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By Robert A. Cummings, Madan M. Singh

In April 1984 a subsidence depression formed directly beneath a two-story frame residence, near Linton, IN, causing 2 ft of separation between the floor and walls, and damaging both the foundation and interior of the building. The Office of Surface Mining undertook the rehabilitation of the area under its emergency response program. This paper describes the investigation performed to determine the cause, severity, and extent of the problem. Abandoned mine workings were found approximately 55 to 60 ft below the house. Based on the findings, remedial measures were prescribed. An abatement program consisting of grouting the mine voids was recommended, and specifications prepared. These were implemented, and the area has been successfully stabilized.

Jan 1, 1986

By Paul Russell, M. M. Kimberley, Erick F. Welland, Louis Cope, C. C. Mosher, William M. Shepard, William C. Larson, Graham Closs

Exploration activities in 1980 felt the effects of unstable economic conditions and oscillating metal prices. In the cyclical, boom-or-bust precious metals and uranium markets, precious metals activity flourished and uranium was definitely in a slump. By November last year, the price for vellowcake was down nearly $20 from two years earlier. Many mining and milling operations closed, particularly in Wyoming, New Mexico, and Colorado. Decreasing emphasis on nuclear power continued to impact the market, as did the Three Mile Island accident of 1979. Earlier forecasts estimated that 10 to 12 reactors would be ordered per year by US utilities throughout the 1980s, but current forecasts suggest that it may be 1983 or 1984, or even later, before any new US plants are ordered, according to Thomas A. Boyden, vice president of Nuclear Exchange Corp. "Without those new plants, the consumption loss to industry is 4 to 5 million pounds (1.8-2.3 kt) of uranium per year. The cumulative loss to the industry is currently estimated at 25 to 30 million pounds (11.3-13.6 kt)," Boyden said in a May 1980 presenta¬tion. Despite the plunging market, there were a few notable uranium explora¬tion programs: •Exxon expanded uranium exploration in New Mexico, where the company reportedly took preliminary steps toward acquiring mineral rights to a 22-km2 prospect, 19 km south of Santa Fe. • Mountain States Resources began the second phase of an exploratory drilling program on its Sinbad/ Solo prospect in Utah. • Also in Utah, Cotter Corp. drilled its first exploratory hole in the Dirty Devil River district. Exploration for precious metals in 1980, however, appeared to tend toward the opposite extreme. High prices sparked near feverish searches in Alaska, California, Colorado, and Nevada. Numerous mines abandoned years ago were revived with some signs of success. Significant gold finds were reported in California and Nevada: • Homestake Mining Co. announced a gold discovery in California estimated to contain over 5 Mt with an average grade of about 5.8 g/t. Because the deposit consists of finely disseminated particles not visible to the eye, many speculate that prospectors bypassed the area during the 1849 California gold rush. • Newmont Mining Corp. discovered two gold ore bodies-Maggie Creek and Gold Quarry. Maggie Creek reportedly contains an estimated 13.7 t of gold in 4.3 Mt of ore, and Gold Quarry contains about 31.1 t of gold in 9 Mt of low grade ore and 2.3 Mt of higher grade ore. Highlights of this year's exploration review include articles on the modest growth recorded in geophysical activity, technical developments in exploration geochemistry, the variety of new instruments being tested or made available for exploration, and a state-by-state exploration review for the year.

Jan 5, 1981

By M. Mikolás, L. Pomothy, K. Špakovská, M. Vanek

"Enterprises are faced with increasing economic competition and managers are obliged to look for methods that will ensure a competitive edge in their companies’ markets. These methods include managerial concepts that employ common sense and are low cost. One of these approaches is the KAIZEN methodology, of Japanese origin; kaizen means continuous improvement (CI) when translated. A mining company, despite some of its idiosyncrasies, is just an enterprise where the application of KAIZEN can be advantageous. The company investigated, OKD, is the only domestic producer of hard coal in the Czech Republic and operates four mines that produce 11 Mt of coal annually. The OKD management team opted for KAIZEN as their principal method of continuous quality improvement. This paper suggests ideas for development and application of processes that provide for continuing improvement of production and management. The authors have taken the OKD Company to be their benchmark in the field of mining activities. The paper also focuses on possible difficulties accompanying the introduction of CI sustainable methods. Three years of application of CI methods has increased the income of the company by almost US$38.1 million, which provides a strong argument for continued application."

