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By James G. Tilton

Throughout the world, sedimentary basins are exploited for many different minerals. Frequently, the extractive methods conflict with one another. A case in point is the proximity of oil and gas operations and the mining of coal. Generally, the interference between the two industries lies in the fact that the reserves over- lie or underlie one another. Mining of coal generally is developed on a rectangular pattern in a horizontal mode while oil and gas drilling is developed on a radial pattern in a vertical mode. Coal mining has exhausted vast acreages in various basins with many of those basins being drilled for oil and gas. Those existing wells create problems by requiring the unrecoverable coal pillars to support the well bore, or to make special provisions in order to mine through an existing well. The system works ... more or less; but there are little or no provisions made for additional drilling unless the vast majority of those new wells are drilled through mined-out sections (gob) of those mines. Many states have rules and regulations governing the drilling of oil and gas wells through gob; but, some companies and some regulatory agencies or personnel have deemed such drilling as a hazard to the mining operations. This paper explores the history, technical standards, and safety aspects of drilling oil and gas wells though the gob of worked-out and active mines. It is the opinion of the author that such drilling can be conducted safely while eliminating the re- quired changes in mine projections and the loss of recoverable coal in the form of well pillars.

Jan 1, 1997

By Peter T. Luckie

Coal represents 80% of the fuel reserves of this country, yet only 20% of the fuel consumption. In order to change this ridiculous situation, a realistic coal utilization roadmap needs to be drawn to show how we go from where we are to where we want to be. The completion of the roadways will require the building of research bridges. The research bridges on the coal processing section of the superhighway should be built to process 500pm by 100pm rather than 25pm by 0 raw coal . Particular emphasis should be on middlings processing and total plant performance. The superhighway should be layed out by a team of fuel, coal preparation and mining engineers.

Jan 1, 1988

By C. Tsiouvaras

Restoration of bauxite mining areas constitutes a difficult issue to address due to the destruction of the vegetation and soil decay of the excavated area. In this study woody species growth, in relation to altitude, heavy metal concentrations and mechanical texture of the underlying mining waste, were investigated. The research was implemented on restored sites of a bauxite mine in the Fokida Prefecture of Greece. These sites were located in three different elevations and the restoration took place in two phases, in 2001 and 1996. Heavy metals measurements showed some correlation among the different metals, whereas their concentration was also associated with plant growth parameters.

Jan 1, 2007

By Joel Nonnweiler, Galen Samuelson Nagle

The Sacramento Regional County Sanitation District (SRCSD) has undertaken an interceptor expansion program to meet future wastewater needs associated with projected growth over the next 20 years. The Lower Northwest Interceptor (LNWI) will include over 17 miles (27 kilometers) of pipeline including 14 miles (23 kilometers) of dual force main ranging in size from 54- to 60-inch (137- to 152-centimeter) diameter and 3 miles (5 kilometers) of 120-inch (305-centimeter) diameter gravity pipeline. The estimated capital cost for the program is $331 million, with approximately $236 million in construction cost (as of November 2002). The project includes 4,700 feet (1,433meters) of tunnel including 2 crossings of the Sacramento River and one crossing of the Barge Canal, and 11 other smaller tunnel crossings beneath various creeks, sloughs, highways, and railroads. Preliminary design of the tunnels for the LNWI are discussed in this paper. The overall purpose of the preliminary design was to sufficiently define the project to allow planning level cost and schedule estimates to be performed. There have been changes to the project during final design including pipe sizes and configurations, tunnel and pipeline lengths and anticipated flows. This paper addresses only the preliminary design of the LNWI tunnels. Final design issues and changes made since completion of preliminary design are not addressed in this paper.

Jan 1, 2003

By O. D. Staman

The risk assessment project examines the likelihood of inorganic contaminants from copper dump-leaching operations to contaminate domestic water supplies. The project examines contaminant transport by modeling contaminant movement from the base of a leach pile through the unsaturated zone and into the saturated zone. The modeling effort is unique in that it models infiltration, contaminant transport in the unsaturated and saturated zone combined with geochemical modeling of the unsaturated zone. The project incorporates probability theory to reflect the uncertainty of hydrogeologic parameters.

