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By Donald P. Richards, William M. Greenslade, Daniel E. Albers

INTRODUCTION The application of oil field technology to large diameter hole drilling is beginning to offer a cost effective alternative to conventional shaft sinking methods. The drilling of ventilation and small production shafts are, of course, not new. The major constraint to the drilling of large diameter production shafts has been the inability to drill holes large enough and straight enough to install and operate relatively high volume hoisting equipment. This paper discusses recent advancements in drilling technology as applied specifically to large diameter holes for use in the mining industry. The paper emphasizes the geotechnical and hydrologic considerations in assessing site conditions and their application to drilled shaft technology. The authors worked together on a recent feasibility study for a 6 m (20 ft.) diameter 975 m (3,200 ft.) drilled shaft in New Mexico. Their individual experience in drilling and geotechnical investigations related to shaft sinking is world wide. DRILLING TECHNOLOGY Large diameter hole drilling has been a natural evolvement of oil well rotary drilling techniques. Most problems that were encountered in the rotary drilling of large diameter holes have been

Jan 1, 1981

By Curt Swanson, David C. Mathy, Dru R. Nielson, Kent VonAspern

In 1997, Central Contra Costa Sanitary District undertook the design of the Martinez East Side Trunk Sewer Improvements Project. Microtunneling was specified for approximately 1,035 meters (3,400 feet) of 600-mm (24-inch)diameter pipeline to be installed through estuarine soil deposits (San Francisco Bay Mud) and alluvium beneath the congested city streets of downtown Martinez, California. Directional drilling was specified for approximately 275 meters (900feet) of 200-mm (8-inch) diameter pipeline in four separate segments to be drilled through bedrock within narrow utility easements between residential properties. This paper presents a case history for the design and construction of themicrotunneling and directional drilling aspects of the project.

Jan 1, 1999

By Donald E. Scheck

Blasting practices based on sound engineering principles are well established but the successful application of these practices requires accurate information about the overburden geology and close supervision of the drilling and blasting operations. Good design alone is not sufficient to insure good results, but the process may be difficult to control unless steps are taken to measure the variables and to provide management and the operators with the information they need to establish and maintain control. Satisfactory blasting can be defined as loosening and fragmenting the rock so that it can be handled by the excavating equipment, while at the same time, governmental regulations on air blast and ground vibrations are not violated. Optimum practices achieve these objectives at the lowest combined cost of the drilling and loading operations and the blasting materials. Total system optimization, that is, taking into consideration the effect of fragmentation on the cost of operating and maintaining excavating equipment as well as drilling and blasting costs, probably is not a reasonable goal at the present time.

Jan 1, 1984

By R. Todd Swinderman

Impact cradles are installed below the belt in conveyor loading zones to cushion the forces from material loading. In this paper, the author will discuss the need for and then explain the new CEMA standard for engineering of impact cradles. He will review the engineering theory and work through an example to demonstrate the assumptions used in the standard do not inappropriately affect the CEMA rating system.

Jan 1, 2002

By Dr. Jack M. Gillette

A system of models which simulate surface coal mining operations has been developed for use in mine planning and economic evaluations. Micromodels simulate individual mine operations for equipment selection and mine planning. Macromodels simulate all operations in the complete mine for economic evaluation of reserves. A cash flow analysis model makes a complete discounted cash flow analysis to deter-mine a required coal sales price or return on investment for evaluation of any mining project.

