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By D. W. Hill

By seeking to define the social and political parameters of both established and potential uses of the underground, this paper will attempt to formulate and state the problem posed in the realms of public choice for obtaining more rapid development and more beneficial use of the underground environments. Essentially, the paper will pursue the following outline: 1. Established policies and established uses of the underground 2. Potential uses of the underground for social benefit 3. Constraints on development and policy a. Psychological constraints b. R & D plus physical constraints c. Economic constraints d. Public choice and policy contraints (both governmental and non-governmental) e. Legal and other structural constraints 4. Defining the problem from the social standpoint 5. Suggestions for surmounting the constraints and meeting the problem: some hypotheses for the future.

Jan 1, 1974

By Ahmet Gursoy

Maryland, will be the widest vehicular tunnel ever built by the trench tube method. Careful coordination and planning were required to meet the tight and fast design and construction schedules. During the preliminary design, traditional design drawings were bypassed in favor of 25 preliminary design reports representing major work breakdown structures (tasks). For each task, alternative design solutions were examined and analyzed by means of trade-off studies on the basis of engineering, constructibility, and economic considerations, thus providing an overall conceptual value engineering approach for the entire project. So far, total value engineering proposed by the contractor for Contract I I (largest contract of the project at $245 million) is less than 1.5 percent of the contract value. This is an important indication of the success of the design phase planning.

Jan 1, 1983

By M. O. Woodburne

The Mojave Desert province is comprised of a diverse group of mountains that range in elevation from about 2,000' (600 m) to 3,000' (900 m), separated by tracts of alluvial cover. The province is bounded on the southwest by the San Andreas fault, on the north by the Garlock fault, on the east by the Death Valley- Granite Mountains fault. Rocks preserved in the Mojave Desert Province collectively record a rich assemblage of Precambrian crystalline basement' ranging in age from ca. 1.8 to 1.35 Ga, upper Precambrian and Paleozoic Cordilleran miogeoclinal sediments and platform rocks, Mesozoic backarc and interarc shallow marine and continental sequences, locally emplaced Permian- Triassic syenitic plutons, extruded hypabyssal volcanic rocks of the ?Jurassic "Sidewinder Volcanic Series," and regionally intruded late Mesozoic granitoid batholithic rocks (Dokka et al., 1988). The Mojave block apparently was a high-standing element for much of the early Tertiary, with strata of Late Cretaceous or early Tertiary age preserved only on its margins. Beginning about in the late Oligocene an intense episode of regional north-south extension was developed in a roughly east- west trending belt that traversed the central part of the province. This extensional belt has been termed the Mojave Extensional Belt. The extensional regime lasted from about 22-17 Ma, and is generally divided into two phases. The first, from about 22-20 Ma records intense extension via the activity of crustal-scale, simple shear, low- angle normal faults, high-angle normal faults, and extensional fracturing, along with intrusion of intermediate to silicic volcanic rocks, including episodes of explosive volcanic activity. The Peach Springs Tuff, a major regional marker unit that extends across the Mojave from Arizona to about Barstow, forms an effective stratigraphic lid on the extensional interval, (i.e., is not rotated) and is dated isotopically at about 18.5 Ma. The extensional episode was followed by an interval of high- angle normal faulting and dike emplacement from about 19 to 17 Ma, and was accompanied by at least local uplift and volcanism. Most volcaniclastic and epiclastic sedimentary units of the central Mojave block post-date the interval of extension and normal faulting, and occur as a complex of marginal alluvial and more interior lacustrine facies that formed as recently as late Miocene (ca 13 Ma). Local sequences (e.g., Lava Mountains) record deposition up to about 8 Ma, but there appears to be a regional "gap" from then until at least local successions record Pleistocene deposition. Magnetic and isotopic age studies indicate a complex history of crustal rotations, distributed across a number of discrete domains, during the past 10 Ma. Some of the youngest volcanic and geomorphic features apparently developed at "holes" formed at the edges of rotated blocks.

