computer methods. . References are cited that give a general cross section of computer techniques available in the literature, and examples are given in each subdivision to demonstrate basic concepts and the use. of computers in solving the type problems.

Jan 1, 1979

By Robert G. Ditchburn

The Mariana arc is an ~1,400-km-long intraoceanic arc that marks the southern extension of the Izu-Bonin arc, and is host to 62 ?volcanic centers? of which at least 27 (21 submarine) are hydrothermally, or volcanically active. A surface ship cruise in early 2003 mapped the distribution of hydrothermal plumes emanating from these centers, followed by remotely operated vehicle (ROV) cruises with ROPOS in 2004 and Jason II in 2006. With the exception of one volcano (East Diamante), none of the vent sites visited by the ROVs were host to sulfide mineralization. Rather, they were characterized by high sulfidation mineral assemblages dominated by native sulfur. The sulfur was seen marking the vicinity of vent sites, or as sulfur ?chimneys? (e.g., NW Eifuku and Nikko), or more spectacularly as ?lakes? of molten sulfur, either occupying the summit crater of the volcano (e.g., Nikko), or perched on the flanks of the volcano, near the summit (e.g., Daikoku). Gas (H2S and CO2) was discharging through the molten sulfur. Evidence for these lakes to have either been substantially ?deeper? in their recent past (e.g., Nikko), or existing at other volcanoes (e.g., Seamount ?X?) is given by remnant ?pillars? of native sulfur that are reminiscent of rock pillars in lava lakes found along mid-ocean ridges.

Jan 1, 2008

By E. Yigit

Hydrometallurgical production of zinc from concentrates is generally carried out by H2SO4 leaching. For the smooth operation of this process, some harmful components must be removed from the leach solution before the electrolysis stage; MgO is one of these compounds. Zinc concentrate samples from the Mount Isa mines were used in leaching tests. Leaching tests with an aqueous solution of H2SO4 and SO2 gas were carried out at various temperatures, pH levels and leaching durations. While duration and the pH value of the solution were effective parameters in H2SO4 leaching, temperature and pH were more effective in SO2 leaching for the removal of MgCO3 and CaCO3. Removal of MgCO3 and CaCO3 was generally achieved at low pH values. The results show that SO2 gas can be a good alternative to sulfuric acid in the leaching of MgCO3 and CaCO3

Jan 1, 2010

By D. W. Wu, M. T. Haque

A novel impedance probe was commissioned specifically for capturing fast dynamic information about filtration processes. It provides an attractive alternative to more complex measurement techniques in situations where the slurry system is primarily one-dimensional. The probe can monitor mudline, slurry densification and drainage. Dynamic variations in cake permeability are obtained by combining dynamic mudline information obtained with the probe and filtrate rate data derived from a leaf test apparatus. The measurements are reviewed in relation to micro structural measurements obtained on iron ore filter cakes. The practical significance of these measurements for optimization of the filtration process is discussed.

Jan 1, 2002

By Gregory Rumbaugh, Christopher Mark

Recent pillar collapses have caused five large airblasts in underground U.S. limestone mines. One of these events injured three miners, but all of them put many other miners at risk. To better understand the hazards, Mine Safety and Health Administration (MSHA) conducted a comprehensive review of the international literature on airblasts. More than 40 airblast cases have been documented, in a wide variety of minerals. Experience shows that miners that are in the direct path of the air as it moves towards the mine exits are at the greatest risk. The paper describes a risk management methodology that can be used to evaluate the level of hazard throughout the mine and aid in the selection of controls to reduce the risk. The paper concludes with a detailed case history of an actual pillar collapse and airblast.