Jan 1, 1978

By Carl D. Wood

Traditionally, when one considers the optimization of a flotation circuit, the scope of work focuses on a review of unit process equipment. This usually includes topics such as grinding ball typed, grind size, classifier efficiency, mill liner design, chemical reagent addition rates, alternative chemical reagents, on-line process analysis, and automated control strategy. However, since very few companies can afford the capital expenditure needed to completely automate the processes, the flotation operator remains as a critical link in optimization of the circuit. Therefore, upgrading of operator skills and knowledge through training must be considered as equally as important as unit process review. This paper will review some concepts and approaches to innovative operator training. INTRODUCTION Consider for a moment the fantastic changes that have occurred in process automation at many flotation plants during the last several years. Flowmeters, density gages, and on-stream analyzers now routinely measure process conditions and effect control strategy. These functions had until recently been entrusted to human flotation operators. Now with a little stretching of the imagination it is possible to envision a plant where very little human intervention would be required. However, when one begins to calculate the capital cost required to fully install automatic equipment, it quickly becomes apparent that many parts of flotation plants will continue to require skilled, knowledgeable operators to ensure successful operation. Additionally as these automatic systems are put into place, the operator's duties become increasingly complex. Therefore no flotation plant can be considered optimized without upgrading each operator's skill and knowledge to match the technology utilized. BACKGROUND At Henderson, one of the hardest steps towards the optimization of operators was to realize that present level of operator skill and knowledge was not sufficient. Since Henderson had a track record of producing the highest quality molybdenum concentrate in the world, it was difficult to accept the idea that change was needed, or even possible. This realization came about as Henderson began a program to modernize the cleaner plant circuit. Henderson utilizes a complex cleaner flotation circuit involving multiple stages of flotation, with a counter- current routing of flotation tailings. Since start-up in 1976 Henderson had relied upon next-day laboratory analysis techniques, that provided an after the fact measurement of process. Hour to hour process control was implemented by the operator, the basis for the operators' control decisions was primarily the individual operator's experience and "feel'. Bench marking of current flotation technology indicated that on-stream analysis was a proven state-of-the-art method for improving process control. An Outokumpu Courier 30 analyzer was purchased and installed to provide real-time analysis of critical cleaner plant flows. The analyzer quickly began to provide valuable assay information, allowing the metallurgists to develop specific target values for important flotation variables. However due to the complexity of the circuit, the analyzer information showed that a problem was usually caused when several targeted parameters went out of range simultaneously. This made it difficult for the operator to determine just where to implement the proper corrective action. It became apparent that to take full advantage of the new analyzer information each operator would have to become proficient at understanding the material balance of the entire circuit. TRAINING PLAN CONCEPTS With the goal of giving each operator a working knowledge of a circuit material balance the following concepts were applied to develop a training plan: - Most operators were high school graduates, but had fairly weak mathematical skills, and had very little experience at metallurgical calculations. - The training would have to address a wide range of topics from basic fundamentals to complex material balance. The basic sequence decided upon, was to present a fundamental topic to the entire group, break into small groups to work a “hands on'”case study example of that topic, and design the case study results so that they could be combined to highlight a major portion of the material balance concept.

Jan 1, 1993

By H. Verakis, M. J. Sapko

The Pittsburgh Research Laboratory (PRL)1 of the National Institute for Occupational Safety and Health (NIOSH) in collaboration with the Mine Safety and Health Administration (MSHA) Technical Support Center has devised a prototype hand-held instrument which can provide a direct assessment of the potential explosibility of a coal and rock dust mixture. Current Federal regulations require that rock dust be applied in all underground areas of a coal mine to mitigate the propagation of a coal dust explosion. To determine compliance with the Federal regulation, mine inspectors collect dust samples from sections of underground coal mines for an MSHA laboratory analysis of incombustible content. However, the laboratory analysis may not be completed for more than a week or two, during which time the mine area from which samples are taken may be inadequately protected. The operation of the Coal Dust Explosibility Meter (CDEM) is based on the difference in optical reflectance between light rock dust and dark coal dust. For a given coal volatility, the optical reflectance of such mixtures is relatively constant at the limit of explosibility, independent of the coal dust particle size. The CDEM is not intended to replace the current MSHA laboratory analysis of coal mine dust samples for incombustible content, but to serve as a supplemental device for enhancing mine safety through improved rock dusting practices.

Jan 1, 2006

By C. Caceres

Fibre reinforced shotcrete in combination with other types of support systems is becoming the leading support method for underground excavations, especially those present in low quality rock masses. Sudden or rapid ground support failure can expose workers to safety hazards, damage to equipment and others resulting in production interruptions that will impact the cost of operation. Knowing the peak and post-peak strength characteristics of the support system over time are of major importance. Round Determinate Panel Testing of fiber reinforce shotcrete is the primary test used by the mining industry to determine strength characteristics; however, the tests are costly and significant manpower is required in a mine environment to build, store, handle and test the panels. For these reasons numerical modeling can result in an effective method to produce realistic results. This paper examines the strength characteristics Round Determinate Panel tests and its ultimate application in underground excavations, using Itasca?s three dimensional particle flow code (PFC3D).

