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By D. D. Lauriski

The Mining Division of Utah Power and Light Company is located in the coal fields of southeastern Utah -main office in Huntington, Utah. The Division will produce 6.5 million tons of low sulfur steam coal in 1988, making UP&L the largest underground mining operation west of the Mississippi. Coal is mined from three underground mines utilizing continuous miner and longwall mining methods. All coal produced by the Mining Division is utilized at UP&L's two largest steam-electric power plants, the Hunter and Huntington plants with a combined capability of 1,995,000 Kw. At UP&L we believe that to achieve success a company must have clearly defined goals which are understood, communicated and shared at each level of operation. We have also found from experience that a safe operation is generally an efficient and productive operation. As a Division, we have established a goal to achieve the safest, most efficient operation in the country. This is an ambitious goal. To achieve such a goal requires real commitment and a safety/training program capable of achieving needed results. The following is an overview of the program we have established at UP&L which has enabled us to reduce our accident frequency rate from over 40 in 1980 to 8.00 at present, as illustrated in Figure 1.

Jan 1, 1989

By M. Karmis

The determination of the surface area which may be impacted by underground mining is an important consideration in subsidence engineering. A number of parameters have been utilized to identify this influence area, most notably the angles of draw and break. This paper discusses the implications of selecting an appropriate "damage angle" for defining a potential damage area due to mining, within which surface structures may be impacted Furthermore, the influence of both mining and geological factors, such as mining width and depth and overburden lithology, on this angle is examined, using the Surface Deformation Prediction System (S.D.P.S) software. Finally, recommendations are given for applying these concepts in subsidence control.

Jan 1, 1994

By K. Zabrusky

Estimation of high grade epithermal vein deposits can present challenges in correctly representing the continuity of grade within an undulating structure. One solution to this problem is to use dynamic anisotropy to follow local variations in the strike and dip of veins. Dynamic anisotropy (D.A.) allows the search parameters to change block by block throughout the model to account for the local variations. Presented here is a study of a vein that changes orientation down-dip. A traditional resource estimate using one search ellipse orientation was performed. The resulting estimated grades did not accurately reflect those of the sample data. Using a search ellipse with an average value for the two distinct dips caused the grade estimation to be less representative than desired. Rather than performing domain-based analysis with different search ellipses, the issue was corrected by using Datamine Studio 3?s D.A. function. The 3D vein trend was used to estimate the dip and dip direction of the vein in each block. The resulting D.A.-estimated model follows the two dip trends of the vein. This software makes a previously tedious task faster, and allows for more accurate estimations.

Feb 27, 2013

When the Middle Ages were drawing to an end and Rotterdam, then still a small fishing port, began to extend its trade relations to continental ports handling general cargo, a development was initiated which was to give Rotterdam a predominant position in maritime traffic in Europe 300 years later. Despite many setbacks and the silting up of the mouths of the Rhine and Meuse rivers, the port experienced a new rise towards the end of the previous century after the dunes at Hook of Holland had been cut through as planned by Dutch engineer Caland. With its favourable location in the mouth area of the Rhine and a hinterland opened up by waterways it was merely a matter of the city council pursuing a far-sighted policy to make the best of these natural advantages. Thus new port installations were erected on the southern bank of the Meuse in the first quarter of this century, which were expanded in the course of the subsequent decades. The New Waterway became the main artery for industrial enterprises, in particular oil industries, which sprang up along its banks (picture 1). Whereas 30 years ago Rotterdam's Waalhaven, with its new jettees for general cargo and mainly bulk goods, was still one of the most modern terminals, the growing size of ships, which increased by leaps and bounds for tankers, in particular towards the end of the 'fifties, necessitated much larger harbour facilities built further and further towards deep water.

