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By Leonard B. Rothfeld

For many years, pulverized coal (PC) boilers in utility power plants have been the dominant market for domestic coal. Today, two new coal utilization technologies challenge the PC boiler's dominance. Atmospheric fluidized bed combustion (AFBC) and "coal gasification/combined cycle" (GCC) stand on the verge of commercial demonstration in the utility environment at a scale of 100 MW. Developed over the past decade, these technologies respond to the demands for cleaner ways to burn coal and for more flexibility in fuel supply. In the near term, these are the "clean coal" technologies most likely to have a significant impact, because they are ready for commercial application. As for environmental acceptability, consider that just a few years ago one of the environmental slogans was "no coal in California." Indeed, the only large quantities of coal above ground in California at that time were in transit on the way to Asia. Today, thanks to new technology, we can point to two operational coal-burning plants in California and one in the works: * Cool Water GCC demonstration plant (100 MW) * California Portland Cement AFBC commercial cogeneration, near Riverside (190 000 lb/hr steam) * Energy Factors AFBC commercial cogeneration at Stockton, to be operational 1988 (44 MW)

Jan 1, 1987

By T. W. Newell

Small tonnage ore bodies can be developed at a profit on a short life basis. Such is the case of the Bardon Mine in. the Big Indian Mining District in San Juan County. Utah. Faced with a small initial tonnage of high grade uranium ore, the Shattuck Denn Mining Corporation Engineers developed some new ideas for sinking the shaft and planned extraction to warrant the capital risk to mine a limited reserve. The Bardon Mine is located fifty miles southeast of Moab, Utah in the south end of the Big Indian Mining -district. Shattuck Denn Company, a wholly owned subsidiary of the Shattuck Denn Mining Corporation, manages and operates the property under an operating agreement with Kerr-McGee Oil Industries, Inc. of. Oklahoma City. Oklahoma, and Anderson Development Corporation of Albuquerque, New Mexico. Based. on Kerr-McGee drilling., a tabular ore body about 350 feet long by 250 feet wide with an average thickness in excess of seven feet was indicated.- The ore body strikes easterly-westerly and dips from nine to twelve degrees to the south. Uraninite is the dominant uranium ore mineral associated with vanadium. The ore occurs in an arkosic conglomeratic sandstone with some interfingering of mudstone and shale in the Mossback member of the Chinle formation in contact with the underlying Cutler formation. The ore horizon is overlain with 40 to 60 feet of mudstone and shale. Fortunately, the back. immediately over the ore is a reasonable competent shaley sandstone which has made a fairly good. environment for roof bolting.

Jan 1, 1960

By Nilabjendu Ghosh, Satyendra Kumar Singh, Gautam Banerjee, Harshit Agrawal

High-production methods like longwall mining with hydraulic powered supports are necessary to increase underground coal production in India. Longwall mining had a mixed success record for Indian geo-mining conditions. In this paper, an analysis is presented to optimally design an array of chain pillars in multi-seam longwall mining panels in the deepest coal mine in India. The study found that a chain pillar of 80-m width and 195-m length is necessary for long-term stability without any reinforcement. It was also observed that an optimum chain pillar can be designed by providing suitable side reinforcement (side bolting) which will reduce the chain pillar dimensions to 55-m width and 160-m length. Optimum design of chain pillars will reduce the coal locked up in these chain pillars by ~ 77%. This will also reduce the gestation period of longwall mining panel development. This paper also evaluates the maximum tensile subsidence strain induced at the surface and finds that the values are within the safe working limit of 3 mm/m. Thus, this paper finds direct application in the design of future multi-seam retreating longwall mining panels in Indian geo-mining conditions.

