Search Documents

By Diana K. Schimmelpfennig

Assessment of revegetation success on mined lands is a difficult, time consuming task and has been the subject of a number of controversies. Present regulations require that both plant cover and aboveground plant biomass be measured for use in making that assessment. Of these two variables, biomass is the most time consuming to measure and requires destructive sampling, a most undesirable requirement on fragile, recently revegetated areas. On the other hand, plant cover can be estimated using the point-frame method which is relatively nondestructive. In addition, vegetation can be sampled more uniformly with the point frame and in less time if species composition measures are to be made. A study was done to evaluate the predictability of aboveground biomass production on revegetated mined sites and adjacent native prairies using plant cover estimates made with the point frame method. The predictability of biomass production by cover estimates bears on the need for both measurements in assessing revegetation success. In general, a positive, statistically, significant correlation was demonstrated between plant cover (estimated by the point frame) and aboveground biomass (estimated by the harvest method) regardless of community type (mined or native), species composition, diversity or level of biomass production. However, the latter did have their effects on the relationship and must be accounted for in any predictive equations (that is to say, the predictive equations must be considered site-specific). Considering the relationship observed between the two parameters, cover estimation may be a sufficient indicator of revegetation success, especially where time and minimization of disturbance are critical.

Jan 1, 1982

By Donlad B. Lindsay

This report describes a field-test program to determine the effectiveness of a polymeric wall sealant to reduce the excape of naturally occurring radio-active gas radon from the walls of an underground uranium mine into the ventilation air. A 75-foot-long, dead-end drift with a surface area of about 6,000 ft2 was used as the test site in which the average natural radon flux from the normally dry rock was 16 fCi/cm2-s. The effect on radon emanation of wetting the walls with water to a depth of 3 inches was tested, after which the rock was completely covered with a coating of dry-mix concrete to provide a base for the sealant, an acrylic latex. Sealant was applied in two coats to about 0.25 mm thick. An overall reduction of average radon flux of about 75 pct was achieved. Radon production and other environmental values were measured continuously and automatically by a Bureau of Mines data acquisition system. A commercial microcomputer was programed to convert raw data to engineering units and to perform other useful operations while recording all data on magnetic diskettes. Direct measurements of radon flux from the rock surface were made by a charcoal adsorption technique.

Jan 1, 1981

By J Joy, D Griffiths, A Bye, G V. Kizil

Poor standards of electrical installation and maintenance continue to contribute to electrical related fatalities and injury risk in the mining industry. Electrical isolation has the potential to initiate major unwanted events (MUEs) and as such requires thorough analysis to demonstrate adequate management. There have been 719 incidents related to accidental contact with electricity over the past five years in the Queensland mining industry (Queensland Government DME, 2012a, 2012b) with the last fatality being recorded in 1997 (MESA, 2012).A project funded by the Australian Coal Association Research Program (ACARP) has developed a form of a safety case using the four-layered æCoal Mine Safety Regime (CMSR)Æ approach. The CMSR is transparent and robust as it includes full site risk assessment and special issues risk assessment to be demonstrated as part of the process.The practical application of the CMSR has been demonstrated using a longwall mining case study site, where a unique 11 kV armoured face conveyor (AFC) is in operation. The case study has involved progressive application of the requirements of each layer of the CMSR (see Figure 1) to high voltage (HV) electrical isolation related issues. The project has specifically concentrated on understanding and analysing two high priority MUEs, electric shock and unplanned movement of equipment, through Layer 1 analysis. These two MUEs are an important part of the project as they have demonstrated the steps that may be taken to satisfy the risk management processes at Layer 1 of the CMSR and have contributed to resolving issues at the other three layers of the CMSR.The analysis of HV electrical isolation has been used as an exemplar to demonstrate the CMSR process and its practical application. The CMSR is applicable to major/principal hazards management as identified by the New South Wales and Queensland jurisdictions.This paper provides an overview of the development of a form of safety case using the CMSR and introduces the case study application for HV electrical isolation risk management at underground coal mines focusing on the major unwanted event of electric shock.This project provides the mining industry with a documented, publicly accessible, form of safety case using the CMSR approach for the first time.CITATION:Kizil, G V, Griffiths, D, Bye, A and Joy, J, 2012. Using a coal mine safety regime approach to the management of high-voltage electrical isolation, in Proceedings International Mine Management 2012, pp 59-74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Romano J. Micciche

One of the largest scale uses of a multiple, high-strength steel bar tiedown system is described. Tiedowns were installed to resist hydrostatic uplift forces acting on a section of the Interstate Highway Route I-90 southern approach roadway to the Third Harbor Tunnel, in Boston, Massachusetts. Site specific information is discussed regarding design, testing, and installation of Tiedowns. Conclusions are presented regarding the overall performance of this system and the application of this type of tiedown system on future projects.

