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By Robert R. French

Commercial grade gypsum beds up to 16 feet thick is present in southwestern Indiana. The major deposits are found at a depth of 350 feet to more than 500 feet below the surface. The ore body averages about 75 to 95 percent gypsum. Two companies are currently exploiting a deposit which underlies an area of several square miles near Shoals, in Martin County. Another deposit has been located in southwestern Owen County but has not been developed. The Indiana Geological Survey is currently drilling in Greene County and is considering further exploratory work in Perry end Dubois Counties.

Jan 1, 1965

By I. S. Parrish

As noted by McKinstry (1948), "How to deal with erratic high samples is one of the knottiest problems in ore estimation." He described a variety of approaches and methods to alleviate the problem through the averaging and weighing of assay data and by "cutting" or "clipping" of the erratic assays. Bird (1991) elaborated on ways of dealing with the nugget effect (erratics). He listed several procedures for cutting. Bird's list has been reproduced and/or added to by several authors including Vallee (1992) and Stone and Dunn (1993). Missing from each of these otherwise excellent reviews is a definition, description or guideline to recognition of an "erratic," or just where or when cutting is warranted or justified.

Jan 1, 1997

By Anita Wu

"GENERAL BACKGROUND/CONTEXT The £300 million Bond Street Station Upgrade project will provide essential congestion relief and step-free access to an important interchange and destination station in the heart of the London Underground network. In 2010 London Underground (LU) let a design & build contract to Costain Laing O’Rourke (CoLOR), with the works to be completed in early 2017. CoLOR’s lead designer is Halcrow-Atkins JV (HAT). The station upgrade works comprise the following principal elements: •,A new satellite ticket hall on the North side of Oxford Street •,Two additional escalators and stairs providing congestion relief to the Jubilee line platforms •,Four lift shafts to provide step-free access between the different levels of the station •,Additional stairs to Central line platform level •,Tunnelled connection to the Crossrail station immediately to the south •,Connecting passageways, including ten connections to existing station tunnels. To achieve this, an existing property at 354-358 Oxford Street has been purchased and demolished, and the basement deepened to make provision for the new ticket hall. From this basement two circular shafts have been sunk, providing construction access for the tunnelled passages and lift and escalator shafts. The tunneling is principally in the London Clay stratum, which is widely recognized as a favorable tunneling medium, although the deepest parts of the works extend into the Lambeth Group strata which consist principally of stiff clays at this level but also contain water-bearing sands. The majority of tunneling has been carried out using mechanical excavation and sprayed concrete linings but other techniques have been used in areas where SCL is not practicable.A key challenge for design and construction of the works has been spatial constraint, in particular due to: •,The existing underground station layout •,The Limits of Deviation for the works •,The small construction site at 354-358 Oxford Street •,Overlaying Third Party assets including Listed buildings, sewers and water mains."

Jan 1, 2016

By James Withers, Dongbo An, Jinhong Zhang

A micro-scale investigation was carried out by applying an atomic force microscope (AFM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to study in situ the adsorption of three different collectors — oleic acid, octanohydroxamic acid (HA) and salicylhydroxamic acid (SHA) — on bastnaesite in aqueous solutions. The results show that all three collectors adsorb on bastnaesite. The hydroxamic acid collectors — HA and SHA — adsorb on bastnaesite mainly in the form of insoluble metal hydroxamate. Their specific adsorption mechanism indicates that high selectivity will be achieved with a hydroxamic acid collector for the flotation of bastnaesite.