Jan 1, 2015

Current mine production planning, scheduling, and allocation of resources are based on mathematical programming models. In practice, the optimized solution cannot be attained without examining all possible combinations and permutations of the extraction sequence. Operations research methods have limited applications in large-scale surface mining operations because the number of variables becomes too large. The primary objective of this study is to develop and implement a hybrid simulation framework for the open pit scheduling problem. The paper investigates the dynamics of open pit geometry and the subsequent material movement as a continuous system described by time-dependent differential equations. The continuous open pit simulator (COPS) implemented in MATLAB, based on modified elliptical frustum is used to model the evolution of open pit geometry in time and space. Discrete open pit simulator (DOPS) mimics the periodic expansion of the open pit layouts. Function approximation of the discrete simulated push-backs provides the means to convert the set of partial differential equations (PDEs), capturing the dynamics of open pit layouts, to a system of ordinary differential equations (ODEs). Numerical integration with the Runge-Kutta scheme yields the trajectory of the pit geometry over time with the respective volume of materials and the net present value (NPV) of the mining operation. A case study of an iron ore mine with 114 000 blocks was carried out to verify and validate the model. The optimized pit limit was designed using Lerchs-Grossman?s algorithm. The best-case annual schedule, generated by the shells node in Whittle Four-X yielded an NPV of $449 million over a 21-year mine life at a discount rate of 10% per annum. DOPS best scenario out of 2 500 simulation iterations resulted in an NPV of $443 million and COPS yielded an NPV of $440 million over the same time span. The hybrid simulation model is the basis for future research using reinforcement learning based on goal-directed intelligent agents.

Jan 1, 2008

By J. W. Thompson

CONSTRUCTION OF STATUTE-SALE BY ENTRYMAN. The timber and stone act (20 Stat., 89) does not forbid an entryman from alienating his interest in his claim; but the act makes illegal any prior agreement by which the entryman acts for another in the purchase. Worden v. United States, 204Fed., 1, p. 4, April, 1913. ASSUMPTION OF DEBT BY GRANTEE-LIABILITY TO CREDITOR OF GRANTOR. A grantee of a mine who agrees to pay the grantor's debts in part payment of the purchase price of the mines becomes to that extent the principal debtor, and the grantor becomes the surety, and the grantor's creditor may in equity enforce his claim against the grantee of the mine, and the grantor in such a case is not a necessary party. Silver King Coalition Mines Co. v. Silver King Consolidated Mining Co., 204Fed., 166, p. 169, April, 1913. RIGHT OF COTENANT TO MINE AND SELL. A cotentant in exclusive possession' of mining property who extracts and sells ore is entitled to charge against the proceeds of the sale the reasonable and necessary expense of its extraction and marketing, as in such case the cotenant is not a trespasser.

Jan 1, 1914

By B. E. Warren

Jan 1, 1965

By T. Wang

A new generated NaNO3 ? NaNO2 ? KNO3 ternary thermal energy storage system which has low melting point as 124°C and high specific heat capacity was studied for the short and long?term thermal stability by using the Thermogravimetric Analyzer (TGA). Based on the actual working condition of molten salt in solar two, the simulated cyclic thermal stability measurement was also conducted. The ternary system demonstrates excellent short ? term thermal stability and thermal reliability after cyclic heating and cooling processes. However, in the long ? term as well as the simulated cyclic stability measurement, large amount of weight loss was observed. Moreover, the stepwise long ? term isothermal study reveals that below 440°C the weight change is minimal and this temperature is viewed as the upper limit temperature of thermal stability for this ternary system. To determine the lost phases at high temperature above the upper thermal stability limit, techniques such as XRD and SEM are used to compare the condition of the salt mixture before and after the long ? term thermal stability study. On the basis of the comparison, it can be concluded that the major weight loss was due to the decomposition of sodium nitrite.