By Ali Hafiz, Aidin Golrokh, Tom Iseley, Kaz Tabrizi, Saleh Behbahani

In the USA many highway tunnels were built during the 1930s through 1960s. This indicates that these tunnels have exceeded their intended design service life. Based on the initial tunnel inventory conducted jointly by the Federal Highway Administration (FHWA) and the Federal Transit Administration (FTA), more than 526 highway tunnels have been identified in the USA. For understanding the condition of the tunnels and risks associated with deteriorating conditions, comprehensive condition assessments are necessary to mitigate risk and remediate works as required. Monitoring the condition and rate of deterioration of tunnels is vital for timely tunnel maintenance and rehabilitation to avoid sudden tunnel collapse. This session will explain the necessary steps for tunnel inspection and review some of the state of the practice information on tunnel inspection techniques.

Jun 13, 2023

By W. W. Mason

The United States began exporting coal in the late 1800'5, at first in very small quantities to Canada and beginning in 1897 and 1896, to the east coast of South America. Shipments to European countries began on a very limited basis in 1902 and these shipments increased gradually until World War One when shipments overseas increased from the 8 million tons per year level to 22 million tons. After the war exports dropped as fast as they had increased and, with the exception of exports to Canada, remained at very low levels until just after World War 11 when the United States again emerged as a major coal exporter. World War II left the coal industries of Europe in ruin. As the United States was the only country able to supply the large quantities of coal at reasonable prices needed for reconstruction of the European economy, the U. S. coal exports overseas expanded rapidly to 42.5 million tons in 1947. Additionally, we shipped 25 -2 million tons of coal to Canada In that year for a total export of 68.7 million tons. Unfortunately, that level was not reached again until 1957 when exports reached an all-time high of 76 .4 million tons- -a high I might add that has not been reached since.

Jan 1, 1980

By Gordon A. Gross

Banded siliceous manganese-iron bearing sediments recognized as distinctive facies of Algoma type iron-formation constitute low grade resources of manganese in many countries. Manganiferous facies associated with oxide and carbonate facies of iron-formation have iron to manganese ratios ranging from 0.2 to 2 and commonly about one. Manganiferous facies up to 30 meters thick occurring separately or with other iron-formation facies are associated with cherts, carbonates, shales, turbidites, tuffs and lavas. Primary cherty manganiferous facies and their gondite metamorphic equivalents represent significant manganese resources and are protores for higher grade deposits derived by secondary enrichment processes.

Jan 1, 1982

By Patrick Shea

Old mine workings are found throughout the Western United Sates on lands administered by the U.S. Bureau of Land Management, U.S. Forest Service and private lands. Some of these mine workings date back to the late 1800s. There may be as many as 100,000 sites on lands administered by the National Park Service, U.S. Forest Service and Bureau of Land Management. The U.S. Department of the Interior has worked with the U.S. Geological Survey, the U.S. Forest Service, the U.S. Environmental Protection Agency, and western state governments to identify and prioritize these sites on Bureau of Land Management, National Park Service and U.S. Forest Service administered lands. This presentation will discuss the accomplishments we have made to date to clean up inactive and abandoned mine sites, focusing primarily on lands administered by the Bureau of Land Management.

Jan 1, 2000

By Sheldon P. Wimpfen

Sand and gravel has been, and will continue to be, our principal construction material. Most of us are familiar with the patterns of past growth. Today we will examine the present status of this vital industry. We shall also attempt to look into the future to see where it is going and to evaluate the constraints that are being imposed. Natural aggregates are among the lowest in value of all bulk industrial minerals. From the processing point of view, sand and gravel production is relatively simple since the products are sized materials obtained from a deposit of satisfactory physical soundness. They can be used either loose or bound to provide bulk, strength, or protection. One of the main uses of coarse aggregate is in concrete as a filling material. As a general rule, the coarse aggregate constitutes about three-quarters of the volume of concrete. The other main use for aggregate is as a roadstone or roadbase to provide protective and stabilizing bulk beneath the road surface. Also it is used in a mixture with petroleum products as the wearing course on top. The sand and gravel industry is geographically widespread. In general, the output of operations is directly proportional to the amount of construction in any area. A wide variety of other aggregates compete with sand and gravel, including crushed stone, blast-furnace slag, clinker, and artificial and natural lightweight materials.