Jan 1, 2010

By U. Thorley

Management of mine and tailings reclamation activities by surface mining oil sands operations in Alberta, Canada is experiencing increased national and international attention. Of particular concern is the ability of existing mines to execute and fund reclamation activities. Concern stems from a lack of demonstrated tailings reclamation technologies, perceptions of a poor track-record of reclamation activity by industry, and a lack of transparency with respect to the potential cost of reclamation activities relative to the monies secured in Alberta?s Environmental Protection Security Fund (EPSF). Limited information is publicly available regarding reclamation costs and technologies. Available data typically comes from disparate sources. This paper examines the expected costs of oil sands reclamation activities through a study of corporate Asset Retirement Obligation (ARO) liabilities, the Province of Alberta?sEPSF, and published data relating to reclamation costs.Issues relating to current liability funding are introduced.

Jan 1, 2011

By L. Alan Weakly

The U.S. Department of Energy (DOE) has entered into a $l.5 million Cooperative Agreement with Alpine Equipment Corporation/Astro International Corporation ("Alpine") of State College, Pennsylvania, for the evaluation of water-jet-assisted (WJA) mechanical cutting of oil shale under actual mining conditions. A commercial-sized, heavy WJA mechanical miner is being assembled based upon the successful "factory testing" of a smaller prototype miner utilizing standard tungsten-carbide and Polycrystalline Diamond Composite (POC) bits in large oil shale boulders. Actual field testing of the machine will be conducted in an oil shale mine located in the Piceance Basin of Western Colorado. In-mine logistical support is being provided by several oil shale companies through the Colorado Mining Association (CMA) and the U.S. Bureau of Mines (USBM).

Jan 1, 1990

By M. J. Laurila

Elemental analysis of slurry streams using X-ray fluorescence (XRF) has long been employed. However, detector technology has limited the application of XRF devices. Using detector technology employed on NASA's Mars Pathfinder to analyze soil samples, Process Control, Inc. has developed an on-line analyzer to mount on a sampling system. The prototype XRF elemental analyzer was installed at Detroit Edison's Monroe Power Plant in January, 1998 and has been employed to monitor feedstock quality. A slurry system has been developed for flotation control. This paper describes the testing of the analyzer using the new, draft ISO standard for evaluating the performance of on-line analyzers (ISO/DIS 15239).

Jan 1, 1999

By E. M. Frizzell

Decisions affecting ground control design require detailed knowledge of roof rock geology. This is especially true when weak roof materials and anomalies create hazardous conditions and. if not properly supported, result in roof falls. The U.S. Bureau of Mines has developed a system to evaluate geological conditions by using a roof drill that will provide an estimate of the compressive strength of the roof rock in real time. Through the use of sensors and a microcomputer on the roof drill critical drilling parameters can be interpreted and analyzed almost instantaneously, making it possible to inform an operator of hazardous roof conditions such as voids and changes in strata during the drilling process. Geotechnical data can be downloaded to a portable semiconductor memory device, which is brought to the surface so that data can be directly accessed with a personal computer for further analysis. Results from field tests are presented.

Jan 1, 1992

By C. E. Larson

Man's use of 'glass predates recorded history. Although early man had no knowledge of how to form glass, artifacts have been found near naturally occurring glass formations where molten rock had been rapidly cooled. In areas where volcanic activity is evident, primitive people fortunate enough to have lived in that area used the naturally formed glass to make arrow heads, knife blades, tools and ornaments. These glass artifacts have been found all over the world. In fact in todays modern society there are recorded cases of aboriginal tribesmen in Australia fabricating arrowheads from glass bottles. 2. A Brief History of Glass The first evidence of man made glass were beads made around 2500 BC by the Egyptians. The Mesopotamians also made glass beads at about the same time.

Jan 1, 1986

By John Hanna

Recently. researchers at The University of Alabama have developed a two-step method for the treatment of phosphorus sludge that includes bulk removal of phosphorus by physical separation techniques followed by remediation of the residual P4 in the sludge using a novel wet air oxidation technique known as "HSAD", Tests made on samples of the electric furnace phosphorus sludge have demonstrated that essentially complete and fast removal of the P4 in the sludge can be achieved by the HSAD wet oxidation treatment, Further studies were made to determine the applicability of the two-step process on sludges of various origins. P4 contents different pre-treatment and storage conditions, The present work discusses the mechanisms and factors controlling the HSAD wet air oxidation remediation approach.