Jan 1, 1994

By Jeffrey B. Smith

Introduction The gas shortage is going to be with us for some time to come. If we can set aside political and industry rhetoric (along with subjective personal opinions), we still are confronted by two serious "facts of life": (1) for almost a decade the U.S. has been consuming natural gas at a greater rate than we have been finding new reserves; and (2) there is a finite amount of natural gas present within the earth&apos;s crust. Much of the known and easily exploitable sources of gas (the so-called "conventional" sources, such as the high permeability sand reservoirs of the Tertiary sequence along the Gulf Coast) already have been developed; their production is declining rapidly. The total producible reserves from conventional gas reservoirs amount to only 216 Tcf, less than an 11-year supply. However, several large potential resources of natural gas remain to be developed. These "unconventional sources" have low permeability and/or peculiar producing characteristics. The DOE program for development of these unconventional sources of gas is called the enhanced gas recovery (EGR) program. The primary goal of this program is to provide a data base of resource characterization and production technology that will lead to commercial development. DOE will encourage and support industry participation in developing and demonstrating technologies needed to reach this goal. Unconventional Resources Four major unconventional resources of gas have a high potential for commercial development. There are other unconventional sources (such as gas hydrates) that are too poorly defined to warrant a major development thrust at this time. The four unconventional sources of gas currently included in the EGR program are: 1. The carbonaceous shales of Devonian age in the Appalachian, Illinois, and Michigan sedimentary basins are the targets of the Eastern Gas Shales Project (EGSP). 2. The low permeability, low porosity so-called "tight" gas sandstones of the Upper Cretaceous/Lower Tertiary in the Rocky Mountain areas constitute the resource target for the Western Gas Sands Project (WGSP). 3. The free methane trapped in coal beds of both the eastern and western U. S. constitute the Methane from Coal Beds Project (MCBP). 4. The abnormally high pressured, high-temperature saltwater aquifers of the Texas-Louisiana gulf coast are targets of the Geopressured Aquifer Project (GPAP). Basic implementation strategy for these EGR projects involve (1) assessing and characterizing the resource potential of the resource; (2) conducting cost-shared field testing with industry to improve, develop, and demonstrate various stimulation and production technologies; (3) coordinating EGR activities within DOE and with other federal agencies (such as the Bureau of Mines) to minimize duplication; and (4) aiming all projects toward commercial development of the gas resources. EGSP What type of "geological animal" is the EGSP dealing with? While gas undeniably is related to the occurrence of natural fracture systems within the shale, the overall producing mechanism and precise location of fractured, gas-bearing locales within each basin is still poorly understood. By developing reliable resource characterization techniques and applying effective stimulation technologies we intend to elevate the Devonian shale from the status of a potential gas resource to that of a proven gas reserve. Once we have done this the private sector can take over the large-scale commercial development of the Devonian shale gas resource. WGSP The second largest project (both in terms of complexity and level of funding) is the WGSP. The primary targets for this project are the low permeability (< 1 md) gas sandstones of the Piceance, Uintah, and Greater Green River basins and the Northern Great Plains Province. Project success in these four primary geologic locales will permit investigating additional low permeability sandstones in 16 other sedimentary basins. It appears that the only practical means of increasing permeability and resultant flow rates from these sandstones lies in the use of massive hydraulic fracturing techniques. Unfortunately, it is still too early to design such jobs with predictable results. MCBP The MCBP is to be involved in producing and utilizing methane derived from coal beds. The coal, like portions of the Devonian shale, is impermeable, highly fractured (termed "cleat" by