Jan 1, 1972

By William Laird

In the process of mining coal today, our greatest asset, the coal miner, is faced with the indirect and direct consequence of underground mining operations. The indirect considerations may be the rank of the coal seam, the amount of overburden, geological factors, seam permeability and cracks. The introduction of newer, bigger and faster coal-producing face equipment having the capability to cut or rip through the bedding planes, cleats and micropores of the coal seam brings about rapid liberation of gas accompanied by greater concentrations of coal dust, has exerted a direct consideration and greater demand upon mine ventilation systems and dust control. The purpose of mine ventilation is to provide sufficient pure air to the miners working underground and to dilute, render harmless, and carry away all the dangerous and noxious gases. The mining operations which create coal dust are cod cutting, drilling, blasting, loading, hauling, dumping and movement of face equipment. The created fine dust causes the propagation of explosions. When quantities of coal dust with no methane present are raked in a sufficiently dense cloud in the presence of a source of ignition, an explosion is possible.

Jan 1, 1980

By C. Meyer, J. J. Eidel

Major gaps in understanding hydro- thermal systems remain after a century of studying fossil ore deposits and active geothermal areas. The periodically rejuvenated concept of "stacking" ore deposit types has never been verified by a continuous sample. Basal and marginal regions of both “fossil" and "active" hydrothermal systems normally lie beyond the limits of economic exploration, remaining inadequately exposed. Incomplete scientific under- standing of he vertical transitions clearly limits the efficacy of exploration programs for hydrothermal ores of all types. The Continental Scientific Drilling Committee's (CSDC) Panel on Mineral Resources has defined dedicated research objectives and add-on experiments to industry or government drill holes of opportunity.

Jan 1, 1988

By Ross Goodman, Jesse Salai

The Ohio River Tunnel Project encountered multiple unexpected geotechnical challenges such as crown and invert instability due to the overstress condition affecting the strata above, below, and in the tunnel alignment during and after TBM excavation along with the potential for methane inflow. This paper showcases how the orientation of a tunnel alignment has a significant impact on how in-situ geological stress can impact the excavation of a tunnel from the contractor’s point of view and how geological features influence gas inflow to the alignment over time.

Jun 13, 2021

By Greg Beckstrom

Minnesota is a major mining state. This statement is not a dream or stretch goal but is a fact. As reported in a recent edition of Mining Engineering magazine, Minnesota ranks as the third largest state in terms revenues generated from nonfuels mineral production. The vibrancy of the mining sector in Minnesota can be attributed to several factors. The northeastern corner of the state is home to Minnesota?s iron range, one of North America?s largest deposits of iron ore. Iron ore from Minnesota is a strategic resource that has been [ ] instrumental to the nation?s development ? 90 percent of the iron used to build ships and planes during World War II came from Minnesota. Taconite pellets now produced from openpit mines on the iron range are shipped to steel mills worldwide. The growing appetite for steel in China and India has reignited once moribund mining operations throughout the iron range.

Jan 1, 2012

By T. J. Close

On September 10, 1991, Secretary of the Department of Interior Manuel Lujan deleted the Silver Peak Range North Wilderness Study Area from the list of U.S. Bureau of Land Management lands in Nevada to be considered for wilderness designation. This decision was based in part on the U.S. Bureau of Mines mineral investigation of the wilderness study area which found that it has indications of precious metals resources. The following is a summary of the results of that mineral investigation. The study area lies between the Silver Peak and Dyer mining districts of west-central Nevada. The Silver Peak mining district, to the east, has a long mining history dating back to 1907 when precious-metals-bearing veins were discovered. The major producer in the Silver Peak district was Sunshine Mining Company's Sixteen-to-One silver mine. During the Bureau's study the Sixteen-to-One mine was operating; it has since been idled due to low silver prices. Precious metals-bearing veins were discovered in the Dyer district, to the west of the study area, in the 1860's. Mineral activity in Dyer district consisted mainly of prospecting. The Silver Peak study area itself has no mining history and contains only a few mining claims, but the Bureau examined 13 mineralized sites, most previously unknown and unclaimed. These sites are along two zones that cross the study area from the Silver Peak to the Dyer mining district. The two zones transect a volcanic center of fractured and altered rocks that contain epithermal veins of quartz, calcite, and jasperoid with gold, silver, and base metals. At the surface these veins are poorly defined and poorly mineralized. The more than forty veins examined in the study area are as thick as 17 feet and as long as 1,000 feet. Samples from surface exposures of these veins contained as much as 0.02 ounce per ton gold, 2.1 ounces per ton silver, 1.0 percent copper, 2.6 percent lead, and 0.4 percent zinc. Analyses of the Bureau data disclosed no vein large enough or of high enough grade to be classified a mineral resource. However, most do have indications of silver-and gold-bearing resources at depth. Subsurface exploration had to be done on the vein at the Sixteen-to-One mine to outline reserves (a vein averaging about 22 feet thick and containing 6-to 7-ounces per ton silver); the same is true of veins in the Silver Peak Range North Wilderness Study Area.