By K. V. Raj

"The development and advancement of computational fluid dynamics (CFD) has made it possible to better understand pollutant flow and distribution in deep open pit mines. Open pits located at higher latitudes, especially in the Arctic and sub-Arctic, face a unique problem due to atmospheric temperature inversion, which is prevalent during much of the winter. A three-dimensional CFD model of an actual open pit mine in the Arctic was developed to analyze the problem of pollutant growth during inversion, and mitigation of the pollutants through improved ventilation schemes. Due to the availability of mine-specific data, such as contaminant concentrations and coordinates of sampling locations, the actual 2013 pit geometry was used for model validation Concentrations predicted by the selected realizable ?-e turbulent model are compared to measured pollutant concentrations at the open pit. Pollutant concentrations at selected locations showed differences, but remained within the same order of magnitude in most cases. INTRODUCTION Computational fluid dynamics (CFD) has emerged as a useful tool for ventilation modeling in underground mines (Edwards and Hwang 1999, Purushotham and Bandopadhyay 2009, Wala et al. 1998, Xu et al. 2011). Application of CFD in open pit mines has been limited, however, since most open pit mines located at lower latitudes do not encounter considerable ventilation problems. Open pits located at higher latitudes, especially the Arctic and sub-Arctic, face a unique problem due to atmospheric temperature inversion, which is prevalent during winter. A number of Russian researchers have tried to understand the air inversion and resulting pollutant transport problem by modeling air flow phenomena in open pit mines (Baklanov and Burman 1996, Baklanov 1984, Baklanov 1995, Belousov 1985, 1989, 1995). Much of their work, however, was based on numerical models and methods of finite difference. Baklanov (2000) applied a modified ?-e and a ?-l CFD model to air flow phenomena on various terrains. More recently, Choudhury (2011) used the COMSOL CFD package for modeling pollutant transport for an idealized open pit mine. Collingwood et al. (2012a, 2012b) used a two-dimensional model for fluid flow and contaminant transport at an Arctic open pit mine. The authors have also previously presented work on CFD modeling of an actual open pit mine at high latitude (Bandopadhyay et al. 2014, Raj et al. 2015a). However, the CFD work done by the above-cited researchers lacked model validation with field-measured data. Validation of a developed model is important in assessing the quality and accuracy of the predicted results. In general, experiments are done numerous times in controlled environments to assess the validity of collected data. There are two types of assessments used in CFD simulations: (1) verification and (2) validation. Model verification is checking the accuracy of the computer codes during the implementation phase of a real-world problem, within the specific limits of accuracy (Oberkampf and Trucano 2002). Since, the pollution transport model presented in this paper used the commercial ANSYS-FLUENT CFD package, verification is not needed as the program has been tested widely, and verified numerous times."

Jan 1, 2016

By J. J. Knoerzer

The scheduled replacement of Inland's A & B coke batteries in Plant No.3 posed some serious problems in terms of pollution control and strained sources for medium volatile coal for a conventional blend. The state-of-the-art of air pollution control during the charging step in the conventional slot-type coke oven has been less than satisfactory. In addition, the work done at the Illinois Geological Survey showed that by preheating the coal blend prior to charging a greater percentage of Illinois coal could be used to produce a high quality metallurgical coke. To assist The Management in the- decision on A & B replacement, Inland Steel conducted a full-scale test program on coal preheating and pipeline charging utilizing the Coaltek system installed on No. 2 battery of the Semet-Solvay Division of Allied Chemical Corporation. The basic objectives of the test program at Semet-Solvay were as follows: 1. Determine the feasibility of producing high grade metallurgical coke from preheated blends containing more than 60% Illinois No. 6 coal. 2. Confirm the performance characteristics in one of the Inland blast furnaces of the coke produced with 75% Illinois coal in the blend. 3. Verify several claims by Coaltek such as: a) Pipelining the hot coal presents no difficulties while essentially eliminates the air pollution problems associated with the conventional charging system. b) Preheating of the coal blend permits the use of higher percentages of high volatile, marginally coking coals (such as Illinois No. 6) in the blend as compared to wet charging.

Jan 1, 1973

By Alfred W. Eustes III

The first of a series on the evaluation of rock cutting tools, this paper discusses the results of full-scale laboratory drilling tests that compare the performances of several polycrystalline diamond cutter (PDC) coring bits. The tests were performed in welded tuff as part of a site characterization program. Number of cutters, size of cutters, air course design, and other parameters were evaluated as they affect penetration rate, but this paper focuses mainly on the relationships of torque vs. thrust (weight-on-bit), specific energy vs. penetration rate, and thrust vs. penetration rate. These relationships change in diagnostic ways according to bit type, bit condition, and type of welded tuff.