Jan 1, 1994

By Charles J. Stehlik

This report deals with the changing behavior of mine roof bolt and roof rock as a result of repetitious production blasting . Observations were made in the upper shale production headings at the White Pine Copper Co. room and pillar mine , White Pine , Mich . Roof bolt compression pads and a stratascope were used in the investigations , which were carried out in three separate test sites in which nearly identical procedure produced comparative , repetitive , and anomalous observations . Results indicate roof bolt tension change and roof quality deterioration anomalies were coincident with blasting . The hypothesized cause of the anomalies is a seismic shock generated by the blasts .

Jan 1, 1964

By Yvette Heritage

"The risk of fatalities from rib failure is still prevalent in the coal mining industry. This risk has prompted further research to be conducted on rib deformation in order to understand the mechanisms of rib failure, with the long-term objective being to improve rib support design. This paper presents the results of ACARP research project C25057, which investigated the mechanics and drivers of rib failure. The results of rib deformation monitoring at three different mines in Australia provides rib deformation characteristics for overburden depths ranging from 160 m to 530 m. Monitoring includes deformation during development drivage conditions and during the longwall retreat abutment stress environment. The rib deformation monitoring covered three different seams: the Goonyella Middle Seam, Ulan Seam, and Bulli Seam in the Bowen Basin, Western Coalfield, and Southern Coalfield, respectively. The observed mechanisms driving the rib deformation ranged from bedding shear failure along weak claystone bands to vertical shear fractures to kinematic failures driven by shear failure dilation. The variation in mechanisms of rib failure, together with the seemingly consistent method of rib support design, prompts the question: What exactly is the role of rib support?INTRODUCTIONThe current risk of rib fatalities in the coal mining industry has prompted further research into understanding the mechanisms of rib failure. Three Australian mines assisted further research by providing sites for rib deformation studies as part of the Australian Coal Association Research Program (ACARP) project C25057. The mines included in this study were Moranbah North Mine, Ulan West Mine, and Appin Mine. This paper provides key results of the rib deformation monitoring relevant to assessing the mechanisms of rib deformation.The approach of monitoring rib deformation and rib support loads was used to measure and characterise the dynamic rib deformation present in both development and longwall retreat stress environments. The characterisation of rib deformation, together with rock failure modelling, was used to determine the mechanisms for failure within the rib and to assess the interaction of rib support with the failure process. The mechanisms of rock failure are considered an important factor in understanding the drivers for the failure. Consideration of the site-specific failure mechanisms can provide for a more tailored support design."

Jan 1, 2018

By K G. Harding, A Osman, A du Toit, F K. Crundwell, C M. Sheridan

"Most mineral processing plants have high water requirements for their operational activities. These plants often function in an environment where water is becoming increasingly scarce. An increase in population will result in an increased demand for water; potentially beyond the limits of supply and hence increased competition for the resource. In South Africa, Gauteng and the North West Province are likely to be first to experience a shortage of potable water.In order to avoid a water crisis, efforts must be made to ensure the effective management of water resources and the minimisation of wastage. Hydrometallurgical plants have a responsibility to society and the environment to operate in a sustainable manner - reducing their water requirements will certainly assist towards developing a sustainable footprint.This project improved site water management by: surveying the potable water and storm water systems with a view to assessing the current water accountability and determining methods to improve accountability determining the monthly and yearly water balance for the site and presenting it in the form of a water balance sheet drawing up an input-output and operational model in accordance with the Minerals Council of AustraliaÆs æWater Accounting Framework for the Minerals IndustryÆ calculating the water footprints of the refinery identifying ways in which water savings could be achieved recommending management systems for water usage monitoring.This work was conducted in South Africa. The value of this work lies in that it established the current baseline and assisted in developing management systems that can reduce water usage sustainably.CITATION:Osman, A, Crundwell, F K, Harding, K G, Sheridan, C M and du Toit, A, 2013. Water accountability and efficiency at a base metals refinery, in Proceedings Water in Mining 2013, pp 277-286 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By D. R. Willmer, E. J. Haas