Jan 1, 1972

By Kevin Andrews, Zach Agioutantis

Analysis of Coal Pillar Stability (ACPS) software, released in 2018, integrates numerous empirical pillar design techniques. The ACPS program incorporates methodologies originally available as design tools from the National Institute for Occupational Safety & Health (NIOSH), including Analysis of Longwall Pillar Stability (ALPS), Analysis of Retreat Mining Pillar Stability (ARMPS), Analysis of Multiple Seam Stability (AMSS), and concepts including Coal Mine Roof Rating (CMRR), the Mark-Bieniawski pillar formula, and pressure arch loading. The design methodologies that are the basis of ACPS were developed via analysis of significant amounts of real-world data and have been standards of the United States coal industry for decades. While there are empirical factors built into ACPS, making it ideal for use in U.S. coalfields, the concepts in the program have proven to be applicable in variable mine settings, and the software was developed to allow for user-based, site-specific modifications of key design inputs. Application of ACPS to cases outside the regions for which it was developed must be approached carefully, and continuous development of site-specific data is mandatory. A case study is presented involving the application of ACPS to assess pillar stability and assist future design for an underground lignite mine in Eastern Europe. Assessment of in-mine observations, review of the geology of the lignite mine, and evaluation of specific conditions associated with a failure event resulted in “calibration” of key input factors to ACPS. Scenarios evaluated with ACPS suggest that pillar strength and overburden depth are key factors for the determination of pillar stability and design in future areas.

Jun 25, 2024

By A. G. Yapo, T. W. Camm

"Mining plays a key role in the development of modern civilization as a source of essential raw materials and provider of essential fuels, producer of jobs and a factor in support of the international balance of monetary payment (Camm, 2014). Professionals in mining locate, develop, design and manage ore deposits in an environmentally safe and profitable manner. As mineral deposits become increasingly scarce, new challenges face the industry. A current trend is to an increased emphasis on underground mining techniques for deeper deposits. Operations are safer now than before as companies understand better their work environment and the importance of mining responsibly.A continual challenge for the industry is accurately reflecting the costs and selling price of ore. An enduring characteristic of mining is the situation where the market typically determines the price of a commodity; the main control a company has on the bottom line is to control the cost of production.An attempt to bring light and clarity to the cost of their business will give a better idea to investors on the true profitability of the mining business. Gold producers face this struggle to accurately reflect the cost of production while also seeking to attract the interest of the investment community (Hill, 2013). In order to have a consistent format to report on their production costs, leading gold producers, through their alliance inside the World Gold Council (WGC), worked on the adoption of a new cost framework: the all-in sustaining cost (AISC) and all-in cost (AIC).Since 1996, the traditional cash cost reporting has focused only on the mining and processing costs incurred in mining an ounce of gold, which included the costs of goods sold (labor, energy, and consumables costs) and royalties (Table 1). But cash cost reporting ignores many important aspects, like sustaining capital, general and administrative expenses and site rehabilitation at the end of the mine life (Whelan, 2013). The cash cost was used to attract many investors into the business. In fact, the high gross margin (sales minus cash costs) has been promoted in past decades by the industry instead of the net or operating margin. As a result, even when the gold price was high, nearly $61/g ($1,900/oz) in August 2011, gold producers were not reporting excessive profits in their cash flow/income statements, to the disappointment and incomprehension of investors (Milstead, 2014). The truth was simply that the other costs omitted in the traditional cash cost were reducing the apparent profits.The disconnect led to a need for more accurate cost reporting in order to win back investor confidence and provide better understanding of gold mining economics. In 2012, the senior gold mining companies, including Gold Fields, Barrick Gold Corp. and Newmont Mining Corp., worked with the WGC to develop a new measure. This resulted in the June 2013 publication of the new framework AISC and AIC, which has been widely embraced by the sector since Jan. 1, 2014 (WGC, 2013).The adoption of the new cost template would have the dilemma of showing the real profitability of gold mine properties, which might alleviate taxes from governments and legislators, but it might also scare off investors toward more lucrative industries if not winning back their confidence."