Jan 1, 1998

By Per-Martin Sandgren

LKAB's ores have specific mineralogical properties that make them especially suitable for the production of super-grade concentrates. Conditions are particularly good for this purpose at Malmberget, where a concentrate for high-purity sponge iron production has been produced for many years. Until 1978 the approximate assay was 71.2 % Fe and 0.45 % SiO2. Since then the assays have been improved by process modifications to approximately 71.5 % Fe and 0.20 % SiO2. Scope exists for still further improvement. In recent years the production of fractioned concentrates has been started. The material lies within the size range 74-125 µm and the approximate chemical analysis is 71.6 % Fe and 0.30 % SiO2. Other special products are under discussion. The Malmberget ores are also suitable for the production of high-purity direct reduction pellets with a SiO2 content below 1 %.

Jan 1, 1981

By J. R. Koehler

Yield pillar-based gate road designs oftentimes fail to provide mine operators with adequate ground control because of the unknowing misemployment of "critically" sized pillars. A "critical" pillar is one that is too large to either yield nonviolently or yield before the roof and floor sustain permanent damage, but is too small to support full abutment loads. To demonstrate the critical pillar concept, a field study of a tapering gate road was conducted by the U.S. Bureau of Mines at the Sunnyside Coal Mines, Sunnyside, UT. Extreme pillar stresses and associated coal bumps characterize the response to first panel mining of a 16.8-m wide critical design. Significantly lower pillar stresses, early yielding of the pillar and adjacent panel rib, and an absence of coal bumps suggest that a narrower 12.2-m-wide design more closely approaches proper yield pillar dimensions. Probehole drilling of several 1 O.6-m-wide pillars revealed low stress levels and substantial pillar and panel rib yielding prior to abutment onset, indicating a properly functioning yield pillar design.

Jan 1, 1995

By W. A. McKinney

The U.S. Bureau of Mines, Kennecott Copper Corp., and New Mexico Institute of Mining and Technology are cooperating on a research project to improve extraction of copper from previously leached waste dumps that are in part compacted and impervious to leach solutions. The field work is being done at the "J" leach dump, Chino Mines Division, Kennecott Copper Corp., Santa Rita, N. Mex. The laboratory percolation leaching tests were made at the U.S. Bureau of Mines Salt Lake City Metallurgy Research Center on drill core samples from the "J" dump to determine how much copper might be leached if permeability could be restored by explosive heaving or other means. The core samples from nine drill holes on "J" dump contained from 0.06 to 0.14 percent copper. Copper extractions ranging from 15 to 3 percent were obtained in 75 days by percolation leaching of minus-1-inch material with dilute sulfuric acid. The tests results indicate that about 2'7 percent of the copper remaining in the "J" dump could be extracted under ideal leaching conditions.

Jan 1, 1970

By T. McWaters

In 1911, Miami Copper Co. began a block caving operation at its Miami, AZ property. A gravity mill was used to separate copper minerals from the Pinal Schist host rock. Until 1932, the mill tailings were deposited by the upstream method using perimeter launders and spigot valves in six canyons adjacent to the mill. In 1928, the larger and more distant Solitude tailing pile was developed. By 1932, it was receiving all tailings. In 1925, Miami Copper converted the gravity mill to flotation with sulfide copper recoveries. From 1934 to 1943, Miami, Copper ran a leach-precipitate float (LPF) circuit on mined ore and, in 1943, began sulfuric acid in-place leaching of a portion of the caved area formed by block caving. The pregnant solutions were collected underground and pumped to the LPF precipitating drums to harvest copper. In 1954, the company started mining low-grade ore. This led to the running an old LPF plant on select mill tailings from April 1957 to March 1959. In 1959, block-cave mining ceased. Solution mining became the only source of production using a launder precipitation plant. In the mid-1960s, Miami Copper merged with the Tennessee Corp. In the latter part of the decade, Cities Service Co. bought the combined properties. In 1976, Cities Service commissioned a 15-t/d (16.5-stpd) solvent extraction electrowinning(SX-EW) facility at its Miami copper property to replace the precipitation plant. In 1982, Occidental Petroleum Co. bought Cities Service. In 1983, the Miami operations were sold to Newmont Mining Corp. and set up as a subsidiary company, Pinto Valley Copper Corp. Finally, in 1987, Newmont Mining spun off a combined Pinto Valley and San Manuel unit as Magma Copper Co.