As national and international health and safety management system (HSMS) standards are voluntarily accepted or regulated into practice, organizations are making an effort to modify and integrate strategic elements of a connected management system into their daily risk management practices. In high-risk industries such as mining, that effort takes on added importance. The mining industry has long recognized the importance of a more integrated approach to recognizing and responding to sitespecific risks, encouraging the adoption of a risk-based management framework. Recently, the U.S. National Mining Association led the development of an industry-specific HSMS built on the strategic frameworks of ANSI: Z10, OHSAS 18001, The American Chemistry Council’s Responsible Care, and ILO-OSH 2001. All of these standards provide strategic guidance and focus on how to incorporate a plan-do-check-act cycle into the identification, management and evaluation of worksite risks. This paper details an exploratory study into whether practices associated with executing a risk-based management framework are visible through the actions of an organization’s site-level management of health and safety risks. The results of this study show ways that site-level leaders manage day-to-day risk at their operations that can be characterized according to practices associated with a risk-based management framework. Having tangible operational examples of day-to-day risk management can serve as a starting point for evaluating field-level risk assessment efforts and their alignment to overall company efforts at effective risk mitigation through a HSMS or other processes.

Jan 1, 2016

"A commercially available Through-the-Earth (TTE) communications system was evaluated at an active underground longwall mine in West Virginia. This TTE system uses electric field (E-field) sensing to send text based communications using two separate antenna arrays connected in parallel. Each antenna array is composed of interconnected, grounded metallic rods or other such structures. Two-way communication between subsurface locations was investigated in this study using various antenna configurations. This field study was conducted as a part of a larger multi-site evaluation of available TTE systems in an effort to determine their operational sensitivity. INTRODUCTION Wireless, Through-the-Earth (TTE) communication technology is designed to achieve point to point communication through solid strata using very low frequency (VLF) and ultra-low frequency (ULF) electromagnetic waves. This ability allows TTE communication to function without the need for intermediary communications infrastructure, such as repeaters. As a result, such communication systems have the potential to provide reliable, robust communications between surface and underground personnel. Exploration into the use of TTE technology for this purpose dates back to the 1920s (Jakosky and Zellers 1924; Pittman, Church and McLendon 1985), but U.S. permissibility requirements slowed the development of TTE equipment for widespread implementation (Durkin 1980; Pittman, Church and McLendon 1985). One of the primary challenges in producing wireless TTE communications is the counteraction of signal attenuation when propagating through solid strata (Barkand, Damiano and Shumaker 2006; Wadley 1949). The long wavelengths of TTE transmissions make them well-suited for reducing the rate of attenuation. However, even when operating within the VLF to ULF range, the performance of TTE systems is still affected by geologic and anthropogenic factors (Geyer 1973; Geyer and Keller 1976; Geyer, Keller and Ohya 1974; Jakosky and Zellers 1924; Large, Ball and Farstad 1973). Although commercially developed TTE systems have demonstrated the ability to communicate through a variety of conditions, their range and performance have been highly varied (Barkand, Damiano and Shumaker 2006; Geyer and Keller 1976; Geyer, Keller and Ohya 1974; Ilsley, Freeman and Zellers 1928; Jakosky and Zellers 1924; Yenchek et al. 2012)."

Jan 1, 2016

By George J. Tamaro

The design and construction of foundations in the New York City area are usually dictated by the widely varying geologic conditions encountered in the five boroughs, particularly along the spine of Manhattan Island. Rock extends well above sea level at the northern reaches and falls to depths in excess of 250 m at the barrier islands at the southern extremities. These highly variable geologic conditions, significantly affected by glacial activity, dictate different design and construction approaches throughout the five boroughs of New York City. Extensive rock removal is required at the north while long piling is dictated in the south. Similar changes can occur within a project site on Manhattan Island. This paper will describe these conditions in general, will identify the various solutions used to solve these problems and will summarize various foundation types used in the New York City area.