Jan 1, 2012

By Greg Barnes

Agenda ? The Mining Stock Life Cycle ? Current Environment ? Valuation ? Golds ? Valuation ? Base Metals ? Case Study ? Quebrada Blanca Hypogene Commodity Investment Cycle ? Macro-Economic Indicators ? LME Inventories ? watch the trend; rising inventories ? bad for prices, declining inventories good for prices ? OECD Leading Indicators ? PMIs ? Purchasing Manager Indices ? Industrial Production ? more important for metals consumption than GDP ? Housing Starts ? US, Europe ? Auto Sales ? All things China ? metal imports/exports; SHFE inventories; SRB stockpiling ? Seasonality ? it does play a role ? What is Chris Dutton (TDSI Quantitative Analyst) saying?

May 1, 2010

By L. A. Thompson, A. J. Linington

"Copper–cobalt extraction is a reagent-intensive process resulting in acid consumption greatly contributing towards production costs, which in the current market conditions curtail profitability. Nanofiltration (NF) membranes have become an attractive approach in the mining and minerals industry for product concentration and reagent recovery based on the ability of the membrane to separate monovalent ions from divalent ions. NF membranes can selectively separate acids from metals and salts allowing acid to be recycled as well as the concentration and purification of product streams. Membrane technology in the field of copper–cobalt processing focusses on the concentration of Cu2+ and Co2+ in the pregnant leach solution, recovery of acid from waste streams to neutralization, recovery of valuable metals from waste ponds and process water recovery. This paper aims to provide insight into the potential applications of NF membranes in copper–cobalt processing circuits as well as a brief overview of the effects of process conditions on membrane performance and process development. INTRODUCTION The copper–cobalt industry commonly uses inorganic acids, such as sulfuric acid, in large quantities for primary leaching of copper–cobalt oxide ores and releaching during product purification (Stuurman et al., 2014). This results in numerous acidic intermediate streams containing high metal concentrations and acidic waste streams with low metal concentrations. Acid consumption typically accounts for 10–15% of the operating costs of mines in the Democratic Republic of Congo (DRC) and Zambia (Acid Plant Database, 2015). Due to remote mine locations, poorly maintained roads and cross-border conflict, the cost of sulphuric acid can range between USD 300 and 400 per ton. The pivotal role of acid in the copper–cobalt extraction process has driven many mines to build sulphuric acid plants on site to ensure a reliable acid supply, however elemental sulphur still needs to be imported which faces similar logistical challenges and contributes towards operating costs."

Jan 1, 2015

By William R. Yernberg

SME’s Arizona Conference was held at the Doubletree Hotel at Reid Park in Tucson on Dec. 5and 6, 2004. The annual conference is organized by the Arizona Conference Board of Directors, which represents SME sections in Arizona and adjacent areas. The conference provides an opportunity for individuals and corporations associated with mining in the region to get together each year to discuss the status of the industry. The meeting featured a keynote address and more than30 technical papers. Two years ago, the U.S. copper industry was facing on a run for two years now,” and “both precious metal and base metal prices are going up.” The increases in metal prices were attributed to development in China and other Asian countries. “With a population of 1.6 billion, China has recently created 80 million jobs,” said Silver.

Jan 1, 2005

By John C. Machisak

STATISTICAL data on injuries and employment pertinent to metal mines and to their mills, and/or processing plants are presented in this Information Circular for the calendar year 1960. The information pertains to metal mines, as well as ore-dressing plants and primary nonferrous smelters, refineries and reduction plants, and their auxiliary works. These data are voluntarily submitted annually to the Bureau of Mines by the operators, and contribute greatly toward the promotion of safety in the mineral industries. The data presented are classified according to the principal mineral produced and include information on copper, iron, lead-zinc, gold-silver lode, gold placer, uranium-vanadium and miscellaneous metals. A breakdown of miscellaneous metals by commodities is shown in table 19, page 41. The data also relate to workers engaged in production, exploration, development, construction, and maintenance and repair work, as well as supervisory personnel and office-workers at the mine or plant site. Injury and employment data at metal mines and metallurgical plants in the United States for 1960 are shown under the following general sections: 1. General injury experience: Tables I-5-Data on injuries, injury-frequency and severity rates and related employment data, work location, and degree of injury.