Jan 1, 1990

The Mining Foundation of the Southwest will hold its 15th annual American Mining Hall of Fame Awards banquet on Saturday, Dec. 6,1997 in Tucson, AZ, preceeding the Arizona Conference of SME. The Mining Foundation's Hall of Fame, located in Tucson, recognizes outstanding contributions to the mining industry by individuals and industry partners. A permanent display of honoree vitae is located at the Arizona Historical Society at 949 E. Second St. in Tucson. Each year, one living award recipient and up to two honorees from mining history are chosen by the Hall of Fame committee and the board of governors of the Mining Foundation. In 1989, the Mining Foundation also initiated a Medal of Merit to recognize outstanding individual technical and professional contributions to the mineral industry. And in 1995, an award was instituted to recognize contributions made by companies and organizations in partnership with the mining industry. This year's inductee is James R. Moffett, chairman and chief executive officer of Freeport-McMoRan Copper and Gold Inc. He will be present as guest of honor and featured speaker. The Hall of Fame will induct John V. Dorr, metallurgist and chemical engineer. Also inducted will be Frederick L. Ransome, a geologist. Medals of Merit will be awarded to Hugo T. Dummett, senior vice president, Exploration BHP Minerals, and Spencer R. Titley, professor in the Department of Geosciences at the University of Arizona. An Industry Partnership Award will be presented to the Colorado School of Mines for its continued support to the mining industry through education and research. The banquet will be held at the The Westin LaPaloma in Tucson beginning with cocktails at 6:30 p.m. Tickets are available from Clare A. Roscoe, manager, Mining Foundation of the Southwest, telephone 520-577-7519, fax 520-577-7073.

Jan 1, 1997

By M. W. Harmer

Laboratory test work, pilot plant testing and plant experience with wet, fine mesh screens is discussed. High frequency, low amplitude, fine mesh, wet screens were installed on the 6th cleaner concentrate stream. These screens produce a 60% oversize recovery split of the molybdenite concentrate that is of leached equivalent quality. The undersize stream is leached with 'hot ferric chloride to remove Pb and Cu contaminates before roasting or shipment to sulfide customers. This plant modification is a good example of using existing technology in an unconventional flow sheet to yield significant cost savings.

Jan 1, 1990

By M. Visnjic

Open Pit Mine Production scheduling under commodity price uncertainty suffers from an exponentially increasing problem size as simulations and real options flexibility are used to generate and evaluate multiple production schedules. Robustness evaluation techniques attempt to evaluate a production schedule that is generated on a single set of economic parameters against several varying prices and sources of uncertainty. This approach is invalid as the corresponding optimal LOM mine plan will change for each set of evaluation parameters. Using commodity market futures and treasury bonds as production schedule economic input parameters provides fully price and time-value-of-money risked scheduling parameters that maintain a deterministic problem size. This paper will provide comparative analysis of project NPV’s coming from traditional price uncertainty evaluation based on a single fixed LOM mine plan using varying prices versus evaluation based on varying LOM plans that are both generated and evaluated using varying prices. When cross evaluating constant price mine plans against simulations, the upside potential and downside risk of a project are significantly misrepresented. INTRODUCTION The life of mine (LOM) production scheduling problem seeks to answer the question of from where and when to extract a given block within the ultimate pit limit as well as where and when to process it. Solving this problem takes into account the constraints of extracting any particular block while seeking to maximize the net present value (NPV) of the mineral asset as a whole. A direct driver of the value of a block, and there for the entire asset, is the market price of the commodity in question. Complications arise when an optimal production schedule is attempted to be solved under price uncertainty. Many solution methodologies have been proposed in an attempt to optimize under this criterion, yet there are three salient aspects that are overlooked during this process. They are: • Generating a single production schedule and evaluating it against many simulated price paths. • Failing to understand the mechanism describing particular commodity price behavior • Inappropriate risk adjustment In an effort to address these aspects of production scheduling under commodity price uncertainty, we propose a methodology to define the economic parameters as input that is applicable to most if not all production scheduling approaches. This methodology will not only simplify the production scheduling process in terms of establishing block value but utilizes the risk adjustment of real options valuation to avoid the arbitrary blanket risk adjustment of traditional discounted cash flow valuation. Our findings conclude that attempting to optimize around individual price paths is futile and using a market risk adjusted single price forecast provides a justified economic basis for production scheduling while maintaining the same problem size as a deterministic production scheduling problem.