Jan 1, 2000

By Michael J. Beus

This Bureau of Mines report describes field investigations conducted in the Coeur d'Alene mining district of Idaho to obtain data on rock stress and physical properties. The resulting information has been utilized as input to detailed finite-element analyses to establish structural design criteria for deep-vein mine shafts. Measurement techniques include the Council for Scientific and Industrial Research biaxial and triaxial strain cells, the U.S. Geological Survey solid-inclusion probe, and the Colorado School of Mines dilatometer. Physical property testing was conducted in the laboratory on core obtained from each test site. Limited in situ physical property tests were also conducted. Reason-able success was obtained with the CSIR equipment, which was considered the most suitable for stress measurement in the study area. Test sites ranged in depth from 1,200 to 7,700 feet and are described in detail. The stress data were reduced by least-squares linear regression techniques to enable prediction of vertical and horizontal stresses to 7,500 feet. Ratios between the horizontal stresses as utilized for shaft design varied considerably, and a hydrostatic condition is the exception, based on Bureau measurements. Physical properties also varied widely, due to the complex geologic structure. Analyses of the data in terms of the tectonic history of the area show reasonable correlation. Data from previous rock mechanics investigations from the Coeur d'Alene district were also compiled and presented as part of this report to justify any generalizations regarding stress conditions and physical properties of the district as a whole.

Jan 1, 1980

By K. E. Robinson

This study provides an initial indication that mill tailings produced in the Coeur d'Alene Mining District of Idaho can be placed on floodplain areas in a technically acceptable manner without artificial liners and without seriously contaminating the surrounding area. Tests have shown that landfills on these unused areas can result in returning these areas to productive use. The engineering properties of mill tailings permit construction of stable embankments. Designed slope protection inhibits water erosion. Among the environmental considerations in using tailings for landfill construction are the acid and other contamination produced by tailings and wind erosion of exposed tailings surfaces. The initial results indicate that adverse impacts are not as severe as previously thought, and mitigative measures are feasible. Based on the preliminary data, and in accord with existing Federal and State waste management regulations, a conceptual design has been developed for 23 potential landfill sites in the District, which could reclaim 750 acres of floodplain. A cost analysis of landfill construction with mill tailings indicates that the method would be an economically viable means for increasing the valleywide tailings storage capacity, provided construction with slurried tailings is feasible. A Stage H study is proposed to evaluate slurried tailings as a foundation material, as opposed to hauled tailings used in this present study.

Jan 1, 1981

By Owen F. Jensen

CONSTRUCTION of a ground-water supply includes many operations, which do not end with completion of facilities. Evaluations must be made of the quality of water in various areas and the history of production. Following an analysis of geologic, hydrologic, and chemical data there must be an exploratory drilling program and a study of resulting information. When the well is completed a continuous survey of operating records and basic data is necessary, since designs for future wells are varied as more data becomes available for those already completed. As the following discussion must be limited to a single undertaking, the customary procedure will be outlined for development and construction of a ground-water supply in which more than three wells are involved. Parts of this procedure are applicable for all ground-water supplies. Three possible sites were selected for construction of a paper mill. The problem was that the industry daily required approximately 15 million gallons of water of the best quality available; however, if water of the best quality were not available in the desired amount, water of a poorer quality could be used up to half the required amount, about 7 million gallons. In the preliminary survey approximately 1500 to 2000 square miles were covered for each site. Collected data consisted of several hundred electric logs of oil and gas wells; reports by the U. S. Geological Survey on ground-water resources of localities in and near the area; unpublished records of several hundred water wells including chemical analyses of the water produced and drillers' logs of the wells; records of periodic water-level measurements made in observation wells by the USGS; topographic maps drawn up by USGS and by army engineers; and highway and county road maps. A preliminary report based on study and evaluation of these data was presented to the client, recommending the site with the most favorable and economical ground-water conditions. The study indicated that water of the quality and quantity desired could be developed. In this particular area there were indications that the aquifer could be separated into two zones con- taining water of different chemical character. This chemical character varied somewhat with area, but principally with depth, a factor which later proved an economic advantage in design of the well field. After studying the preliminary report, the client weighed other economic factors as well as ground-water advantages and selected a plant site. Authority was given to proceed with detailed study of the chosen area. Evaluation of preliminary data concerning the area indicated that it should be supplemented with additional information derived from actual exploratory drilling and testing. A flexible plan of exploratory drilling was devised so that data obtained as each test hole was drilled could be correlated with existing data and additional test holes could be located and drilled accordingly. Specific data to be obtained from each test hole were: samples of all formations penetrated; the driller's descriptive log of formations; electric logging surveys; one or more samples of water from selected water-bearing formations; temperature; and water levels and their recovery after periods of production. The area studied in such detail was approximately 400 square miles. Choice of location for the original test holes was based on the preliminary study. The pattern for these test holes was designed to require a minimum number of holes and to allow for interpolation of data between two, three, and four holes. Geologic, hydrologic, and chemical data gathered after completion of the first four test holes showed that the north section was the most desirable in the area, which was then reduced from the original 400 square miles to about 150 square miles for more detailed and intensive study. On the basis of findings from the current test a tentative well field was laid out and a drilling program devised. One test hole was located on the actual plant site and later developed into a small pilot production well equipped with a deep well turbine pump. Water from this well was used for general construction requirements. Another test hole drilled near the pilot production well and adjacent to the proposed route of the well-collection system was used during the pumping test of the pilot production well to determine the degree of interference. From the data thus obtained, calculations were made to determine the coefficients of transmissibility and storage. Three additional holes