Jan 1, 1963

By A. D. Engelbrecht

An investigation was undertaken to ascertain the suitability of four selected low grade, South African coals for gasification in a bubbling fluidized bed for production of synthesis gas and for the development of integrated gasification combined cycles (IGCC). This study consisted of the characterization of the coals, laboratory evaluation of intrinsic reactivity, and experimentation with a pilot-plant fluidized bed gasifier. Results of the characterization experiments show that the selected coals are high in ash, rich in inertinites, very dense (low porosity), with low caking indices and high ash fusion temperatures. Reactivity measurements with a thermogravimetric analyser (TGA), under reaction rate controlling conditions with carbon dioxide, showed that the reactivity of the coal chars decreases with increase in rank of the coal, as expressed by the vitrinite random reflectance and carbon content of the parent coals. The fixed carbon conversion achieved in the fluidized bed gasifier also correlates well with the rank parameter of the coal, with higher conversions being obtained with the lower rank coals. Thermal shattering and attrition of the coal particles produce significant amounts of fines, which correlate with the grindability indices, and no agglomeration (non-caking) was observed. It is concluded that fluidized bed gasifiers are able to utilize typical low grade, high ash South African coals for synthesis gas production and for inclusion in integrated gasification combined cycles for power generation.

Jan 1, 2010

By David G. Almond

"Economies of scale and the variable characteristics of many large ore deposits have resulted in grinding installations having large SAG mills fitted with variable speed drives. Problems associated with effective operation of this equipment has created the need for better operator knowledge of mill load behavior and the need for new instrumentation capable of providing accurate information about load movement and composition. This paper discusses two performance enhancing instruments available to address these needs.INTRODUCTIONThe economic demands of new mining projects has resulted in increased equipment sizes and this is particularly evident in milling where there are now many SAG mills operating in the range of 28’ – 40’ diameter with installed powers of 8 – 22 MW. These mills are designed to process very high capacities of ore daily2 and the variable characteristics of many of the deposits mined results in the need to vary the mill speed during processing to cater for the changes in ore hardness. Mill speed changes often result in operational problems associated with high-energy impacts striking the mill liners reducing energy efficiency as well as degrading the grinding media through breakage, accelerating liner wear and in extreme cases even breaking liners. These operational problems have given rise to the need to have instruments aimed at providing operators with accurate information in real time about the load composition and movement within SAG mills.The original concepts for operating SAG mills were derived from past experience of operation of conventional fixed speed ball mills. However, the relatively stable conditions that applies with fixed speed and constant ball charge in ball mills supports theoretical approaches to the grinding process based on energy calculations such as Bond’s Work Index concept. Later a set of parameters Si and Bij were used for describing load kinetics, but all of these methods neglect the details of load movement and how the energy is actually used inside of the mill. It is now commonly accepted as a basic rule that SAG mills grind by impact whilst ball mills grind by attrition and consequently SAG mills are designed and operated to generate a large amount of impacts by the cataracting load without paying sufficient attention to where these impacts are actually occurring. Many mills are operated on the basis that as long as the mill is consuming the expected power there is little attention given to the class of bodies using this energy and this often results in the inefficient use of energy."