By Mark J. Logsdon, Barbara Basse

Mississippi Valley Type Pb-Zn deposits are widespread in the midcontinent U.S. and have been mined from the 1800's to present. Some tens of thousands of acres of mined land in the Tri-State District have been designated as Superfund sites as a result of surficial mine wastes and ground waters with elevated levels of metals. EPA considers the surficial mine wastes to be hazardous and a major source of acid mine drainage fAMD) that degrades water resources and threatens human health and the environment. To mitigate potential risks at one site near Galena, Kansas, a group of mining companies who had been identified by EPA as Potentially Responsible Parties IPRPs) proposed subgrade disposal of the mining wastes in shafts and subsidence features. However, this proposal was challenged by the Agency on grounds related to AMD and the potential for degradation of ground water quality. The PRP team developed a program of materials characterization, laboratory-scale leaching, and finally large-scale, pilot testing in the field. Static and dynamic leaching tests at both laboratory scale fusing artificial rainwater under both variably and fully saturated conditions) and field scale (using pH 4.5 ground water) showed that the surficial wastes do not produce acidic leachate and are not a long-term source of metals. Laboratory chemical and mineralogical tests show that the mine wastes contain substantial carbonate, but very limited iron sulfides, consistent with the leach test results. EPA "characterization" tests fEP Toxicity and TCLP) compare very poorly with tests simulating the expected leaching conditions. While these tests would classify the surficia1 wastes as "hazardous, they do not characterize the behavior of the high-volume, low-concentration, coarse-grained materials with respect to environments and disposal options of interest. To be meaningful, characterization of mining wastes must be performed in a manner that simulates the environmental conditions that are actually of interest with respect to a specific decision, such as subgrade disposal in the saturated zone.

Jan 1, 1991

By Alexander May

In its role of providing technology to promote the efficient use of minerals and mineral process waste, the U.S. Bureau of Mines has conducted research at: its Tuscaloosa Research Center to identify and develop high volume uses for phosphogypsum. Mixtures containing a maximum of 50 percent phosphogypsum, 6 to 10 percent lime, and the remainder fly ash had compressive strengths as high as 4,800 psi. The effects of the mounts of phosphogypsum, lime, and fly ash were investigated. Also, the effects of fly ash to lime ratios were studied.

Jan 1, 1983

By L. K. Holder

The White King / Lucky Lass Superfund site consists of two former uranium mines in south-central Oregon. The remedy included consolidating two large mining overburden stockpiles that contained low levels of radioactivity and heavy metals by moving over 700,000 cubic yards of material and then capping the combined stockpile. An innovative armored cap design was used to minimize the stockpile footprint and thereby prevent disturbing existing wetlands. In addition, the stockpile was designed to merge into the surrounding topography. The remedy also included stream restoration and development of new wetlands. The stream was returned to its pre-mining channel, with the addition of hydraulic features to create new wetlands. The wetlands have greatly enhanced the ecological value of the remedy and the site.