Jan 9, 1980

By R. J. Matetic

The impact of longwall mining on the local hydrological regime has become an important environmental focal point. Unfortunately, only a few studies have addressed the timing and range of well fluid level fluctuations and the associated ground movement. Furthermore, even fewer studies have determined the influence of longwall mining on water quality. The U.S. Bureau of Mines is providing insight into this environmental concern through a program of field case studies. One such study was conducted in Cambria County, PA where five observation water wells were drilled above two adjacent longwall panels. In this study, three wells were completed as nested piezometers and the remaining two served as producing wells. The piezometers were positioned along a line oriented subparallel to the longwall face and were located at the centerline of each panel and over the intervening chain pillars. The piezometers were designed to monitor fluid level fluctuations in both shallow and deep water-bearing zones. Slug tests were conducted before and after mining to characterize changes in hydraulic conductivity of the respective water-bearing zones. Pressure transducers and data loggers were installed to provide continuous fluid level fluctuation data as mining developed through the study area. The producing wells were drilled to provide water quality information. One well was located directly above the centerline of a panel and the other was positioned over the panel&apos;s set-up rooms. The wells were designed to simulate domestic use and were produced daily, for four hour intervals, throughout the study. Samples of the produced water were collected before and after mining progressed through the area. In addition, an array of monuments was installed near the study wells and was periodically surveyed to characterize mining-induced surface deformations. This study shows that: a) the observed changes in ground water chemistry did not affect the potability of the water; b) short-term major water level fluctuations occur at the approximate time of undermining; and c) water level recovery begins before the process of subsidence is complete.

Jan 1, 1986

By J. J. Carlson

Studies were carried out to determine whether filtration rate changes observed in an iron ore concentrator were due to variations in particle shape. It was confirmed that ores mined from different locations differed in filtration rates by as much as 60%. However, when image analysis was used to quantify the shapes of the individual particles in the filtration feed, it was found that the particle shapes showed almost no variation, and the shapes did not correlate with the filtration rate. It was also determined that the filtration rate variations were not caused by changes in particle size distribution. These results suggest that the differences in filtration rate are due to factors other than size and shape, such as surface chemistry.

Jan 1, 2008

By P. A. K. Wilkinson

This paper is concerned with the development of an in situ recovery of boric acid from a deep-seated colemanite deposit in California. The deposit contains 147 million tons of borate ore containing 6.4% boron oxide (B203). It is the largest undeveloped colemanite deposit in the United States and because of its unique occurrence and grade, in situ extraction appears to be the most economic viable process. The paper covers the geological, mineralogical, hydrological, well-field development, and extraction considerations leading to the initial pilot plant and subsequent demonstration plant phases of the project. Market potential aspects and preliminary economics of the project are also covered.

Jan 1, 1987

By M. Sengupta

Surface mining in arctic regions is characterized by many unique problems. Continuous and discontinuous permafrost (perennially frozen ground) occurs in most of the arctic and subarctic areas. Permafrost presents special problems of slope stability. Stability of permafrost depends on its temperature, moisture content and material type. Permafrost slope fails due to solifluction, disturbance of ice rich slopes, and liquefaction. Drilling and blasting of frozen ground present special problems. Depending on their degree of saturation with water, freezing soils and rocks have a number of important characteristics that affect blasting efficiency. Metals used in mining equipment and mining structures require special selection. At low temperatures many steels lose most of their normal ductility and toughness (resistance to brittle fracture). The paper discusses engineering solutions to unique problems of arctic mining.

Jan 1, 1986

By E. Kokinou

The main scope of the present study is to investigate the suitability and sensitivity of the magnetic susceptibility as a pollution monitoring tool in urban areas. For this purpose, a municipal park located in the centre of Chania city, which may be affected by traffic and domestic heating pollution, was selected as the study area. In the context of the present work, magnetic susceptibility measurements were conducted in two phases. Surface soil samples were collected in 2006 from the area under investigation and they were analyzed in order to estimate the spatial distribution of the magnetic susceptibility. One year later, mapping of the magnetic susceptibility has been contacted in situ using Bartington MS2D and MS2F sensors. Additionally, soil samples were collected from selected positions in order to compare the values of the magnetic susceptibility with that estimated in 2006 research. Both investigations indicate high values of the magnetic susceptibility around the park near the roads and in a small area inside the park where a café is located.