Jan 1, 1992

By Kathleen Kreiss, A. James Ruttenber

INTRODUCTION Early in the morning of July 16, 1979, there was a breach in the earthen retaining dam of a tailings pond at the United Nuclear Corporation's (UNC's) Church Rock uranium mill. The acidified liquid and tailings slurry spilled through the damaged portion of the retaining wall into an arroyo that is a tributary to the Rio Puerco river system. The Rio Puerco runs through Gallup, New Mexico, and eventually crosses the New Mexico-Arizona border (Fig. 1). On its way to Gallup, the Rio Puerco and its tributaries pass through land with a checkerboard pattern of ownership, with portions owned or leased by the Navajos, individuals, the Bureau of Land Management, and the State. In terms of tailings liquid volume (3.6 x 108L; 94 million gal), the UNC spill ranks as one of the largest. The mass of solids released in the slurry (10.0 x 105 kg; 1 100 tons) appears to be close to the median for accidents of this kind, however [U.S. Nuclear Regulatory Commission (NRC), 1979]. The UNC first opened its Church Rock uranium mill in 1977 on land adjacent to acreage belonging to the Navajo tribe. The mill, which is next to the UNC Church Rock mine, is located approximately 16 km (10 miles) northeast of Gallup, New Mexico (Fig. 1). Gallup, a town of 18 000 people, is the closest population center. The region surrounding the plant site is sparsely populated by Navajos, at a density of approximately 5.8 persons/km2 (15 persons/sq mile). The UNC mill and mines employ approximately 650 persons, and the adjacent Kerr-McGee uranium mine employs about 300. The UNC mill normally processes 3.2 x 106kg/day (3 500 tons/day) of uranium ore, depositing the acidified tailings slurry in a series of three earthen holding ponds. The tailings ponds are located east of the pipeline arroyo that feeds into the Rio Puerco approximately 2.4 km (1.5 miles) from the southernmost tailings dam. The liquid portion of the tailings slurry evaporates in the ponds; hence, under normal conditions, there is no surface flow from the holding ponds to the arroyo. Both runoff from the plant site after heavy rains and possible seepage from the tailings ponds may deliver radionuclides to the arroyo-river system, however. The dam across the southernmost tailings pond was considered to be in keeping with the state of the art. However, the New Mexico Environmental Improvement Division (NMEID) had warned UNC about dangers of locating the pond over a heterogeneous geological formation. The state Engineer's Office approved of the site only after UNC agreed to strict design criteria. Others have pointed to dangers of constructing earthen dams for impoundment of uranium mill tailings (Carter, 1978). Causes of the dam break were multiple: the UNC mill filled the tailings pond to a level that exceeded permit criteria; the tailings pond was lined improperly; the dam was constructed using clay that was compacted excessively, resulting in cracking and subsequent seepage; and the unstable substrate beneath the dam permitted differential settling. The UNC Church Rock mine has continuously released dewatering effluent into the pipeline arroyo at a rate of 88.3 L/sec (1 400 gal/min) since 1968. Before 1975 this effluent was not treated; after 1975 it received precipitation treatment for removal of Ra-226. Radionuclides are also released into the river system through the dewatering of the Kerr-McGee uranium mine 1.6 km (1.0 mile) north of the UNC mill. During usual mining operations, approximately 227 L/sec (3 600 gal/min) are released into the pipeline arroyo and subsequently into the Rio Puerco. The Kerr-McGee mine began continuous release of dewatering effluent in January 1972. In 1974 Kerr-McGee began Ra-226 precipitation treatment of its dewatering releases, but NMEID data indicate that treatment has often been incomplete. The effluent from both mines has been responsible for transforming the downstream portion of the Rio Puerco from a sporadically dry riverbed into a continuously flowing stream and has contributed to the current levels of background radiation along the river system (Table 1). This paper will summarize the postspill monitoring efforts and relate the assessment of this spill to the general question of evaluating the health effects of nuclear fuel-cycle wastes. The data pertaining to the measurement of radionuclides in the Church Rock environment and the radionuclide concentrations in animals will appear in forthcoming reports. CHURCH ROCK HEALTH EFFECTS ASSESSMENT APPROACH The initial health effects evaluation involved identifying the radionuclides that were released into the river system from the tailings pond. Table 1 lists the State of New Mexico maximum permissible radionuclide concentrations for liquids released to unrestricted areas, the typical tailings liquid concentrations, and postspill river water concentrations. The tailings liquid contained comparatively high levels of Th-230, Ra-226, Pb-210, and Po-210--all of which, according to postspill river water samples, had exceeded the state maximum permissible concentrations (MPC) at one time or another. After the radionuclides in the tailings were identified, pathways through which humans could be exposed were clarified. Environmental monitoring data were then used to quantify the important pathways of human exposure. Water samples were collected from the river, from test wells dug near