Jan 1, 1995

By Y. Topkaya, R. E. Johnson, B. R. Palmer, R. B. Bhappu, A. E. Clark, R. P. Bush, L. E. Schultze

The U.S. Bureau of Mines conducted copper exchange capacity (CuEC) tests for six common clays under simulated in situ leaching conditions. Regression equations were obtained from the data expressing the CuEC as a function of Cu concentration, pH, and temperature. Further testing resulted in regression equations expressing CuEC's of Na and Ca montmorillonites and attapulgite as a function of Cu concentration, pH, and the concentration of metal ions which compete with Cu for exchange sites. Using these equations, an analysis was made of the impact each clay could have on overall copper recovery. The results suggest that Ca and Na montmorillonite clays could have a major impact on Cu recovery and that attapulgite and illite clays could have a smaller, but still significant, impact. Kaolinite and ripidolite clays pose little threat to loss of copper from in situ leaching solutions. Copper losses are decreased by the presence of competing ions, and A1 and Mg have the largest impact of those ions normally present in Cu leaching solutions.

Jan 1, 1993

By Ruoming Gong, Arindam Samanta, Ragula Bhaskar

Three studies conducted at the University of Utah relating to the effect of scrubbers on face airflow patterns, the resulting dust exposure of operators and the development of a throat scrubber for continuous miners are summarized in this paper. The first study involved full-scale laboratory tests to determine the potential dispersion patterns and transport of dust at a continuous miner face, using different ventilation configurations and a scrubber. Concentration maps were developed and potential exposures at operator positions were examined. The second study involved the development of a 3-D numerical model to predict airflow patterns generated by a scrubber at a continuous miner face. The model was designed to evaluate the role of various face parameters on airflow patterns at a miner face and to complement the full-scale testing. The third study involved the design and fabrication of a low profile hydraulically powered continuous miner throat scrubber. The scrubber uses three hydraulic motors and small diameter fans to draw about 3000 cfm (1.42 m3/s) of air and uses a flooded bed scrubber to filter dust particles.

Jan 1, 1993

By S. Triantafyllidis

The tailings produced from the Kirki (Agios Filippos) high sulfidation epithermal deposit processing plant are laminated, weakly cemented and their particle size ranges from fine sand to fine silt. They are mainly composed of milling residues of gangue (quartz, dickite/kaolinite, pyrophyllite, illite); sulfides and secondary minerals (jarosite group minerals, butlerite, anglesite, beudantite and gypsum) are present to a lesser extent. They have high Pb and Zn (average 0.75 % and 0.57 % respectively) and low S (1.04 to 2.92 %), Cu, As, Cd, Ni and Sb content (average 248, 163, 59, 27, 20 g/t respectively). Stagnant waters forming small ponds on the surface of the impoundments exhibit low pH and high heavy metal and sulfate concentrations. Negative Net Neutralization Potential (NNP) characterizes the tailings, indicating moderate to high potential for acid generation. Application of the TCLP test revealed that the tailings are characterized as toxic because of the increased solubility of Pb and Cd. On the other hand, As TCLP solubility is very low.

Jan 1, 2006

By A. Unal

Coal resource characterization usually calls for estimating more than one variable over a block or node simultaneously. Within the realm of geostatistics, each variable has been evaluated independently from the others assuming a lack of significant correlation. Research conducted with coal seams, however, has shown that the variables of immediate interest, such as seam thickness, ash, sulfur content, and density depict some correlation schemes in distinct zones, if not throughout the entire area. The above findings have two immediate consequences : (1) correlation analyses provide guidelines to determine the geologically distinct zones, and (2) where possible, cokriging should be used instead of kriging. This will maximize data utilization decreasing the frequently criticized high estimation errors. The cokriging formulation will also provide more accurate estimates for under sampled variables using better-sampled ones. This is a common case with coal with regard to the non-cored reconnaissance drill holes for which only very few variables were recorded. A case study illustrates the improvements that may be obtained by taking advantage of the intervariable correlations.