Jan 1, 2019

By Michael J. Beus

This paper describes research conducted under the BuMines's Advancing Metal and Nonmetal Mining Technology Program, a major element being the application of new and improved technology to shaft design in deep underground vein-type mines. Two basic design parameters considered in shaft planning are configuration (shape) and ground support. The most common shapes are circular and rectangular. Ground support systems include concrete, timber sets, steel sets, rock bolts, and steel liners. The inherent advantages and/or disadvantages of various shaft designs such as ventilation and fire resistance, flexibility and ground support characteristics are well known. Circular concrete-lined shafts have minimal resistance to air flora and are virtually fireproof, an important consideration in deep hot mines. However, concrete does not yield significantly, and failure conditions and misalignment cannot be easily repaired. Timber-supported rectangular shafts predominate in the Coons d'Alene Mining District with its highly stressed and frequently heavy ground. The sets can be relieved and reblocked when out of alignment. However, the constant maintenance and repair requirements result in exposure to an inherently dangerous working environment combined with excessive operating costs. Obviously a dilemma exists--a circular, concrete-lined opening has many desirable features, provided it is strong enough to withstand the stresses involved. Rectangular, timber supported shafts have proven adequate in the Coeur d'Alenes; however, the implication of increased maintenance and repair requirements on ever-deepening shafts in this district and other similar areas will be an important design consideration in the future. This paper, then, presents shaft-configuration and ground-support guidelines to help remove some of the uncertainty concerning the stresses to be encountered in typical deep vein mining areas.

Jan 1, 1976

By A. E. Strakele, M. W. Springett, S. N. Watowich, W. F. Matlack, E. Yeomans, S. L. Manske, B. Yeomans

The Mesquite gold deposit is a large, low-grade "disseminated" ore body located in the Chocolate Mountains 65 km (40 miles) northeast of El Centro, CA. The deposit is tabular in geometry with a gentle southwest dip, concordant to a sequence of quartzofeldspathic to mafic gneisses. The host gneisses are amphibolite grade and intruded by synkinematic leucogranite and pegmatite. Reset potassium-argon (K-Ar) dates of 32 to 38 m.y. on mineral separates from gneiss in the ore body are suspected to reflect the age of mineralization. The hypo gene mineralization was introduced with siliceous breccias and -quartz veinlets and consisted of argentiferous native gold associated with minor pyrite and other base metal sulfides. Fluid inclusion study of gangue quartz indicates that the hydrothermal system contained a 225°C (437°F) boiling, 1 wt % NaCl equivalent solution with a small amount of CO2-A high degree of post-mineral faulting and fracture has resulted in deep oxidation and has obscured the original geometry and hypo gene mineralization of the ore body.