Jan 1, 2008

By J. Jeffrey Wagner, Michael J. Bailey, Peter M. Douglass

The Chambers Creek Interceptor Sewer Tunnel project consisted of 2-1/2 miles (4 kilometres) of nominal 9-foot (2.7-metre) O.D. tunnel driven through predominantly glacially overridden soils. Mole-Collucio Construction Company initially elected to drive the entire tunnel with a Lovat TBM. However, this machine could not control the fast raveling ground conditions which developed when the TBM encountered sands overlying very dense, hard glacial till or boulders. As a result, a shield and digger machine was brought in for a 1700-foot (518-metre) long segment. Pumped wells spaced roughly 50 to 125 feet (15 to 38 metres) apart were utilized to dewater about two-thirds of the alignment during construction. Initial support consisted of steel ribs and wood lagging, with a final lining comprised of pre-cast concrete pipe segments grouted in place.

Jan 1, 1985

By Harold Bloom

The Mount Pleasant Mines, or Mount Pleasant Joint Venture as it is presently known, is located approximately 59.5 km (37 miles) south of Fredericton, NB, Canada. Earliest indications of mineralization were found in 1954, during a regional reconnaissance geochemical stream sediment survey carried out over large parts of New Brunswick and the Gaspé Peninsula. The regional geology of New Brunswick is shown in Fig. 1. This program, sponsored by Selco Exploration Co. Ltd. of Toronto was conducted by H. Bloom, H.E. Hawkes, J.E. Riddell, and J.S. Webb. At its conclusion in 1955, 30 significant anomalous drainages were identified for follow-up evaluation. A total of 4937 sample sites were occupied. Geochemical reconnaissance using stream sediment sampling was a new technique which had only been field tested the previous year in the Gaspé and the northern coastal area of New Brunswick. Sediments collected from known mineralized drainages were found to leave a train of anomalous heavy metals from 1.6 to 9.7 km (1 to 6 miles) in length. When the exercise was extended to a reconnaissance survey, the previously unknown mineralized prospect at Nash Creek, New Brunswick, was discovered, staked, and later drilled (Hawkes and Bloom, 1956). Although it did not come into production, the discovery left little doubt as to the viability of the method and led to the Selco sponsorship of the program for the following two years.

Jan 1, 1991

By Djavid Mohammad

Over the next several years, the storage capacity of the Metropolitan Water Reclamation District of Greater Chicago?s Tunnel and Reservoir Plan will be increased by 14.8 billion gallons through the addition of two large off-line reservoirs: the McCook and Thornton Reservoirs. The Thornton Reservoir will be constructed at the terminus of Calumet TARP System. The constructed TARP system will be connected to the Thornton Reservoir via connecting tunnels and gates systems. The connecting tunnels will comprise of: an upgradient transition tunnel, steel lined bifurcated tunnel for conveyance and control of flow, downdradient transition tunnel, and energy diffuser at tunnel portal. A large, approximately 250-foot-long, 69-foot-wide, and 40-foot-high, rock cavern will be excavated at an average depth of 320 feet to house the bifurcated tunnel system and associated six large control gates, each 12.5-ft by 28-ft wheel gate. Presented in this article are discussions about the TARP system, the Connecting Tunnels and gates Project, regional rock conditions, evaluation of reservoir?s wall stability for evaluation of tunnel penetration, and design challenges facing during design of the: rock cavern hosting the bifurcated tunnel system and gates and associated tunnels and shaft.

Jan 1, 2008

By W. A. Lawruk, L. J. Wilson, D. E. Stief

The Tower mill is a vertical stirred mill using steel balls or pebble grinding media. This device is designed for fine grinding at significant power savings when compared to conventional tumbling mills. This paper describes the machine and its operation, application, and performance for wet grinding.