Jan 1, 1955

By R. G. Treuting, W. C. Ellis

The twinned state is characterized by a lattice of coincidence sites. Imperfections are required at stable lateral twin interfaces. Twinned regions can occur with relative ease in the diamond cubic IN recent contributions1,2 on the origin and growth of cubic annealing twins, attention has been directed to the orientation relations between such twinned components and their parent matrix. There are some aspects of twinning which may be illuminated by a more detailed consideration of the twinned state" alone. As an extreme example, the dense twinning in cast ingots of germanium,&apos; as contrasted with the rarity of twins in cast face-centered cubic metals, is yet to be accounted for. It has been this that has led us to the present work, which, it will be noted, uses methods and constructions in many respects similar to those of Kronberg and Wilson.&apos; In the cubic systems, a 70" 32&apos; rotation about a <110> axis is angularly equivalent, as to twinning, to the more usually considered 180" rotation about a <111> axis. Figs. 1 and 2 show a (110) projection of a twinned face-centered cubic lattice and a twinned diamond cubic lattice. In both figures, the two adjacent planes A and B, shown by the larger and smaller circles, are sufficient to represent the entire array. In each case a section of lattice, the original atom sites of which are shown by open circles, has been rotated as indicated through 70" 32&apos; to bring an original. [112] direction into coincidence with the [112] diiection. The latter is the intercept on the (110) projection of the (ill) plane normal thereto, the twinning plane. In the face-centered cubic case the rotation can be performed about an axis passing through an atom-site; the mirror plane then is also a composition plane containing atoms common to both twinned and untwinned lattices. The diamond cubic lattice may be construed as two interpenetrated face-centered lattices. Its (111) planes recur in a sequence of alternately short and long interspacings. Consequently a mirror plane for twinning cannot be a composition plane, but must be the bisector of one of the spacings. When the longer spacing is selected, the closest distance of approach across the mirror plane in the [ill] direc- tion is identical with that in the untwinned structure. In each case periodically recurring (ill) planes (parallel with the twinning plane) are found, on which there is coincidence of atom sites of the pre-twinned and twinned orientations; these are indicated by the cross-hatched circles. In the face-centered lattice there is such coincidence every third (ill) plane; in the diamond cubic lattice, on two adjacent planes in every six. At the twinning interface in the latter, there is on each side of the mirror plane a (ill) plane of atoms common to both twin components. Conceivably, there is little influence on a plane of atoms about to be adhered to such a pair of coincidence planes, whether it be laid down in a normal or in a twinned position with respect to the previously formed structure. Slawson% as attributed the high incidence of twinning in diamond to this boundary state. Further examination shows that the motion of intermediate planes can consist of various pairs of equal and opposite translations, for example of (ill) planes in the [l&apos;;i2) direction, the familiar twinning shear, indicated in the small schematics in the figures. Since the translations form a system of shears of alternating sign between coincidence planes, twinning could take place by such a mechanism over an extended region without extensive shear; in fact, in this case any atom moves but the distance in the [1i2] direction. One alternative construction for the face-centered cubic lattice leading to the same end result is illustrated in Fig. 3. The plane (711) with respect to the pretwinning orientation (the twinning plane of Fig. 1) is given, the twinned region arbitrarily bounded by <110> and <112> directions. The coupled shear is identical to that of Fig. 1. The "rotational" movement about coincidence sites generating the same twinned position could consist as shown of the translation a,/d% for each atom of a group of three in the B layer in a different one of the three <112> directions, and a similar translation of the underlying three atoms in the C layer in either the same or the opposite sense. This is not dissimilar to Kronberg and Wilson&apos;s construction for their 22" rotation of three adjacent (111) planes.