Jan 1, 1987

By Cem Şensöğüt, Özer Ören, Yaşar Kasap

The mining sector is one of the leading sectors where work accidents are most intense because of the constant change of work environment and heavy working conditions. The losses and the halt of production after the accident negatively affect productivity and production efficiency. It has been found that there are very few studies on the use of Data Envelopment Analysis (DEA), which is one of the nonparametric efficiency analysis methods, in the evaluation of mining sector occupational accidents. According to parametric activity measurement methods, it has been tried to show that the DEA can also offer the opportunity to interpret work accidents by taking advantage of its advantages. Due to the application of open-pit mining methods along with underground working techniques which increase the risk factors with respect to accidents at work that occurred between 2012 and 2018 of Western Lignite Corporation (WLC) were tried to be analyzed in the present work. As a result of the analytical work using Data Envelopment Analysis (DEA) for the years 2014, 2015, 2016, 2017, and 2018, inefficiency has been determined in both underground and surface operations. According to the results obtained, it was determined that WLC could not produce enough production in both the underground and surface coal mining operation, despite the accidents that occurred, while it had the opportunity to produce more. In addition, it was found that the increase in accidents occurred more than the increase in the amount of production during the years studied.

Jul 4, 2021

By S. Garcia

The Minera Yanacocha operation presents various operating challenges, due to the complex structure of several heaps interconnected with ponds and gold recovery plants. A comprehensive process model has been developed in order to better understand the effects of certain operating parameters on issues such as water usage and inventory. An integral component of the water/mass balance of the process is a model of each heap that describes the flow and chemical behavior based on the individual characteristics of the heap. A computational fluid dynamic (CFD) software framework is used to model the individual heaps. The structure, calibration and validation of the model are described. Several examples demonstrating application of the process heap model are presented for the La Quinua heap. The effects of loss of solution flow to the heap (i.e., pump failure), increased cyanide levels in applied solutions and higher copper head grades on the process operation and balance are investigated with model simulations and compared to the baseline operating conditions. An example of estimating gold production and inventory based on projected heap loading plans is provided.

Jan 1, 2010

By C. Sun

The Leeville underground mine has been in operation since 2006 and currently produces 2,903 t (3,200 st) of ore per day, with an average gold grade of 0.4 opt. The mine’s horizontal extent is large, 762 by 152 m (2,500 by 500 ft), while its vertical extent is 6 to 61 m (20 to 200 ft). A high density of joints occurs within the host rock. Based on rock mass rating and field observation, the ground conditions at Leeville can be characterized as poor to very poor. As such, heavy ground support is required for its mining operation. Ore zones with a height in excess of 10 m (35 ft) are considered for longhole stoping. A typical stope measures 6 m (20 ft) wide, 30 to 55 m (100 to 180 ft) long, depending on the ground conditions, and 10 to 30 m (35 to 100 ft) high, depending the thickness of the ore body, yielding 9,100 to 18,000 t (10,000 to 20,000 st) when completed. Narrow ore zones, less than 10 m (35 ft), are mined using cut and fill. Drifts at the Leeville Mine are 4.6 m (15 ft) wide by 4.6 m (15 ft) high. Because of poor ground conditions at this mine, the establishment of a ground control monitoring system is key to operating both safely and successfully. This monitoring system is composed of comprehensive instrument design and installation. Instruments include multi-point borehole extensometers (MPBX) and “stretch measurement to assess reinforcement tension” (SMART) cables. The monitoring system covers the mining zones and infrastructure openings. After about two years’ application and measurement, useful data has been collected and continues to be collected; this information will be used to design future stopes and infrastructure. The system makes engineering and operation teams able to do their job with more confidence and efficiency.

Jan 1, 2009

By M. J. Zdunczyk

The final 1995 figures on industrial sand and gravel have not yet been compiled by the US Geological Survey (USGS). There is usually about a nine-month lag time in receiving and compiling this information. However, USGS estimates that domestic production of industrial sand and gravel will increase about 4% to 28.2 Mt(31 million st). The average unit price is expected to increase as well. The top five producers during 1995 were Unimin, US Silica, Fairmount Minerals, Oglebay Norton and Morie Co. Glass manufacturing for containers, automobiles and buildings was mixed during 1995. Containers, the largest consumer of silica sand, remained steady, with regional increases. However, silica use in glass containers face increased competition from plastic and recycled glass (cullet). It was reported that the Pepsi Cola announced plans to replace glass containers with plastic during 1996.

Jan 1, 1996