Jan 1, 1986

By Greg Barfoot, Kurt Keskimaki

The Henderson Mine is located approximately 50 miles west of Denver, Colorado. A project is underway to replace the existing rail system which transports molybdenum ore 15 miles from the mine to the mill using three flight conveyor system. The first conveyor is a 1 mile, high lift conveyor which transports the ore from an underground crushing station to the end of the existing rail tunnel. The second conveyor is 10 miles in length and utilizes the existing rail tunnel to transport the ore from the mine, which is on the east side of the Continental Divide, to the mill located on the west side. The third conveyor takes ore from the tunnel portal to the mill through a series of 7 horizontal curves and inclines up to 15 degrees. The project applies advanced conveyor design to tackle the installation of the system in an operating mine and achieve the highest possible level of reliability. This paper outlines the design process for this system, discusses the options which were evaluated and how the current design evolved.

Jan 1, 1998

By Annan Cook

Cyprus Metals' Sierrita mine is located in the Pima Mining District, Pima County, Arizona (Fig. 1), which is one of the largest known porphyry copper districts. The ore body is part of a large mineralized system that includes Cyprus' adjoining Esperanza mine. The copper and molybdenum grades being mined at Sierrita make it one of the two lowest grade porphyry copper mines in the world Mineral production from the district was first recorded in 1876. Copper from replacement deposits in carbonate rocks and copper¬-lead-zinc from veins in volcanic rocks were mined from several deposits. However, it was not until 1957 that the district commenced to become a major copper producer with the beginning of production from the Pima mine, which was the first open pit operation. Since that time, seven other open pit mines have come into production. Because of the variable copper prices and high operating costs, not all of the mines are operating today. A map of certain outcrops, plutons, and open pits, as well as older underground mining operations, in the Pima district is shown in Fig. 2.

Jan 1, 1991

By Richard R. Klimpel

The author was the banquet speaker at the 48th Annual MPD meeting, sponsored by the SME Colorado Minerals Processing Section, May 14-16, 1998, in Colorado Springs, CO. Here are his remarks. It has been an exciting experience to have spent 34 years involved with the process of generating patented technology eventually leading to commercialization. In today's terminology, this process is called technology transfer. I have had the unusual experience of being involved doing basic research as an inventor while also being responsible for managing new product development and commercialization. In addition, I worked for 31 years before my retirement for a large research-oriented company, The Dow Chemical Co. In 1995, the company spent more than $1 billion dollars on research and development. The last three years of my career have been spent working with a research-oriented university, The University of Florida. And I have worked as a consultant helping several companies to optimize their products and processes. It is on this cumulative experience base that the preparation of this article is based.

Jan 1, 1998

By Allen J. Sobczak, Peter J. Peters

The five tunnel contracts of Milwaukee Northeast Side Relief Sewer System are about 80 percent complete. The tunnels are all excavated for 1.9 meter (6'-0") finish diameter sewers in a variable rock, mixed face, and glacial soil environment. Different contracts were let under two primary types of specifications, performance and prescriptive, which treated aspects of construction, such as primary ground support and groundwater control, differently. Interfacing of design and construction through field personnel allowed the needs of all parties to be met and resulted in savings in time and money to the Milwaukee Metropolitan Sewerage District (MMSD). Interfacing, cooperation and risk sharing allowed resolution of problems such as line and grade variations and potential differing site conditions. It also allowed the parties to pursue constructive changes to construction activities. Thus on one contract prescribed use of compressed air was eliminated, but migration of fines into the tunnels was stopped with filter fabric. Use of an expensive primary support system was dropped, but concern about deterioration of lagging was alleviated by use of special materials.