Jan 1, 1993

By Louis A. Sandbak

Drift excavation by boom-type roadheaders in the San Manuel and Kalamazoo sulfide copper ore bodies has been successfully demonstrated. Geomechanical rock classification in conjunction with detailed geologic mapping has been necessary to assess roadheader performance, and to predict advance rates in the varied rock classes in the San Manuel block caving mine. Rapid excavation and less fractured ground are obvious advantages of roadheader drift excavation over conventional drill and blast techniques. The geomechanical system of Engineers International (1984) can be an effective roadheader performance and ground support tool.

Jan 1, 1985

By Ditend Tesh, Godfrey Dzinomwa, Harmony K. Musiyarira

Namibia is known as water stressed country with a limited amount of fresh water. Therefore, the use of water is an important topic in the country’s development agenda. Water is a shared and finite resource, with high social, cultural, environmental and economic value. However, freshwater resources are under pressure from ore processing, industrialization, urbanization and the demands of a growing population. In Namibia, ore processing, coupled with the anticipated increase in water demand for human consumption and other uses, has created significant stress on the limited water resources of the country. This is critical in the mining industry as water remains typically the prime environmental medium (besides air) that is affected by mining activities. This study sought to investigate the strides made in water management in mining, especially in environmentally sensitive areas of Namibia. Most mining companies operate next or alongside farms, national parks and fishing areas. The overall objective of this research was to highlight the current practices in Namibia’s mineral industry operating in environmentally sensitive areas especially in areas where uranium is being mined and processed. The methodology consisted of comprehensive literature review, field visits to the case study areas, and comparative studies with best practices. This study shows that over a ten-year period, freshwater consumption was reduced by over 55% per tonne of milled ore in uranium mines, resulting in substantive financial savings as well as the delay in water augmentation through desalination. The strategies employed by the Namibian companies involve inclusive stakeholders’ engagement, recycling and reuse, and the minimization of water losses. The realization that the water challenge cannot be solved by any one party acting alone has been fundamental in ensuring environmental compliance within the mining industry in Namibia. Namibia’s industrial leaders have increasingly recognized that reducing the water footprint of mining activities must be one of the key performance indicators for management. The major finding of this study was that Namibia with its unique ecosystems, mineral reserves, and emerging industries can harness a wide range of resources both to improve the welfare of its citizens and to protect the integrity of its environment.

Jan 1, 2017

The first form of a surety bond was an honest handshake between two or more parties, agreeing to a decision and their personal guarantee of following through to completion. This has all changed. In 1895, the United States Treasury Department disclosed that $35 million worth of personal surety guarantees on file had become worthless. At that time, a law was passed, requiring all surety bonds, in favor of the United States, must be corporate surety bonds. Today, a surety bond is one of the nation's leading financial instruments used to guarantee the completion of an obligation.