Jan 1, 1952

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&apos;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 W. R. Deeths

The Great Plains Coal Gasification Project is the first commercial scale grass roots synthetic fuels (SNG) plant to be built in the United States. The plant will be constructed in two phases, with each phase producing 125 million cubic feet per day of pipeline quality (970 BTU per cubic foot) substitute natural gas from lignite coal. The plant is located north of Beulah in Mercer County, North Dakota. The first phase complex, when completed, will cost about 1.2 billion dollars and will include all necessary process units, oxygen production, steam generation, coal handling and preparation, utilities and infrastructure. The plant will be owned and operated by, the Great Plains Coal Gasification Associates, a partnership consisting of the following companies: ANG Coal Gasification Company, Mid Con Corporation, Tenneco, Inc., Transco Energy Company and Pacific Lighting Co. The Project began in late 1973 with a Phase I feasibility study and site selection study. The feasibility study was completed in 1975, at which time Kaiser Engineers and C. E. Lummus, the two engineering contractors, proceeded with a Phase II conceptual engineering design for the project. The culmination of the Phase II work was the publication of a detailed scope definition and control estimate, which was to become the cost guideline for procurement and plant construction. Following an engineering slowdown period in 1979, due to continuing delays in regulatory procedures, detailed engineering effort was reinstituted in early 1980 and by mid-1981 was approximately 35 percent complete. The total home office engineering effort amounts to approximately 3.5 million man hours of work split between Kaiser Engineers and Lummus. These totals exclude the engineering effort expended by Lurgi of Germany in the process design. The gasification plant shares the site and certain other facilities with the Basin Electric Power Station. Among these facilities are the plant access railroad, peripheral drainage ditch and raw water supply system. In addition, the gasification plant will draw its power directly from the Basin main substation, and Basin will receive coal from the gasification plant, consisting of the coal fines which cannot be gasified in the Lurgi units. The overall construction program covers a period of approximately 44 months with mechanical completion and initial gas production slated for late 1984. Craft labor requirements amount to approximately 11.5 million man hours and the work force peaked in excess of 4,500 people. In anticipation of an early resolution of both Federal Energy Regulatory Commission ruling and Department of Energy loan guarantee commitments, certain work on the site was commenced during 1980. This work consisted of site rough grading, driving of piles, and erection of three of the plant auxilliary buildings. Orders and subcontracts were placed for compressors, pumps, electrical equipment, material handling equipment, piping, structural steel, boilers, oxygen plant and cooling towers. Over 40 major Federal, State and local permits were required. Among these were such diverse permits as: ? Soil conservation ?Railroad and pipeline rights of way ? Certificates of site compatibility ? Permits for structures in areas controlled by the ? U.S. Army Corps of Engineers ? Environmental permits required by the North ? Dakota Department of Public Health. The preparation of an Environmental Impact Report began in September of 1973. FPC (now FERC) guidelines and North Dakota special requirements were followed except that, at the time, the highly structured form of environmental impact statements we know today was not in use. We were required to develop a number of new sampling and evaluation techniques and reporting procedures at a time when the requirements were vague and often contradictory. In March 1975, field studies were completed and submitted to the Bureau of Recla¬mation, which then began to prepare its own EIS. Two years later, in May 1977, public hearings began on the Project. The hearings and public review of the report drew over 400 comments or questions. Responses o the comments were in¬corporated in a Final Environmental Impact Statement issued in January 1978. In March 1975, the original filing was made for an FPC Certificate of Public Convenience and Necessity which included: ? A technical feasibility study ? An Environmental Impact Assessment ? An Economic and financial feasibility assessment. An amended filing was submitted in 1976 to build the plant in two phases because studies then indicated that the cost of the plant had increased substantially. A second amended filing was submitted in 1977 to reflect the involvement of Peoples Gas (now Mid-Con Corporation) in the Project. At the time, it was believed that an FPC Certificate could be issued by December 1977. However, approval would be contingent on the U.S. Bureau of Reclamation having a complete Final Environmental Impact Statement for the Project. In 1977, with the formation of the Department of Energy, the FPC

