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By H. Maleki

This paper recognizes the 100th year of research accomplishments by the mining industry resulting from close cooperation among mining companies, geotechnical consultants and researchers from the former United States Bureau of Mines in stability assessments and development of improved and productive mine designs. The paper provides an overview of dramatic developments in geotechnical instrumentation, and its applications in the U.S. and around the world for enhancing the understanding of ground response to mining-induced changes in stress, resulting in improvements in ground control technologies.

Jan 1, 2010

By Ray E. Williamson

One of the prime objectives of the mine industry is to develop a low cost way to clean up what has been called "The Rape Of Mother Nature". The project falls under the broad umbrella of reclamation, which is now considered an essential part of the mining cycle. As such, it is being given full consideration in the initial planning of all surface operations. In most areas, if a proposed mining system does not lend itself to proper reclamation, it is not an acceptable system. By combining mining and reclamation plans, a producer not only can minimize reclamation costs, but can also restore the land to usefulness and insure continuing profits after a deposit is depleted. As long as fifteen years ago, many of the larger mining companies were already deeply involved in this extra cost work. Even then the involved companies were projecting a great need for a bigger bulldozer, Bigger than anything commercially available. At that time, the D9 tractor weighed about 60,000# bare weight.

Jan 1, 1975

By A. A. Terchick

In 1970 U. S. Steel acquired the physical assets of mine, mine property, and preparation plant of the Crystal Block Coal Company near Thacker, Mingo County, West Virginia. The facility, identified as U. S. Steel Mine No. 20, is administered and operated as a production unit of U. S. Steel Gary District, Gary, West Virginia. Mining operations of the No. 20 mine are conducted in the high-volatile Alma seam. The preparation plant, which originally had a capacity of about 150 tons per hour (tph) of raw-coal feed, had process circuitry consisting of a Daniels heavy-media vessel for cleaning the plus-1/4-inch raw coal, a McNally-Pittsburg feldspar jig for cleaning the 1/4 inch by 28 mesh, and Daniels flotation cells for treating the 28 mesh by 0. No water-classification system existed. Refuse tailings from the plant were pumped to several surface lagoons which were decanted to the stream. The settled solids were removed and trucked to the coarse-refuse disposal area. Water make-up requirements were supplied by a small mine-water surface reservoir and augmented with stream water. Expansion of production from the property required an increase in preparation-plant raw-coal-feed rate capacity from

Jan 1, 1974

By D. W. Alexander

In 1993, CONSOL began investigating new methods of permanently filling coal mine shafts, which after ventilation is stopped, may contain a potentially hazardous atmosphere. Fill materials such as fly ash/cement can be pumped, are non-combustible and non-incendiary but tend to flow into the mine entries. A non-flowable mixture has been developed that minimizes the volume of fill used. The paper presents our recent shaft filling experience including fly ash material properties, mix designs, field problems, placement success, and gas testing techniques.

Jan 1, 1996

By Hamid Maleki

Mine seismicity is influenced by the mechanical properties of both near-seam rocks and overburden and the prudent selection of mining methods and mine layout designs. Using finite-difference modeling, experience in many U.S. mines and measurements of the pressure arch width, the author has reviewed the engineering design factors that control seismicity in room-and-pillar retreat operations for stiff stratigraphic conditions in deep western U.S. mines. By back analyzing the overburden response in now understood to have been inadequately designed historic room-and-pillar mine, the overburden collapse mechanism is addressed as well as the need for improvements in designs including panel and barrier pillar widths, and sequence of retreat.