Jan 9, 2017

By Edward S. Plotkin, Joseph D. Guertin

In a continuing effort to upgrade tunnel design and construction practice, the New York City Transit Authority sponsored a geotechnical monitoring program on a recently completed section of the E. 63rd Street line in mid-town Manhattan. The purpose of the program was to document rock behavior as well as temporary and final rock support systems to provide a possible basis for either confirmation or modificification to design methods and construction specifications. This paper describes those portions of the study associated with rock behavior and temporary support systems. The entire study included monitoring of rock movements above the tunnel as well as adjacent to a 36.6m (120 ft) shaft, monitoring of stresses in steel ribs, monitoring of loads in rock bolts in two test sections and monitoring of stresses in the final concrete lining. PROJECT DESCRIPTION Route 131-A, Section 4 is located in mid-town Manhattan extending from under the Central-Park Zoo on Fifth Avenue eastward under 63rd Street to the end of contract between Madison and Park Avenue. Figure 1 is a Project Locus Map. The contract included approximately 355m (1165 l.f.) of 4 track tunnel(13.4m (44 ft) wide by 13.7m (45 ft) high excavated dimensions) plus a 22.9m (75 ft) by 19.8m (65 ft) by 36.6m (120 ft) deep ventilation shaft. The entire tunnel and most of the excavation shaft was excavated in metamorphic rock, known locally as the Manhattan Schist. The depth to tunnel invert varied from approximately 27.4m (90 ft) at the west end of the contract to 35.Om (115 ft) at the east end. Rock cover above the excavated crown varied from approximately 6.7m (22 ft) at the approximate mid-point of the contract to 18.9m (62 ft) at the western end. A plan view and interpreted geologic profile are illus-

Jan 1, 1979

By d&apos, L. R. Fletcher, Andrea. D. V., M. A. Peltier

The Bureau of Mines analyzed coal mine blasting accident data obtained from the Mine Safety and Health Administration (MSHA), U.S. Department of Labor. The data were examined to determine the causes, frequency, and severity of accidents in an effort to point out the most dangerous aspects of coal mine blasting. Accident data for the 14 years from 1971 through 1984 show that there has been a total of 43 fatal and 926 nonfatal blasting accident victims in surface and under- ground coal mining. This is an average of 3.1 fatal and 66.1 non- fatal injuries each year. Underground coal mining accounted for 60.5% of the fatal and 78.7% of the nonfatal accidents involving explosives and breaking agents in coal mining. In addition, since 1970 there have been 53 fatal and 20 nonfatal injuries that occurred when explosives were the ignition source for dust and/or methane explosions in underground mines. Abstracts from 297 accidents that occurred from 1978 through 1984 were also examined to determine accident causes. Most accidents occur during scheduled blasting, and failure of the blast area security system is the leading cause. Blast area security problems in surface mining are failure to clear the blast zone, failure of personnel to follow instructions, inadequate guarding, and failure to retreat to a safe location and/or take adequate cover. Other common causes in surface mining include premature blasts, excessive flyrock, and misfires. In addition to the above causes, accidents in underground coal mining can be due to rockfalls triggered by the blast, unexpected breakthroughs, fumes, and incidents associated with Airdox-type systems.

Jan 1, 1986

By Alafara A. Baba, Yakubu A. Dallatu, Kehinde I. Omoniyi, Shemang Y. Chindo, Edith B. Agbaji

With the rise in global demand for pure copper, there is an urgent need to consider the processing of low-grade chalcopyrite ores. Ammoniacal leaching solutions have been reported as effective and efficient leachants for the dissolution of chalcopyrite. This work reports on different parameters that influence the leaching kinetics of a Nigerian chalcopyrite-rich siderite ore obtained from the Wase local government area of Plateau state, Nigeria, and assayed as 11.30 weight percent copper.

May 1, 2023

From some of the largest tunnel projects in the some of the most vibrant cities, to smaller projects in remote corners of the globe, the Robbins Co. announced two tunneling projects in which its tunnel boring machines will be used. Robbins earth pressure balance (EPB) machines undercut Downtown Zhengzhou. Zhengzhou, a city of 7 million people, is set to become a crossroads for rail commerce in China. The country?s future main routes, traveling between Beijing and Guangzhou (North-South), and between Xuzhou and Lanzhou (East-West), will intersect in the city. The plan includes up to four rail lines in Zhengzhou itself, which will eventually link up to the national lines. Excavation of Zhengzhou Metro?s new Line 1 tunnels began on Sept. 28, 2010, when the first of two 6.3-m (20.7-ft) diameter Robbins earth pressure balance (EPB) machines was launched from a 16-m- (52-ft-) deep shaft.