Jan 1, 1983

By Frederick W. DeVries

The following charts were presented at the Randol Gold & Silver Forum 2000, held at the Hotel Vancouver (Vancouver, B.C.) from April 18-21, 2000. It must be borne in mind that the "facts" stated and con­clusions drawn by the author were not as the result of a rig­orous technical investigation, but rather as a member of a journalistic team seeking a rapid view for presentation as news to a TV audience. Since the author's visit, some retrenchment on the part of the operators on estimating the cyanide content of the spill seems to have occurred. This does NOT alter the conclusions that (a) the spill was an intolerable embarrassment for the world mining industry, nor (b) the potential damage to future mining investments, should prompt action not be taken: 1. to understand the reasons for the dam failure, and 2. to draw up firm concepts of how to avoid future fail­ures of dams at mining properties containing materials that are toxic, environmentally unfriendly, or with as highly dis­comfiting a profile as cyanide.

Jan 1, 2000

By William B. Thayer, James H. Meinholz

The Milwaukee Metropolitan Sewerage District (MMSD) has been working since mid-1977 on a fast track to meet a court-imposed schedule to rehabilitate a large wastewater collection and treatment system at an estimated cost of $1.7 billion. Because of glaciation, the Milwaukee area has an extremely complex geologic environment. The rock surface ranges from outcroppings in the northern and western parts of the area to 76 m (250 ft) below the surface at the mouth of the Milwaukee and Menomonee Rivers. Bedrock beneath the glacial mantle is a thick sequence of early to middle Paleozoic sedimentary rock. To cope with the many complexities of this large public works project, a Program Management Office (PMO) concept has been employed. A Geotechnical Engineering Group was established within the PMO to provide a continuous , unified approach to geotechnical engineering and full disclosure of all geotechnical information in the construction contract documents. It provides qeotechnical engineering to design and construction, develops and maintains a qeotechnical data base, and participates on the claims resource team.

Jan 1, 1983

By F. Calizaya, I. Duckworth

An ore-pass is an underground conduit used to transfer ore from one level of a mine to another. This method of transportation depends on the elevation energy only; therefore, it has very low operating cost. However, two inherent problems may hamper this process: (1) hang-ups of interlocked pieces and (2) a sudden release of trapped air from the ore-pass (belching). These events can create unsafe conditions with the potential for catastrophic consequences. This paper presents a summary of CFD modeling studies that were formulated to investigate the pressure build-up and belching of dust and rock particles from long ore-passes. The models were calibrated against field data collected from an actual ore-pass system and used to predict the airflow-pressure distributions in the mine for various ore feed rates and ore-pass geometries. P.T. Freeport Indonesia’s Grasberg ore-pass system (240,000 tpd capacity) was used for this purpose. This system comprises of four active ore-passes, with each being more than 600 m in vertical length.

Jan 1, 2004

By Kaye P. Strong, Desmond M. Levins, Anthony G. Fane

1. INTRODUCTION The safe disposal of tailings is the most important environmental question facing the uranium mining industry today. This is because tailings present a major long term radiological hazard as they contain about 71% of the radioactivity originally in the ore. The magnitude of the problem can be appreciated by considering the quantity of tailings involved. For example, projections of milling programs in Australia indicate that there will be 100 million tonnes of tailings produced by the year 2000 (Levins 1980). The United States currently has in excess of 100 million tonnes and by the year 2000 will have between 900 and 1700 million tonnes (Landa 1980). Present options for tailings rehabilitation include leaving them above ground, returning them to the mine or placing them in specially excavated pits. In any event, the tailings will be covered with earth and revegetation attempted. This will remove the problems of airborne radioactive dust and water erosion of the tailings, at least in the short term, but diffusion of radon-222* from the tailings may still occur. The Atomic Energy Control Board of Canada (1981) has proposed a maximum allowable radon flux from rehabilitated tailings of 0.074-0.37 Bq m -2s-1(2-10 pCi M-2 s-1); the exact level is to be determined "after discussion with other regulatory agencies and the industry". The United States Nuclear Regulatory Commission (USNRC 1980) has been more restrictive in recommending a maximum flux of 0.074 Bq m -2s-1 (2 pCi m-2s-1). As a guideline they also suggested a minimum depth of covering material of 3 m to achieve this surface flux for tailings typically found in the western milling regions of the United States. The design of rehabilitation schemes is aided by a knowledge of radon transport through tailings piles. In this paper we present the results of a theoretical analysis and experimental study of radon diffusion through selected Australian tailings and cover material. The minimum cover criteria of 3 m is reexamined in the light of these findings. [ ]