Jan 1, 2009

By Miles L. Silberman

Three major suites of igneous rocks were erupted in the Great Basin in middle and late Cenozoic time. The first, most likely, resulted from sub- duction of a Pacific plate (Farallon plate) beneath the North American plate, resulting in eruption of andesitic rocks in the northern Great Basin between 42 and 43 m.y. ago. Between 34 and 17 m.y. ago, igneous activity migrated to the southwest, largely as eruption of volumincus rhyolite-quartz latite ash-flow sheets, ending about 17 a.y. ago with the onset of crustal extension and north-south-trending Basin and Range (rift) faulting. The second volcanic suite erupted between 17 and 8 m.y. ago in the northern Great Basin; is mostly basaltic or bimodal basalt-rhyolite. The third volcanic suite consists of andesitic and rhyolitic lavas and some basalt erupted between about 22 to 6 m.y. ago in the western Great Basin along the northwest-trending Walker Lane fault zone. Hydrothermal ore deposits are associated with all suites of igneous rocks, but the largest production has come from mines associated with andesitic rocks of the third (western Great Basin) suite. The oldest (34 to 42 m.y.) andesitic rocks (first suite) of the northern Great Basin have produced some large deposits; slightly younger silicic rocks of this suite are mostly barren. Many small ore deposits are associated with the 17- to 8-m.y.-old basalts (second suite) of northern Nevada.

Jan 1, 1976

By C. A. Young

Cyanide is a toxic species that is found predominantly in industrial effluents generated by metallurgical operations. Cyanide's strong affinity for metals makes it favorable as an agent for metal finishing and treatment and as a lixivant for metal leaching, particularly gold. These technologies are environmentally sound but require safeguards to prevent accidental spills. Various methods of cyanide remediation by separation and oxidation, including photolytic advanced-oxidation processes, are therefore reviewed. Reaction mechanisms are presented throughout the paper. The methods are compared in regards to their effectiveness in treating various cyanide species: free cyanide, thiocyanate, weak-acid dissociables, and strong-acid dissociables.

Jan 1, 1996

By C. I. Basilio

Pearson's hard and soft acid and base (HSAB) principle may be applied to flotation systems. The HSAB principle states that hard acids prefer to bond with hard bases and soft acids prefer to bond with soft bases. By determining the Drago E and C parameters for the different components of a flotation system, the HSAB principle could be used to explain the selectivity of some collectors such as thionocarbamates against some minerals. Determination of these parameters is done by utilizing Drago's theory and flow micro-calorimetry.

Jan 1, 1991

By H. W. Gao

During the last decade, the feasibility of applying the in situ leaching technology to the recovery of copper from deeply buried deposits containing chalcopyrite has received much attention.(1-4) The major incentive for using this technology is that under certain circumstances, copper in deep underground deposits, which cannot be mined economically by conventional means, can be recovered economically. Basically, this technology involves rubblization of the deeply buried copper ore body followed by in-place leaching of the rubblized copper ores. Rubblization of the ore can be achieved by some suitable method such as the use of block caving mining. The rubblized chimney is then filled with water until the original water level is reached. Leaching occurs when the eater saturated with oxygen is introduced into the chimney- and flows through the fractured rock masses and within pores of rocks. As the dissolved oxygen oxidizes the primary sulfides, heat is generated. Because of low conductivity of the surrounding rocks, the generated heat is able to raise the temperature of the chimney. The increase in the temperature of the chimney and the relatively high content of dissolved oxygen in the leach solution under high hydrostatic pressure will result in an enhanced dissolution of the primary sulfide minerals. To ensure a successful application of the in situ leaching technology, a complete understanding of the effects of the ore particle size distribution, ore grade mineralogy, temperature, pressure, lixiviant concentration, pH, etc. on the rate of copper recovery is necessary so that copper can be recovered efficiently and the amount of copper extracted can be predicted. These can be achieved through mathematical modeling of the in situ leaching process and conducting laboratory tests. In this paper we will present a mathematical model that simulates the in situ leaching process as depicted in Figure 1. To model this process properly, not only the 'kinetic and thermodynamic aspects of leaching chemistry must be known, but the effects of heat generation, the physical aspect of fluid flow and other related multicomponent transport phenomena must be considered. Furthermore, since most factors involved in the leaching process change with time, a leaching system must be described using unsteady state equations.