Jan 1, 2010

By David K. Sitler

Continuing advances in manufactured diamond materials used in rock cutting tools have created a new generation of high production tools for mining. This paper will review the three major manufactured diamond products available for the mining industry as supplied by General Electric Company, Specialty Materials Department, and examine the ways in which these materials are employed. As an integral part of this examination, the economic impact of manufactured diamond tools will be evaluated. Time and again, one will find that the premium price of these tools is economically justified when compared to traditional tools.

Jan 1, 1985

By MYRIAM FRANCOEUR, JOHN R.R. BOWLING, ADAM MCFADDEN

As duct-fan systems push the envelope of power, length and cost, their design calls for a more comprehensive technoeconomic analysis to ensure they deliver the expected results without failure and cost overrun. This work explores the numerous factors to include in the design of an extensive (semi-)rigid duct-fan system. Besides delivering a given airflow, the system must satisfy component limitations and power constraints during its lifetime. We evaluate the assumptions underlying the positioning of in-line booster fans in a long gapless duct-fan system and propose a strategy for specifying the location and blade pitch of successive booster fans to prevent system failure due to a partial vacuum.

Oct 1, 2022

By Jr. Chesson

"Phosphate" is a misnomer as often used. The word is increasingly used to refer to any material containing phosphorus - an element essential to any form of life. Phosphate rock, a mineral - fluorapitate - is recovered from Florida's sedimentary deposits in particle sires ranging from 0.1 to 13.0 millimeter. This product of mining, washing, screening, and flotation is commonly called "phosphate". Its phosphorus content, measured and reported as P2O5, varies from 29% to 35%, and is essentially insoluble. "Phosphate" is also used to describe products containing soluble phosphorus obtained from acidulation of phosphate rock with mineral acids; primarily, sulfuric acid. Many miners have nearby chemical plants wherein phosphate rock is converted into upgraded products such as phosphoric acid, superphosohates, and ammonium phosphates with 45% to 70% P205, soluble and suitable for use as fertilizer. The rock and upgraded products are all commonly called "phosphate"; the plants, "phosphate plants' and the producers collectively are known as the "phosphate industry". The public in Central Florida generally loses identification of the individual operators that include major corporations such as IMC. Williams Companies, W.R. Grace, Mobil, Embark, U.S. Steel, Borden, American Cyanamid and others. They all become just a "phosphate company".

Jan 1, 1978

By H. E. Cross

In a minerals-recovery context, the object of exercising control over milling operations must be threefold, 1) To achieve maximum recovery at 2) minimum operating costs and 3) making maximum use of installed equipment, Milling is one of a sequence of operations which have as their objective the economic recovery of minerals from mined ores, All operations in the sequence are interdependent and each is both influenced by and itself affects all other unit processes. The part which grinding plays in achieving each of the above objectives is indicated in the following analysis: In South Africa, the most important mining operations are still the gold mines, A vast reservoir of knowledge and experience in treating the Witwatersrand and associated ores has been accumulated. and recoveries are consistently high, However residue values do vary and frequently this is due to fluctuations in the degree of grind, The significance of changes in residue values is indicated by the following example: On a modern mine, the residue values varied from 0,25 to 0,33 dwi; per 2000 lb, during a period of 6 months, The cash value of the gold thus lost varied therefore between $0.44 and $0.58 per 2000 lb, ton. A residue which assays 0.30 dwt per ton would contain approximately 0.26 dwt as undissolved gold and 0,040 dwt per ton as dissolved gold present in residual solution after filtration. This dissolved gold loss is a function of efficiency of filtration and varies from 0.030 to 0,.070 dwt per ton of residue.