Jan 1, 1981

By James A. Clum

The shift to lower grade iron ores, e.g., magnetic taconites, resulted in a shift towards agglomeration practices which could effectively deal with the fine particle sizes generated in the liberation and concentration processes. If the iron bearing particles are not extremely fine, e.g., -1/2 in + 100 mesh, sintering is an adequate means of agglomeration.(1) For the more dispersed ores which result in fine concentrates (more than 80%,-325 mesh), the fine particles must be agglomerated by mechanical means before final hardening, e.g., pelletizing.(1) In the pelletizing process, the essentially mechanical step of balling is extremely critical since the strength of the pre-fired pellet determines the firing conditions. The ability of the proper amount of moisture to hold together a ball of the very fine ore concentrate particles has long been recognized. It is a charac¬teristic of the reaction at the interface between the ionic solid of the ore concentrate and the polar water phase which overlays the solids. The strength in such moisture laden balls, the green strength, is a strong function of the water content (Figure 1) and thus deteriorates rapidly for either a small excess or a small deficiency of moisture. For purposes of commercial practice, the control of green ball handling properties by accurate control of ball moisture is too demanding. Moreover, as the ball is heated towards its hardening tempera¬ture, e.g., 1300'C, there is a substantial drying reaction which would lead to such a low dry strength of the ball that it would not support its own weight much less the weight of other balls in a firing furnace.

Jan 1, 1976

By P. Bartel

Coal cleaning can be effected by the bacterium Sulfolobus acidocaldarius, which in oxidizing sulfur and dissolving mineral matter requires carbon dioxide and oxygen; carbon dioxide as a carbon source and oxygen as an electron acceptor. The desulfurization of coal by thermophilic bacteria under elevated partial pressures of carbon dioxide and oxygen was studied at a total pressure of 1 atm. The partial pressure of carbon dioxide was varied over the range 0.00032 to 0.33 atm (0.00032, 0.007, 0.10, 0.33 atm), and the partial pressure of oxygen was varied over the range 0.14 to 0.40 atm (0.14, 0.21, 0.30, 0.40 atm). The maximum rate of coal desulfurization increased by 32%, from 9.0 to 11.9 mg S/1 hr, as air was enriched in carbon dioxide from its atmospheric level of 0.00032 atm to 0.10 atm. Enrichment with carbon dioxide up to 0.10 atm, at constant oxygen partial pressures, increased the desulfurization rate, but enrichment to 0.33 atm caused the rate to decrease. At constant carbon dioxide partial pressures, the desulfurization rate was maximum at oxygen partial pressures of 0.21 and 0.30 atm. At higher (0.40 atm) and lower (0.14 atm) oxygen partial pressures the rate decreaed by 9 to 20%. The desulfurization rate decreased by 58X, from 9.0 to 3.8 mg S/1 hr, when the air pressure was increased from 1 atm to 3 atm. The effects justify an economic analysis during design and operation of a commercial air feed in a process to desulfurize coal by microbial action.