Jan 1, 1981

By R. E. Doerr

The successful technical demonstration of coarse coal slurry transportation at Consolidation Coal Company's Loveridge Mine in West Virginia suggests that it is now appropriate to seriously consider this technology in other applications, especially the transport of ' coal in surface mining. Early examination indicates that coarse coal slurry transport may be highly competitive with existing haulage systems, depending on a number of factors. These factors are not yet completely defined, but certainly will include production rates, coal physical and chemical properties, terrain, soil conditions, climate, water availability and quality, availability of skilled labor and other economic considerations impacting the existing haulage systems.

Jan 1, 1983

By R. M. Quinlan

The coal industry in the United States has undergone significant economic changes during the past six years. The price of coal remained relatively constant from 1950 to 1969 (See Figures 1 and 2). Steam coal prices tripled and metallurgical coal prices doubled from 1969 to 1974. This price structure has created a new economic environment for coal preparation. Contributing factors to these price trends include: ? Coal Mine Health and Safety Act of 1969 ? Mid-East oil embargo of 1973 ? United Mine Workers of America contract agreements ? Productivity decrease (tons per man-day basis) ? Environmental Protection Agency regulations The increased value of coal justifies additional capital investment in cleaning facilities to optimize yield. Current trends include recovery of existing slurry ponds and recleaning of refuse. Coal preparation plant product yield and quality must be evaluated in terms of the amount of capital expended and cost of operation. Therefore, it is advantageous to optimize the plant product based on clean coal selling price and rate of return on investment.

Jan 1, 1976

By S. R. Hutchins

Several refractory sulfide and carbonaceous gold ores were examined to determine whether microbial pretreatment could be used to enhance gold recovery. Test samples were biologically leached using unique, thermophilic microorganisms to solubilize iron sulfide minerals. Gold recovery from sulfide ores and concentrates was enhanced following pretreatment with the thermophiles; responses varied widely for the individual materials. Although bioleaching had little effect on the preg robbing characteristics of the carbonaceous gold ores, cyanidation of the bioleached residues yielded higher gold recoveries than cyanidation of the native ore. By combining bioleaching with abiotic processes designed to inhibit preg robbing, gold recoveries of 83-98% were obtained from carbonaceous ores yielding 10-50% gold recovery by direct cyanidation.

Jan 1, 1987

By A. E. Isaacson

The U.S. Bureau of Mines is investigating a systems approach to metals recovery from leach liquors produced by in situ leach mining techniques. A successful in situ leaching process requires a thorough under-standing of the complex interrelationships that exist between leaching chemistry and metals recovery. Laboratory research is addressing these interrelationships in the solution mining of a copper oxide deposit. Laboratory tests have been conducted to gather baseline data related to the design and operation of continuous leaching-solvent extraction-electrowinning circuits. This paper addresses the findings of the baseline studies. Specific results include the characterization of simulated in situ leach liquors produced by leaching chrysocolla and chrysocolla-atacamite-bearing copper ores. Metal recovery procedures, utilizing four commercial solvent extraction reagents, are also characterized, and potentially troublesome leach liquor contaminants that may complicate waste management procedures are identified.

Jan 1, 1990

By A. B. Cecala

Two recent Bureau studies evaluated workers' dust exposures in automated pallet loading processes. The first study involved a Bureau designed dust control system using a push-pull ventilation technique. The unit was shown to reduce workers' dust exposures by 76% during pallet loading at a ground silica operation. A hydraulic lift table was used to automate the bag stacking process; this kept the loading height constant throughout the entire pallet loading cycle. The second study evaluated different commercial automated pallet loading systems. These systems automatically stack the bags onto pallets, shrink wrap the pallets, and deliver the pallets to a fork lift pickup location. Results from a ground silica evaluation site indicated respirable dust samples taken were below the Threshold Limit Value (TLV) as established by the Mine Safety and Health Administration (MSHA).

Jan 1, 1990

By R. K. Mehta

This paper presents the application of a simple genetic algorithm (SGA) to a coal slurry grinding process in order to find the optimum set of conditions under which the desired slurry properties can be attained. The operating parameters of the process were; slurry % solids, dispersant dosage, ball size, and mill speed. The optimization algorithm, which is based upon the mechanics of natural genetics, was used to find near-global optimum points specific to responses measured In terms of fineness, specific energy consumption, viscosity coefficient, and viscosity exponent. In order to minimize the viscosity of the slurry and simultaneously achieve a condition of maximum packing density, optimization was carried out by the penalty method using an overall objective function incorporating several responses. Computer results and analysis demonstrate the ability of the genetic algorithm to perform better than a traditional technique such as response surface methodology (RSM) and to rapidly locate "the global optimum".