Jan 1, 1970

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

The effectiveness of the grouting of saturated, fractured rock in the vicinity of underground workings depends to a great extent on the correct interpretation of the specific hydrogeological conditions at the site. During the planning of grouting operations, calculations of the hydrogeologic co-efficients and of the parameters of the isolating grout curtain(s) and the procedures for forming the curtain(s) must be based on valid hydrogeologic characteristics of the fracture system of the rock within each hydrostratigraphic unit (Anon., 1976). This chapter presents a discussion of the background information that must be collected for these purposes. Details of testing are presented in Chapter 3. The general design of new or the reconstruction of existing underground workings requires a broadly based organization having the expertise to develop a grouting operations plan once it acquires the necessary information. The needed information includes: 1) general information about the hydrogeologic section, 2) the engineering design of the underground workings, 3) the geology of the region, 4) the hydrochemistry of the ground water, 5) the hydraulic properties of the rock, 6) the characterization of all gases present, and 7) characterization of the rock's physical-mechanical properties which is necessary to avoid or control hydrofracturing . The geological documentation portion of the hydrogeological investigation is prepared based on the results of geologic mapping, geophysical surveys and on geo-exploratory operations at a regional and local scale. Geological data from the excavation of other underground workings in adjacent areas of the region is also included. Finally the results of site specific investigations in boreholes constructed at the site of the proposed underground activity are incorporated. A section of the preliminary report entitled "General Information about the Project Site" patterned after the parent STG guidance document on this subject must be com- piled based on the contents of geological reports and on the general construction plan for a new project or the plan for reconstruction of an existing operation. This section of the preliminary report must contain concise information about the conditions under which the planned grouting operations are to be conducted. The information must cover the geo- graphic, administrative, and economic subject areas also. Information about sources of electrical power, heat and water supplies, the presence and characteristics of local construction materials suitable for making grout (particularly clay and cement for the clay-based grout), transportation, and the status of communication lines and other services must be included in this section. Map scales for this section should be on the order of 1:25,000. The technical characterization of planned underground workings is presented in a project report chapter called "General Construction Plan for a New or the Restoration of an Old Operation. " The characterization comprises concise information about the purpose of the workings, the planned depths (for shafts) and the length (for horizontal and inclined workings), the inside and excavated diameters (for shafts), the cross-sectional area (for inclined and horizontal workings), and the face and mouth markers. If excavated underground workings exist in the region, then a concise description of them must be provided. The characterization of all excavations and all operational conditions must be specified. The location within the general structure of the proposed operation is specified. Flow charts must be included in this section that show: 1) the plan for opening the deposit, 2) the plans of the mining operations, and 3) the planned geological sections as they relate to the main workings. These graphical flow charts and appendices are drawn in scales of 1:2000 or 1:5000. 2.1 GEOLOGICAL CHARACTERIZATION The geological characterization of a site of proposed underground workings includes the following principal subject areas: stratigraphy, lithology, structural geology and a characterization of the status of fracturing. 2.1.1 STRATIGRAPHY AND LITHOLOGY A description of the geological section of the rocks to be intersected by the planned underground workings is complied on the basis of: 1) research data derived from core extracted from exploratory boreholes and monitoring boreholes, 2) the documentation and mapping of all natural out- crops in the region, 3) the data from all existing under-ground workings in the regions where operations are being canied out already, along with data from adjacent regions, 4) the data from surface and borehole geophysical investigations (standard and specially developed logging methods, and 5) regional stratigraphy. The geological description of the rock must express the maximum detail possible. The description provides the name of the rock, the granulometric composition (for fragmented rock), the composition and type of stratification, the drilling characteristics of the rock, a visual estimate of porosity and density for each stratum identified, the karstic

Jan 1, 1993

By Werner Burger

The Hallandsås project with a long history, first started in 1991, is well known in the tunneling community. In the past it has been stopped twice for technical and environmental reasons. The third attempt started in 2004 using a dual mode rock TBM. The heterogeneous highly fractured and abrasive rock mass as well as large areas of water bearing zones present most difficult subsurface conditions. The tunneling concept is based on the use of watertight segmental lining and a TBM able to operate in open mode, possibilities for extensive pre excavation grouting and high pressure closed mode operation up to 13 bar to cover exceptional conditions.