Jan 1, 1989

By J. E. Lees

Advanced remote sensing can be a powerful new information tool to help private and public entities make better environmental and resource management decisions. However, some regulated entities are reluctant to develop or use this tool because of their concerns that it will lead to increased risks and costs of environmental legal liability. They fear that new ways of monitoring the environment will increase liability, undermine existing enforcement agreements, reopen compliance agreements, and generally provide a competitive disadvantage to early adopters by accelerating environmental cleanup costs. Others counter that the increased risks are marginal, and that several advantages outweigh these risks, including the opportunity to more effectively manage environmental operations, target and set priorities, measure and track management and compliance effectiveness, provide more defensible environmental assessments and baseline conditions, make and defend optimal siting decisions, and avoid or resolve environmental disputes. This paper offers strategic advice on ways regulated entities can enjoy the benefits of these powerful new information tools while mitigating down-side legal and compliance risks as much as possible.

Jan 1, 1999

By J. Pascoe, J. H. van Laar, J. H. Marais, F. J. L. Matthee

Advanced measurement and verification (M&V) is a process where the impact of an energy initiative is determined in real time. Data prediction models can be used to predict and compare energy consumption with a predetermined baseline. Deeplevel mines can benefit from advanced M&V as the impact of operational changes can be identified in real time. Ultimately, this can ensure that informed decisions are made regarding energy management based on the impact and severity of the occurrence. Previous studies on advanced M&V do not account for operational changes to the model’s baseline. These changes can significantly impact the performance of both the mine and related activities. The aim of this study is to propose a method that can accurately predict the energy consumption of a deep-level mine regardless of operational changes. To achieve this objective, nine different data predictive modelling techniques were considered. The proposed method is based on the Moving Average (MA) modelling technique due to its simplicity, flexibility, and rapid development time. The coefficient of variation for the root mean square error (CV(RMSE)) was used to statistically analyse the modelling error. If the predictions exhibit an unsatisfactory CV(RMSE), the model dynamically adjusts to reduce the prediction error. The model was developed to adapt to operational changes in scenarios where the standard model becomes irrelevant. The method developed in this study was able to predict the future energy consumption of deep-level mines with an accuracy of 99%, improving the mine’s energy and finance management.

Dec 13, 2023

By Todd S. Harris

Industrial minerals or non-metallic minerals are loosely used terms applied to a diverse assortment of materials which, in many cases, have nothing more in common other than the fact that they are neither metals nor fuel minerals. To help bring order to this otherwise random assortment of minerals, we have grouped these materials into two main categories; chemical and physical minerals, and nine sub-categories based on end-use applications as shown in Table 1. Chemical minerals are products which are principally used for the specific chemical elements they contain, whereas physical minerals are products which are used to meet specific performance specifications. The latter part of the 1970?s, in particular 1978, were considered peak years in terms of production and sales for many industries, By using 1978 as a base year, we can evaluate wherethese markets stand today after the recession of the early 1980's and the recovery which began several years ago. From this historical overview and appraisal of the current situation, various assumptions can be drawn as to which markets are expected to perform well into the 1990's.

Jan 1, 1987

By A. Nieto

This article is a review of previous discussions about underground mining method selection and classification with the purpose to clearly define and classify the two groups of variables (indicators) involved in the mining selection process: key deposit indicators (KDIs) and key mining method indicators (KMIs). This paper provides a simple and clear approach for the classification and selection of a feasible underground mining method based on a predetermined set of favorable deposit characteristics, which are defined as key deposit indictors (KDIs). This article also gives a summary of the key advantages and disadvantages associated with every underground mining method based on their key mining indicators (KMIs). The selection method given in this paper is based on defining field KDIs and comparing them to the KDIs that are favorable to every considered mining method. By cross validating a matrix of favorable KDIs, the paper presents a simple approach to rank several underground mining methods using a scale from favorable to less favorable accordingly to the ore deposit characteristics (KDIs). KMIs are used to further complement KDI rankings by analyzing every method’s KMI performance based on the expected productivity of the mining operation being considered. To further assist the reader through the selection process, this paper gives basic sketches representing each of the primary underground mining methods discussed in this paper. Each method is given using the same 3D isometric view as spatial reference to assist the reader with visual interpretation and comparison between methods.

Jan 1, 2010