Jan 1, 1992

By R. R. Guzman

In this study, the "Mine Project Risk Management" methodology, MPRM (Botin et al. 2011), has been applied to characterize the sources of uncertainty and to quantify risk in the mining engineering stages of Block Caving mining method. As the result, rock mass caveability and ore fragmentation were identified as the two most relevant parameters of this process and a methodological model has been developed to quantify the risk associated to each of these two parameters. Furthermore, the applicability of the proposed model has been validated using as a case study the Chuquicamata Underground Mine Project in Chile.

Feb 23, 2014

By Michael Clar

Total suspended solids (TSS), generally referred to simply as sediment, is one of the four major parameters of water pollution associated with surface mining activities. The other three para¬meters are iron, manganese and pH. Currently the Environmental Protection Agency (EPA) is in the process of developing and implement¬ing effluent limitations for these pollutants pursuant to section 301 of the Federal Water Pollution Control Act Amendments of 1972, 33 USC 1811.1 To date, effluent guidelines for existing point sources have been published, and guidelines for new sources are forthcoming. The effluent limits which have already been developed for TSS have been subjected to some controversy.1 Some industry spokesmen have indicated that they may be unable to meet these effluent limitation guidelines for TSS. The industry claims that in certain areas the suggested limit is unattainable since high suspended solid loads already exist in streams due to numerous and various sources of nonpoint pollution which include agriculture, silviculture and urban construction for which no TSS effluent limits have been set. An opposite viewpoint asserts that the TSS limitations are too lenient since permit data from the Regions (U.S. EPA Regions) indicates present compliance for several companies under more stringent TSS limits. The experience at the Centralia mine in Washington is one example.2

Jan 1, 1977

By G. T. Lineberry

The Work Crew Performance Model (WCPM) is a method for designing, implementing, and evaluating? performance improvement strategies for machine operators and other mining personnel. The WCPM offers a practical approach for measuring job proficiency and identifying costly behaviors. It enables interventions aimed at performance improvement, especially training, to be assessed monetarily. Two interrelated elements of the WCPM are emphasized: observational techniques for establishing performance baselines and measuring performance outcomes and cost linkages between job competencies and measures related to profitability. Inter-and intra-subject differences in performance-related behaviors of regular and incidental shuttle car operators were detected during field validation of the WCPM. Downtime data were used as outcome measures to test linkages between performance error rates and cost consequences. Use of a simulation program for analyzing continuous mining face operations showed how common shuttle car operating parameters (e.g., payload, tram rate) can be used as cost-conscious indicators of performance variability and therefore as targets for performance improvement.

Jan 1, 1994

By Georgene Renner

Due to disturbance of their traditional roosts, caves and tree hollows, more than half of the 44 bat species found in the United States and Canada now live in abandoned and inactive underground mines. The North American Bats and Mines Project was created two years ago by Bat Conservation International Inc. (BCI) in Austin, TX and the Bureau of Land Management (BLM) in response to the issue of mine closure and bat habitat. The partnership provides national coordination among government and private agencies and the mining industry to minimize the loss of bats living in mines. It also trains land managers on how to conduct cost-effective mine assessment and closure to protect both bats and people.

Jan 1, 1996

By J. D. McKay

Flotation columns have been readily accepted for use in most sulfide flotation plants; however, recently columns are being used in many other areas. Recent improvements in design methodologies have overcome many operating problems and led to improvements in metallurgy. In addition, physical improvements in column design have simplified their operation while leading to better control. The Turbo-Air External Bubble Generator has provided a method for bubble size control and variation in air holdup and carrying capacity. These have enabled commercial operations to improve grades and recoveries by optimizing performance.

Jan 1, 1990