Feb 23, 2014

By Bernard L. Cohen

INTRODUCTION The most serious occupational radiation episode in U.S. history was the exposure of uranium miners to radon daughters in the 1945-1968 time period. Although the maximum permissible dose at that time was 12 WLM (working level months) per year, average exposures were several times that figure, and ten times higher exposures were not uncommon. Starting in the early 1960s, mounting epidemiological evidence appeared for an excess incidence of lung cancer among these miners; up to 1974, there was an excess of 134 cases (159 observed vs 25 expected) among the 4000 in the group under study (NAS-1980). When this excess became apparent, the Federal Government took jurisdiction, greatly tightened enforcement, and in 1969 lowered the maximum permissible exposure to 4 WLM per year. These standards were met largely by a great improvement in ventilation. As a result of these measures, average miner exposures were reduced 5-fold from 1965 to 1968 and by another factor of 3 by 1970. In 1978, the 4 WLM/year maximum permissible exposure was exceeded by only 37 of 7500 underground miners, for only 16 wars it exceeded by more than 25%, and for only 8 was it exceeded by 502 (AIF-1980). The average exposures to the various groups are listed in Table 1. We see that the average exposure for all miners was 1.03 WLM, and for those who worked essentially full time underground it was 1.45 WLM. For purpose of later discussion, it will be convenient to choose a single value for average exposures. In view of the fact that employment situations and job categories are bound to vary over a lifetime of work, we take this to be 1.3 WLM/year. The purpose of this paper is not to dwell on history, but rather to address the question of whether or not this present situation is satisfactory. This question was considered recently by a study group under the auspices of National Institue of Occupational Safety and Health (NIOSH-1980) and it answered the question in the negative, concluding that the maximum permissible exposure should be substantially reduced. However, their arguments were incomplete and were lacking in perspective. The principal thrust of this paper is to provide some of the material overlooked. RISK TO URANIUM MINERS FROM RADON EXPOSURE In order to quantify the risk to uranium miners under present working conditions, it is first necessary to estimate the risk of lung cancer per WLM of exposure. The most straightforward way of doing this is to use the data on the group of uranium miners under study. These are listed in Table 2 for 8 exposure ranges and for the total group (NAS-1980). If all data are given equal weight, the risk is seen to be 3.5 x 10-6 per year per WLM. Much can be said in favor of using this value for the risk as dose independent; it is within one standard deviation (SD) of the observations in 5 of the 8 dose categories (as expected from the definition of SD), and within 2 SD for all 8, and for the three cases differing from the mean by more than one SD, two are above and one is below. However, the uranium miner exposures in the present situation will be far below those covered in Table 2, so it is worth considering the possibility that the risk differs from this at low doses. From the last column of Table 2 we see that the experience from all exposures below 600 WLM indicates a risk higher than the mean for the entire group by more than two standard deviations (the value 600 WLM in this comparison was deliberately chosen to maximize this deviation; for exposures below 360 WLM and 840 WLM, the excess is only 1.0 and 1.6 standard deviations respectively). In view of this tendency for the risk to be higher at lower dose, we will take the risk to be 5.0 x 10-6 per year per WLM in what we will refer to as model A. This risk estimate is based entirely on exposures much [higher] than those that will be experienced by

Jan 1, 1981

By V. F. Swanson

A mathematical model is presented which allows the free or hindered settling velocity to he calculated for any size or- shape particle in any fluid, and at any percent solids up to the maximum. The validity of the model is supported by comparing calculated velocities (or viscosities) with measured values for 1073 data points contained in 80 sets of data encompassing a range of Reynolds’ numbers, from 0.002 to 770.000. The average error was 0.69%, with an average standard deviation of 6.65%. The derivation of the model is too lengthy to include in this paper, which will specifically present the application of the model to the free settling of minerals and spheres, prediction of the friction factor in wind tunnel tests, the viscosity of suspensions of spheres, the hindered settling of mono-sized spheres and closely sized minerals, and the settling of large spheres in suspensions of small spheres.

Jan 1, 1990

By Frank F. Aplan, Edward C. Jr. Dowling, Richard R. Klimpel

Thirteen kinetic models that mathematically describe the flotation process have been statistically evaluated for the flotation of copper, lead and zinc ores. Comparisons have been made for a variety of circuits involving roughing, cleaning, scavenging and regrind followed by cleaning. Variations in collectors, frothers, depressants and activators have been considered. Based on the statistical criteria used for the evaluation, and the reagent, circuit and ore variations studied, the most reliable flotation models have been identified and subsequently used to characterize the metallurgical results.

Jan 1, 1986

By P. W. Finck

Detailed mapping, using a large diameter diamond-drill in conjunction with high resolution reflection seismics, has increased known resources of kaolin clay and glass-grade silica sand from scattered deposits generally < 1 km2 to large areas of Cretaceous valley fill up to 130 m thick. Detailed chemical and physical analysis of drill core is presently underway. Silica sand deposits intersected in this study are up to 99.4 % SiO2 without beneficiation. Light grey to white kaolin clays identified by XRD and DT A have concentrations values (without beneficiation) up to 47.28% SiO2, 37.44% Al2O3, 0.45% Fe2O3, 0.49% K2O, 0.07% Nap, 0.07% CaO and 0.39% MgO.