Jan 1, 1984

By Raymond C. Boettner

The present work had for its purpose: 1) the identification of crack nucleation sites in AISI 4340, quenched to martensite and tempered over a range of &apos;temperatures; and 2) the comparison of fatigue processes in AISI 4340 with processes observed previously in pure metals From constant def1ection-bending fatigue tests, martensite boundaries were identified as the favored crack nucleation sites in quenched and tempered AISI 4340. It, also, was concluded that the fatigue processes operating- in this lous-alloy steel were similar to Processes observed in pure tnetals. ALTHOUGH much engineering data has been accumulated on the fatigue properties of quenched and tempered martensitic steels,&apos; fatigue as a process is not as well understood in martensite as it is in pure metals.&apos; Important features of the fatigue process, such as the identity of the nucleation sites, have not been determined in the commercially important high-strength low-alloy structural steels. The present work had for its purpose: 1) the identification of crack nucleation sites in a low-alloy steel, i.e., AISI 4340, which had been quenched to martensite and tempered over a range of temperatures; and 2) the comparison of fatigue processes in the AISI 4340 with processes observed previously in pure metals. This comparison of the fatigue processes in the different tempers was restricted to the high-strain low-cycle part of the S-N curve. Under these test conditions, previous work on a number of metals has shown that a large number of cracks are nucleated in less than 30 pct of the fatigue life.3 Furthermore, crack nucleation sites are not restricted to inclusions but are also associated with intrinsic structural characteristics of the metal. MATERIAL A 20-lb ingot of vacuum-melted AISI 4340 (for composition see Table I) was hot-rolled to 1-in.-diam rod and then cold-rolled to a 1-in.-wide strip, 0.08 in. thick. Fatigue specimens, see insert of Fig. 1, were machined from the strip with the long dimension parallel to the rolling direction. m this orientation, the stringers of 1 to 2 p inclusions present in the sheet lay parallel to the stress axis in the specimens. The specimens were austenitited at 2050°F in order to obtain a large prior austenite grain size, i.e., 2 mm, which facilitated the subsequent identification of the prior austenite boundaries. A helium atmosphere was used to minimize decarburization. After austenitiza-tion at 2050°F, the specimens were transferred to a 1450°F furnace so that specimen distortion was held to a minimum in the subsequent oil quench. Previous work4 indicated that refrigeration in liquid nitrogen prior to tempering reduced the percentage of retained austenite in the quenched specimens to less than 5 pct. Tempering was carried out in air over the temperature interval of 200°to 800°F to produce a range of mechanical properties, Table I. The preparation of the fatigue specimen was completed by grinding about 0.005 in. from each surface and electropolishing in a chrome trioxide-acetic acid solution for 30 min. Examination of etched cross sections of specimens prepared in this fashion showed the foregoing specimen preparation to be adequate for the removal of the decarburized layer present after the heat treatment. Transmission electron microscopy showed that the as-quenched microstructure of this alloy consisted of a mixture of martensite plates containing either a high density of dislocations or microtwins. Previous work5&apos;6 indicated that in the course of oil quenching autotem-pering resulted in the formation of E carbide on the martensite and microtwin boundaries. Tempering for 2 hr at temperatures up to about 400°F resulted in further precipitation of the E carbide. Finally, at about 400°F, cementite began to replace the E carbide on the martensite and microtwin boundaries in addition to forming a Widmanstatten structure within the plate matrix. EXPERIMENTAL S-N curves were obtained using electropolished specimens cycled at 1800 cpm as cantilever beams in fully reversed bending at selected constant deflections. The deflections were translated into surface strains by means of a calibration curve obtained through the use of strain gages. An argon atmosphere was used to minimize environmental effects. To investigate the development of fatigue slip bands, the specimens of the different tempers were unidirec-tionally bent to a surface strain of 0.005 to 0.007, photographed to record the location and appearance of slip bands so introduced, and then cycled to failure