Jan 1, 2005

By N. I. Aziz, I. Tague, P. Mackenzie-Wood

The recent mine disasters in Australian coal mines have initiated an introduction of Self-Contained Self-Rescuer (SCSR) as component in the development of new escape strategies for miners. These self-contained self-rescuers are closed circuit, demand sensitive breathing apparatus that make oxygen available to the wearer for a nominal period of time. Their operation is completely independent of the surrounding atmosphere. Once properly donned, the SCSR can assist a miner to escape from an area containing smoke, toxic gases or an oxygen deficient atmosphere. The duration of a typical SCSR is usually taken at the point of complete collapse of the breathing bag which is accompanied by an increase in breathing resistance and inhaled levels of carbon dioxide. Because the oxygen consumption (V02) and the heart rate are correlated, a prediction of V02 and consequently the duration of an SCSR can be made by monitoring the heart rate. Thirty-seven volunteers participated in field simulated escape trials at four underground coal mines. The results from the field trials suggested that oxygen consumption depends on the heart rate, the body weight and exercise rating of the miner. All the volunteers were asked to fill out the questionnaires to evaluate the performance of the units. The miners indicated that they could tolerate the inhaled temperature without any difficulty to breathing resistance. A complete statistical analysis of the field results is also presented.

Feb 24, 1997

The material presented in this paper describes experimental work to determine the effect of variations in suction nozzle design upon inlet flow conditions. Four entrance profile shapes were examined under controlled conditions of slurry flow and it was found that the straight ended nozzles had consistently higher entrance losses than the straight taper or the ellipse, and that the circular arc profile nozzles were the most efficient. Subordinate considerations were the measurement of the quantities and the forces involved.As the work progressed, three distinct phases in the pattern of flow were apparent and the static pressures in each were carefully examined. An inlet zone was found to be unstable in changing boundary conditions, a transition zone was largely independent of slurry density and in a zone of stability the pressures were found to be directly related to the characteristics of the flowing pulp. In this zone pressure measurements were reproducible within ± 2 per cent regardless of changing boundary conditions.The effect of varying the "1" parameter of nozzles with a part circular entrance profile was examined and it was found that flow conditions approaching the ideal were obtained when the radius of curvature was between 0·40 and 0·550.

Jan 1, 1966

By V. Eu. Anufriev

Despite of significant cost advantages and the positive expierence roof bolting is limited up to 15-20% of all workings at the Cuzbass mines. The low level of application of the technology is the result of specific mining and geological conditions and defects of organization and technical support. When analysing mining and geological conditions of development working maintenance and geomechanical aspects the necessity of changing of technological schemes of preparation and extraction of mine sections is obvious. The prospects of large-scaled transferring from frame support to roof bolting are connected with introduction the technology of support with the help of non- expanding bolt classes including bolts with mineral filler fixation. The design of bolters with mineral filler fixation is given here. The results of testing of bolt load characteristics in artificial holes and in situ are proved the technology efficient. For increasing of drilling works efficiency it is necessary to master the production of oilless compressor and heading machines with the manipulator. For bolt dimension forecast it is recommended to use the relations of measured parameters of "dome" to roof shifts. Effective monitoring of rock pressure in the junctions is connected with the use of support of conventional bolts together with bolts of deep installation with simultaneous supporting of face ends with special mechanical sets, which compensate face length change.

Jan 1, 1996

By T F. Guerin

Explorationn and mining have shown to cause significant impacts to the terrestrial and marine environment. Current mining and exploration techniques are outlined in the light of their potential to impact upon the environment, ie negligibly, negatively or positively. A profile of five Australian-based gold producers is presented. The development of protocols to specifically deal with the highly regulated and ever changing, mining and environmental legislation. demonstrates mining companies can successfully opcrationalise the concept of sustainable development.

Jan 1, 1992

By H Peiming, W Sakurai, Y Matsuhisa, H Shimazaki, Y Fukahori

Oxygen and carbon isotope mapping of hydrothermally altered wall rocks was applied to the blind ore prospecting of skarn Pb-Zn deposits in the Kamioka mining district, centralJapan, where the wall rocks consist of heterogeneous rock units. The results (d18OSMOW of -1.1 to +17.3ë and d13CPDB of -5.0 to +4.8ë for limestones, and d18OSMOW of -0.8 to +12.5ë for silicate rocks) show isotope zonations of the wall rocks with depletions in heavy isotopes (18O and 13C) toward the centre of mineralization. The isotope zonations likely formed by interaction of migrating thermal waters with the wall rocks during the mineralisation. The heavy-isotope depleted zone, which indicates higher temperature or higher water-to-rock ratio of the system, occurs in the footwall of a fault, indicating that the fault played the role of main conduit of the ore-forming fluids. A heavy-isotope depleted zone was also found in an area, where significant mineralisation had yet to be identified. Recent drilling in this area has intercepted a zone with a grade of 16.0% Zn, 0.8% Pb, and 35g Ag per metric tonne at a depth of about 360 m.