Jan 1, 1996

By A. Iannacchione

Most legacy drift mines entered the coal reserve from outcrop and developed up-dip. The Surface Mining Control and Reclamation Act of 1977 changed this way of mining, requiring all new mines with acid- or iron-producing coal seams to be designed so as to prevent gravity water discharges from the mine. This Act requires engineered barriers to contain the mine pool. In many cases, mine layout designs focus primarily on the size and hydraulic performance of the un-mined coal barrier between the up-dip mine pool and areas where down-dip surface discharge is possible. In other cases, designs focus on preventing discharges from barriers contained within the strata surrounding the mined coalbed. This paper focuses on a detailed analysis of the factors responsible for preventing mine pool discharges to surface waters. Important factors include: mine layouts, mining methods, hydraulic head and conductivity, and geology. While the exact causes for the successes and failures could not always be determined, reasonable mechanisms are presented.

Feb 23, 2014

By E. Woodburn, Harrison R. Cooper, R. Putman

The key to concentrator automation is practical means for obtaining continuous assay data from concentrator streams. The technique most successfully used is x-ray fluorescence analysis. The practical reality of on-stream x-ray analysis has been achieved through effort over the past twenty years, marked by an occasional breakthrough, but more typically a step-by-step development to which many individuals and organizations have contributed. The net result of this progress is the present capability to install on-stream x-ray analyzer systems on a turn-key basis. It is now possible to provide all components of an x-ray analysis system as a completely engineered unit which can be put into immediate use, minimizing needs for specialized application know- ledge to benefit from continuous assaying in process control. The economic factors which influence the choice of system and limitations of the x-ray fluorescence technique for slurry analysis are reviewed.

Jan 1, 1976

By J. Klemenic

This paper presents an analysis of gold production and prices over an extended period. Production patterns are provided for the world as a whole and for the five major producing countries. Gold prices as a function of interest rates, as measured by municipal bond rates, are given for the period 1947 to the present. World gold production has had a phenomenal increase since 1980, with the exception of South Africa, all major producing nations participated in this increase, even though the price of gold generally has been decreasing since the high level attained in 1980.

Jan 1, 1993

By S. Veeramasuneni

The interaction of soluble salt particles in their saturated brines is of interest from both a fundamental and practical perspective. The state of dispersion/aggregation of alkali halide particles as determined by optical microscopy can now be described based on non-equilibrium electrokinetic measurements for alkali halides. These results indicate that the sign of the surface charge has a significant effect on the extent of particle dispersion/aggregation. Atomic force microscopy (AFM) is now being used to directly measure the interaction forces responsible for the stability of these alkali halide aggregates observed in optical microscopy studies. These experimental results can be explained based on the interfacial polar interaction theory. In this regard the nature of such particle interaction forces at high ionic strengths are examined to improve our understanding of these systems.

Jan 1, 1997

By D. R. Taylor, R. G. Goss

The use of clay granules as carriers for pesticides dates from the early 1940&apos;s and by the present day represents a business conservatively estimated at between 200 - 300 thousand tons / year in the U.S. alone. Aside from economic and specific target pest efficacy advantages, the use of clay granules as pesticide carriers also delivers a number of environmental benefits which will be reviewed. Topics to be discussed will include: 1) drift control (versus liquid sprays), 2) mobility (in the environment), 3) worker safety, and 4) transportation (spill) safety.