Jan 1, 1968

By H. J. Hutson

BRS, Inc. has utilized Carlson&apos;s Natural RegradeTM software to design the reclamation and stabilization of abandoned open pit uranium mine spoils, AML Project 16N, located in the Gas Hills Uranium District in central Wyoming. This work was completed for the State of Wyoming&apos;s Abandoned Mine Land Program (AML) on preSMCRA (Surface Mining Reclamation and Control Act) sites for which no reclamation obligation existed. The project successfully stabilized an eroding spoil dump, enhanced the local view shed, created habitat diversity and provided a significant source of fill material for open pit highwall hazard mitigation efforts. Additionally, the project served to evaluate innovative reclamation design methods, engineering software and grade control technology. This project was nominated for a National Association of Abandoned Mine Land Programs award by the State of Wyoming. The results of this project will be presented as a case history of the Natural RegradeTM approach to surface mine reclamation. Based on the successful application of this new mine reclamation technology on the AML 16N Project, reclamation designs for spoils associated with planned underground uranium mine operations at the Velvet Mine in the Lisbon Valley Uranium District of Utah for Uranium One USA, Inc have been prepared and will be presented. Critical elements will be the encapsulation of unsuitable materials, long term hydrologic stability, and sequencing and staging of ore and mine waste for final reclamation surface construction. The goal of the Uranium One Velvet Project will be to apply best available technology to reclamation planning and fully integrate the reclamation design with the mine planning. Benefits of the approach should include improved public and regulatory perception of the project, facilitate mine permit approvals and the eventual timely release of reclamation bonds, as it is anticipated the stable landform created through this process will result in more rapid stabilization of the site to pre-mine geomorphic conditions. NATURAL REGRADETM CASE STUDY AML Project 16N, D-9 and K Pit Reclamation Project, is located in an intensely disturbed area of the West Gas Hills Uranium Mining District in Fremont County, Wyoming. The overall design calls for the placement of approximately 7 million cubic yards of backfill materials in the D9 and K Pits, imported from adjacent mine spoils including the Central Spoils, and from local highwall excavation. Figure 1 shows the location of the Central Spoils excavation area, as well as the D9 and K Pits fill area. The entire project is located on public lands administered by the Bureau of Land Management, Lander, Wyoming District Office. No access controls are in place at the abandoned mine sites. The public lands are administered under a multiple use land policy including grazing of range land, public recreation, active mining and exploration, and oil and gas. The project site is located along Fremont County Road No. 5, which is a moderately well traveled road. Reclamation of the numerous and large abandoned open pits in the Gas Hills Uranium District has reduced the risk of death or injury to the public. Site History and Background The Gas Hills Uranium District was mined by multiple companies during the period from 1955 to 1981. The uranium was hosted in the Wind River formation, a sequence of soft sedimentary layers of interbedded sandstone, clayey shales, and conglomerates. Uranium was precipitated out of ground water in classic roll front deposits, which are found from very near surface to depths greater than 400 feet. Prior to the enactment of the Surface Mining Control and Reclamation Act of 1977 (SMCRA), very little reclamation work was performed when mines were abandoned or closed. The State of Wyoming Abandoned Mine Lands Program has worked to mitigate hazards associated with large open pits, control migration of unsuitable materials and restore watershed functionality of lands in the district. Additional reclamation is being performed by mining companies on bonded lands. Figure 2, Gas Hills Uranium District aerial photograph, shows the extent of the mining disturbance in the district. [ ] Project Hazards and Concerns The purpose of AML Project 16N is to mitigate hazardous conditions and risk to the public associated with open pit highwalls and toxic, acid forming, and /or radioactive mine waste materials. The D9 and K Pits are contiguous open pits characterized by an 8,800 foot long hazardous highwall that averages over 200 feet tall. In addition to the physical hazard presented by the highwall, the project addresses

Jan 1, 2009

By S. H. Ash

THE information obtained by examining and analyzing the core drillings from 15 diamond-drill holes shows that with the proper equipment little difficulty should be experienced while sinking the shafts at the 15 selected sites. Although a number of holes penetrated formations containing a high percentage of silica,, the health hazard from dust can be removed by using proper dust-control equipment. Methane was detected in small amounts in only one (hole 5) of the boreholes. The methane hazard should present no difficulty if adequate ventilation is employed while sinking the shafts.

Jan 1, 1952

By J. K. Whyatt

U.S. Bureau of Mines researchers reviewed an in situ stress estimate developed from measurements of overcore strain taken at test sites on the 7300 and 7500 levels of the Star Mine near Mullan, ID. Although the field measurements of over coring strain were found to be useful, significant deficiencies were found in the stress estimation procedure. A new stress estimate was developed incorporating statistical methods and an improved understanding of stress concentration factors for interpreting overcore strains recorded by doorstopper&apos; cells. Spatial variability of overcore strains and the implications for stress field variability were explored.

Jan 1, 2010