Jan 1, 1988

By Thomas F. Martin, Daniel J. Sieve

In April 1988, the joint venture of Morrison-Knudsen and Paschen Contractors (M-K/P) was the successful low bidder for the Metropolitan Water Reclamation District of Greater Chicago&apos;s (MWRD) Contract Number 73-164-2H. This project is yet another in the MWRD Tunnel and Reservoir Plan (TARP) devised to control and treat overflows from combined sanitary and stormwater flows. M-K/P&apos;s project, located along the Des Plaines River, consists of 21,569&apos; of tunnel mined to a 35&apos; diameter and two tunnels totaling 14,529&apos; mined to a 12&apos; diameter. All three tunnels will have 12" thick reinforced concrete lining. The path for combined sewer/storm waters to reach the tunnels begins at a connection structure, continues through an approach sewer, a sluice gate structure and down a vertical shaft which is topped by a backflow structure. The purpose of the backflow structure is to prevent water surging to the surface as the system fills rapidly. Backflow preventors represent a change in design after problems developed on earlier constructed portions of the T.A.R.P.. On this project, 14 drop shafts channel flows to the tunnel system. In addition to the drop shafts, contract specifications require an emergency or escape shaft be located not more than 4000 feet from the tunnel headings. Due to long reaches without drop shafts, four access shafts had to be constructed. Thus, the total shafts constructed under this contract will be eighteen plus one 30&apos; finished diameter construction shaft located within Miller&apos;s Meadows. Figure 1 shows the overall Des Plaines River System and the M-K/P contract connection to previous and future MWRD projects.

Jan 1, 1991

The design of solvent extraction plants has been generally based on the assumption of steady operating conditions in both the settler and the mixer units. However, recent experience in both large and small plants has shown this not to be the case. Mixer transients include start up aqueous locking and partial phase separation in secondary mixers, which both lead to reduced plant capacity or overflow of upstream mixers. Analysis of the hydraulic pressure profiles has generated new design methods to eliminate the effects of the partial or complete phase separation. Changes to the method of specification and selection of primary and secondary mixers have been made to eliminate the onset of partial separation during operation. The observation of settler operation has shown that it is also a dynamic process, even under "steady-state" conditions. Four transient phenomena have been identified that lead to internal circulating flows, poor disengagement of fine secondary haze and erratic and high entrainment levels in the discharges. A, first approximation analysis has shown that there are significant pressure differentials within settlers, and these change along the length and with the phase separation rates. A technique to control the effects of these transients was developed that allows plant performance to be improved beyond "standard" expectations. The design and selection of the settler internals is described. Key words: Solvent extraction, Mixer-settlers, Phase separation, Entrainment, Mixer transients

Jan 1, 2003

By R. W. Barbaro, R. V. Ramani

Generally, production planning is concerned with the best use of fixed resources to determine a production schedule for one or more production units supplying one or more markets. Production scheduling determines when each production unit will be used and its production level. However, the production scheduling problems are intimately associated with the location of existing or new production units and processing facilities. Normally, mine location allows only a limited choice; processing plant types and locations are considerably more flexible. This paper presents a generalized multiperiod MIP model as an aid in determining the mine production schedule and the processing plant types and location to satisfy multiple markets. A brief description of MIP and how it has been applied in the mineral and other industries is discussed. A complete description of the model with an application to a coal preparation plant system is presented.

Jan 1, 1987

An open pit production planning method for stage mining is presented in this paper. The method brings solutions to the four most important parameters in stage mining : 1) the number of stages, 2) the size and geometry of each stage pit, 3) the mining sequence of the benches in the stage pits, and 4) the time of transition from one stage to the next. The method can also simultaneously optimize the ultimate pit, mine life, and production rate in each stage.

Jan 1, 1996

By K. Short

Today?s modern mining operations have literally dozens of applications and systems generating data whose information very often, are not crossed or centralized for operational decisions. In remote locations, the information and situation awareness is typically limited to the location itself. In addition, access to that information is limited to a small, select group of personnel that have received training on how to interpret the results. When the situation affects another area of the mine then information is relayed to the applicable areas involved. Few workers have time to analyze the situation thoroughly, to see how it affects the mines symbiotic relationship within all areas of production. If the capability to correlate and measure events and situations that affect your overall key performance indicators are not in place, the opportunity to identify process improvement becomes more difficult.

Feb 27, 2013