Jan 1, 1999

By Francois E. Heuze

This paper summarizes the geomechanics programs conducted in two hard rock underground mining operations in the Western United States, between 1966 and 1981. The two projects were directed towards understanding the behavior of the rock masses, at the scale of the caverns. To this end, the emphasis was put on large scale field measurements, complemented by limited laboratory testing. The results of these observations were used to build realistic finite element models of the underground chambers. In the marble mine, at Crestmore, California, the models were applied to the structural optimization of the room-and-pillar pattern. In the granite mining, at Climax, Nevada Test Site, the models explained some unusual stress changes observed during excavation. Based on the large number of geomechanical techniques employed, specific conclusions and recommendations are offered regarding the quality, applicability, and usefulness of the various methods. The two case histories clearly indicate chat numerical models are extremely useful for a detailed understanding of the structural behavior of mine openings. To be realistic, these models must be based first and foremost on large scale field observations. The lessons Learned on these two projects also are directly applicable to the design and analysis of nuclear waste repositories in hard rocks such as basalt, granite, and welded tuff.

Jan 1, 1982

By Ken Goering

"Bridgestone Americas opened the company’s first U.S.-based giant off-road radial (ORR) tire plant in November. The 139,000-m2 (1.5 -million-sq ft) plant, located on a 222-ha (550- acre) site in Aiken County, SC, will produce radial tire products, including 157-cm (63-in.) tires, used on mining and aggregate haul trucks.The plant, announced in 2011 as a $970-million investment, represents the largest investment that Bridgestone has made in the United States, and is also the single largest investment ever made in South Carolina. Although it had already been producing tires for a few months, the plant officially opened with a ceremony in November 2014, attended by South Carolina federal, state and local elected officials, as well as Bridgestone personnel from the United States and Japan. Prior to the Aiken County plant’s construction, all of Bridgestone’s giant ORR tires were manufactured at its Shimonoseki and Kitakyushu facilities in Japan.Kurt Danielson, president of Bridgestone’s U.S. & Canada Commercial Group, said the facility was built to primarily serve the North American mining and aggregate industries in a more efficient manner. "It’s a real change for us," he said of the U.S.-based plant at its opening ceremony. "This allows us to have a true global presence."The Aiken County plant is intended to allow Bridgestone to meet customer demand for ORR tires, Danielson said. "It really frees up our other plants in Japan to service the rest of the world, allowing us to serve our customers faster," Danielson said. "As soon as we build (a tire), we can have it to our customers."Tires manufactured at Bridgestone’s Japanese plants could spend up to a month in transit to the American continents; from initial mixing of the rubber and other compounds to being warehoused, tires manufactured at the Aiken County plant can be ready to ship in four to five days.Danielson said most of the tires built in Aiken County will be used by customers on the American continents. "We will export," he said, "but our desire is to use as much capacity as we can for the Americas."Ground was broken for the facility inSeptember 2011, when commodity prices were much different than today and global demand for tires had skyrocketed."

Jan 1, 2014

By K. L. Myers, R. Espell, C. Deringer

Construction of the AA Pad reclamation was completed in the fall of 2000. Seeding of the ET cover began in the late fall of 2000 and continued through May of 2001. On Saturday afternoon, June 1, 2002, a large, very localized thunderstorm struck the reclaimed AA Pad site. Eyewitnesses present at the time described a dark storm cloud parked above the site for less than half an hour. Average rainfall intensity was measured to be 122 mm (4.8 inches) per hour and peak rainfall intensity was estimated to be 213 mm (8.4 inches) to 259 mm(10.2 inches) per hour. At the time of the storm, the construction was less than two (2) years old and the vegetation had only a single season of growth. The entire period from the end of construction until the date of the storm was a drought period with below normal precipitation. Other than a few small snowmelt events, there was no precipitation event large enough to produce any significant flow in the channel network. Therefore, the very first significant runoff event was the extreme event of June 1, 2002. The storm essentially represents a large-scale field test of the design concepts used at the AA Pad site. Shortly after the storm, data was collected and analyzed with the intent of learning as much as possible about the performance of the cover system design with the expectation that the newly acquired knowledge might be utilized in future designs to further improve the performance of similar cover systems during extreme events.

Jan 1, 2003