By M. L. Harris

In underground mines, coal dust explosions are prevented by the addition of rock dust sufficient to render the coal dust inert. The National Institute for Occupational Safety and Health (NIOSH) has developed a hand-held instrument that uses optical reflectance to measure the explosibility of a rock dust and coal dust mixture. This instrument is called the Coal Dust Explosibility Meter (CDEM). In this study, NIOSH personnel accompanied Mine Safety and Health Administration (MSHA) inspectors on their routine band surveys in five and three underground coal mines in MSHA District 2 (PA) and District 11 (AL), respectively. While underground, NIOSH personnel and MSHA inspectors used the CDEM to assess the explosibilities of the dust samples. The values of percent incombustible content (% IC) determined by the CDEM agreed well with those obtained later by low temperature ashing (LTA) in both MSHA and NIOSH laboratories. Further, the meter identified some samples as potentially explosible that LTA analysis had found to possess sufficient rock dust for inerting. The CDEM provides more information on the hazards in the mine. Rapid identification of areas with explosible dust mixtures using the CDEM allows for immediate intervention rather than a wait of several weeks for laboratory analysis.

Jan 1, 2008

By R. E. Ray

Compared to conventional fully ducted axial and centrifugal fan systems, jet fans can offer a number of advantages for control of smoke during fire emergencies and dilution of diesel engine exhaust products in vehicular and rail tunnels. The success of jet fan applications is the result of a balance between the temperature de-rating of the fan, buoyancy forces and the installation momentum transfer efficiency. This paper provides a case study of a unique application of vertically-mounted jet fans in ventilation shafts used to provide both emergency ventilation and pollution control for an overbuild created by the construction of a series of commercial high-rise residential buildings over a portion of an existing passenger rail line. A detailed evaluation of a set of shafts for one building is presented, including a discussion of the calculation methods used to estimate the required jet fan capacity and the results of the subsequent numerical analysis using Computational Fluid Dynamics to simulate the performance of the jet fans during train car fire emergencies.

Jan 1, 2009

By Barbara J. Arnold

A coal's size distribution, clay content and moisture content can affect its handling behavior, but the combined effects of these properties and the effects of other properties are not known. Research underway at CQ Inc.' s (formerly EPRI' S) Coal Quality Development Center (CQOC) and at Iowa State University (ISU) will answer these questions as part of a four-year project to develop a coal handleability index for utilities to use when specifying coals. This paper will present preliminary data from the first year of the project, which focused on obtaining data on the chemical and physical properties of various coals and their measured handling properties. Additionally, size, ash and moisture analyses and shear test data for several coals used at one power plant will be presented along with correlations between these physical and chemical properties and the measured handling properties. These data lead to the conclusion that, while moisture content-is the most important variable, the amount of -325M (-0.044 mm) coal fines is a significant factor in determining coal handling behavior.

Jan 1, 1990

Current scrubber capacities vary from 1.89 to 4.72 m3/s (4,000 to 10,000 cfm), and there is interest in using scrubbers with capacities up to 6.61 m3/s (14,000 cfm). This paper describes research to compare the effectiveness of blowing and exhausting face ventilation systems using high-capacity scrubbers with flows up to 6.61 m3/s. Tests were conducted in a surface ventilation gallery with exhaust and blowing systems operating under similar conditions. The mining machine was equipped with a machine-mounted scrubber. Methane gas was released at constant flow at the mining face and measured at several face locations. Effectiveness of exhausting and blowing systems was compared by determining average face methane concentrations. For each operating condition tested, blowing ventilation was more effective than exhausting for controlling face methane levels. Raising scrubber flow to 6.61 m3/s reduced methane levels for both blowing and exhausting systems.

Jan 1, 1996