Jan 1, 1981

By B. V. Close

Surface mining regulations together with mine and reclamation planning require collection of large amounts of geologic and hydrologic data for both new and existing mines. Recently developed microcomputer software facilitates the integration of this information from computer databases into ground-water flow models. The databases are used to identify areas which require dewatering and/or depressurizing and for generating contour maps of aquifer parameters. Gridded versions of these contour maps are incorporated into finite difference ground-water flow models which are used to design dewatering and depressurizing well fields and to estimate the effects of ground-water pumping and pit progression on local ground-water levels.

Jan 1, 1988

By Jeffrey J. Daniels

Advances in borehole geophysical research for mineral assaying, and remote detection of mineralization away from the borehole. Nuclear activation measurement research has provided accurate in situ assays of economic metals with neutron-gamma activation, using a high resolution intrinsic-germanium detector. Although nuclear activation analysis is the present "best-hope" for obtaining in situ assays for some elements, gamma-gamma and magnetic susceptibility measurements can provide accurate assays for lead-zinc and magnetite, respectively. Borehole optical spectroscopy and x-ray fluorescence are being investigated as possible in situ assaying techniques for some minerals. More laboratory and field calibration research is needed before nonlinear complex resistivity (NLCR) can be routinely used as a quantitative assaying tool. Field tests have shown that variations in the local geologic environment can affect the quantitative accuracy of assay values from downhole NLCR measurements. Deeply penetrating borehole geophysical methods are increasingly being used for mineral exploration as drilling costs and exploration have increased. Borehole electrical measurements have been shown to be useful for detecting conductive orebodies that are not interesected by a drillhole. Hole-to-surface resistivity, and surface-to-hole time-domain electromagnetics are demonstrated to be particularly effective for defining mineralized zones in a massive sulfide environment. Borehole gravity meters and three-component magnetometers have been developed and should prove useful for defining geologic anomalies away from the drillhole.

Jan 1, 1985

By L. H. E. Weyher

In a previous paper presented at the 1966 Annual Meeting of AIME we reported our work, conducted at the Pennsylvania State University, on the hydrocyclone washing of fine coal.' The initial evaluation based on that work demonstrated the feasibility of hydrocyclones as fine-coal cleaning devices, and in that previous paper we presented selected test data that showed in principle how product yield and assay respond to variations of the major cyclone operating variables. The present paper reports in greater detail on the findings and presents a comprehensive evaluation of our data as follows: ? Hydrocyclone throughput rates were related to feed pressure and other variables by regression equations. These equations are compared with other capacity- versus-pressure drop expressions taken from the literature on classification cyclones.

Jan 1, 1968

By J. P. Ducarme

The eastern U.S. contains vast reserves of thin seam coal deposits, particularly in the Appalachian mountain region. These typical 355 to 710 mm thick reserves are difficult or uneconomical to recover with present technology. The U.S. Bureau of Mines is developing technology that would allow nearly 100% recovery of thin seams in these mountaintop regions. This paper details the research that has been conducted on these new techniques and presents results of testing on a cross-ridge full-scale physical model.

Jan 1, 1994

By James McNally, Adam Stremcha, John MacGregor

With 13.7km of TBM tunneling in Atlanta’s hard gneiss well under way, drill and shoot work continues on several sites throughout the city. In order for the City of Atlanta to meet the consent decree imposed by the federal government, an aggressive construction schedule was a necessity. Construction consists of two deep, large diameter tunnels, four construction shafts, a pumping station, one overflow shaft, three large intake structures, and two connecting tunnels. Due to the multitude of blasting insensitive urban environments, a high standard of seismic and air-overpressure criteria, coupled with time restrictions, was adopted for the project. At any given time, drill and blast operations were under way at four of the seven sites requiring a certain amount of coordination between the TBM excavation, surface work, and the forces of Mother Nature. This paper addresses the challenges faced and the techniques used to safely and successfully complete the rock excavation of the West Area CSO Tunnel and Pumping Station project.

Jan 1, 2007