Jan 1, 1995

By Franz-Werner Gerressen

"The use of soil improvement to utilize areas, which are not suitable for foundation purpose, has a long tradition. Due to the increasing demand of foundation works in areas of unsuitable soils, the improvement of the existing soils becomes even more important in the future.Various applications and systems for various demands exist around the world. Either it is a “simple” improvement for settlement reduction or a more important aim as liquefaction mitigation. However, each system has its advantages, limits and needs.Furthermore to the soil improvement, using various tools, soil mixing can also be used for applications like cut off and/or retaining wall.The paper will describe some basics of various techniques and different applications of the systems all over the world where the systems provided solutions for different purposes, e.g. simple foundation or liquefaction mitigation.It will describe also the main equipment which will be needed to execute these works under the various conditionsINTRODUCTIONSoil mixing is a methodology where the soil is improved by mixing it with cement, lime or other binders in situ by using a mixing tool. This methodology can be used either as wet mixing or as dry mixing. In the more frequently used wet mixing process, usually a mixture of binder and water, maybe with additives, is injected and mixed with the soil. Depending on the type of soil and binder, by the end of the mixing process, a mortar like mixture is created which hardens during the hydration process. In the dry mixing process, the binder is directly mixed with the soil and reacts directly with the existing soil and water.Mixing tools show several versions, so that they are mixing around either a vertical or horizontal axis, mixing in a trench and maybe are jet assisted. Figure 1 shows a classification done by Bruce 2010. Depending on the technique, improvement depth of up to 80 m can be achieved."

Jan 1, 2017

By John Nunes, Frank R. Larson

Temperature-dependent functions of various ten-sile flour stress and fracture parameters were investigated on iron and low composition alloys of Fe-C, Fe-Cr, Fe-Mn, and Fe-Ni. Data were obtained over a range of test temperatures from 200" to -196"C at an initial strain rate of 0.01 min". It was found that the strain-hardening exponent, n, for the Fe-Ni alloys increased significantly at very low testing temperatures with increased alloy addition. Also, the stress and strain at fracture followed a predictable transitional type of behavior. The flour stress-temperature dependence was evaluated employing the relation: M where it is shown that composition can strongly influence the constant M. An empirical formula describing this effect is as follows: M = MI (equivalent at. pct Ni)-'" Some preliminay, tests were run on several commercial steels to test the generality of this relationship. One of the phenomenological explanations of the ductile-to-brittle transition encountered in bcc metals is based upon the difference in the temperature dependence of the flow and fracture stresses.' It states simply that the fracture stress is relatively insensitive to temperature and that the yield or flow stress rises rapidly with decreasing temperature so that, when the flow stress reaches the fracture stress, brittle fracture occurs without appreciable plastic deformation. This behavior is illustrated schematically in Fig. 1 where the ductile-to-brittle transition is shown to occur at two possible temperatures. The lowest temperature, TB, represents essentially completely brittle behavior while the higher temperature, TN, represents "notch" brittle behavior. Support for this theory is obtained when it is observed that fcc metals, which do not commonly have a ductile-to-brittle transition, also do not commonly exhibit any strong temperature de- pendence of the yield stress. This relationship of yield or flow stress behavior with the ductile-to-brittle transition has been generally observed for most metals representative of these two crystallo-graphic structures. One exception to this generalization appears in the case of tantalum where no apparent ductile-to-brittle transition has been observed. However, this may simply be an indication that this type of behavior is not directly related to the flow stress and that some other mechanism such as twinning must also be operative. A comparison of the typical temperature dependence of the yield stress of some representative metals is shown in Fig. 2. In the study of the temperature dependence of the strength of metallic materials, considerable ef-

Jan 1, 1963