Jan 1, 1986

By Michael Fehler, Hidenshi Kaieda, Leigh House

Hydraulic fracturing has gained in popularity in recent years as a way to determine the orientations and magnitudes of tectonic stresses. By augmenting conventional hydraulic fracturing measurements with detection and mapping of the microearthquakes induced by fracturing, we can supplement and independent1 y confirm information obtained from conventional analysis. Important information obtained from seismic monitoring includes: the state of stress of the rock, orientation and spacing of the major joint sets, and measurements of rock elastic parameters at locations distant from the wellbore. While conventional we1l 1ogging operations can provide information about several of these parameters, the zone of interrogation is usually limited to the immediate proximity of the borehole. The seismic waveforms of the microearthquakes contain a wealth of information about the rock in regions that are otherwise inaccessible for study. By reliably locating the hypocenters of many microearthquakes, we have inferred the joint patterns in the rock. We observed that microearthquake locations do not define a simple, thin, planar distribution, that the fault plane solutions are consistent with shear slippage, and that spectral analysis indicates that the source dimensions and slip along the faults are small. Hence we be1 ieve that the microearthquakes result from slip along preexisting joints, and not from tensile extension at the tip of the fracture. Orientations of the principal stresses can be estimated by using fault plane solutions of the larger microearthquakes. By using a joint earthquake location scheme, and/or calibrations with downhole detonators, rock velocities and heterogeneities thereof can be investigated in rock volumes that are far enough from the borehole to be representative of intrinsic rock properties.

Jan 1, 1986

By Richard R. Klimpel

INTRODUCTION The purpose of this paper is to summarize the current status of reagents used in the mineral industry plus present some current challenges and possible new technologies of the future. Table 1 lists the important families of reagents which, when taken together, constitute at least 95% of the current commercial reagent market. A very approximate estimate of the free world reagent market size in mineral applications is about 1.5 to 2.0 billion dollars (U.S.) using 1985 data. Obviously, to serve such a large market requires the effort of many different types of commercial supply sources. It is estimated that there are over 300 industrial firms in the free world that have a dedicated business/technical structure for supplying reagents related to the mining industry. There are a number of characteristics which are associated with the product families listed in Table 1. Understanding these characteristics helps to provide a realistic economic/technical basis for outlining future challenges in mining chemicals. 1.Essentially all of the products listed are old chemistry in the sense that the molecules have been known and manufactured for at least 25 years. This has not been a highly dynamic field of endeavor from the viewpoint of new product introduction. 2. The greater majority of the products listed can be viewed in commercial terms as "commodity" chemicals, that is, they are available from many sources and the pricing of a some- what generic product generally dominates differences in product quality or uniqueness. With commodity pricing, reagent suppliers significantly reduce research expenditures, loosen product quality somewhat if the applications of the reagents allow, etc. in order to be cost competitive.

Jan 1, 1989

By Robert W. Buechley, Charles R. Key, Jonathan M. Samet, Marion V. Morgan, Arnolfo A. Valdivia

INTRODUCTION The Uranium Epidemiology Study at the University of New Mexico was initiated in 1977 with the objective of assessing health effects of uranium mining in the Grants, New Mexico, area. The planned approach was a cohort study of mortality that would capitalize on the availability of health records at the Grants Clinic. During the first year, emphasis was placed on determining the feasibility of the proposed study: Were adequate records available? What was the quality of available information? Could a cohort be established? The first year's work confirmed the study's feasibility (Buechley, 1979). Subsequent efforts have focused on the health and exposure data base and comprehensive follow-up. A retrospective cohort study of early miners is in progress; a prospective cohort study of miners who began working under the current Federal standard is planned. This report will summarize the current status of the Uranium Epidemiology Study. A chronology of the study's activities follows (Table 1). TABLE 1. Uranium Epidemiology Study Timetable 12/77 Official start of study. 12/77-8/78 Abstracted Grants Clinic records of 21,780 persons examined for mining companies from 7/57 through 12/76. Checked company personnel records to establish who had worked underground 1 year or more through 12/76. 7/78- Obtained physical exam and mining history information on qualified miners from Grants Clinic and companies. 9/78- Obtained working level month information from companies and other sources. 12/78- Checked qualified miners list with New Mexico death tapes and New Mexico Tumor Registry files. 9/80- Submitted qualified miners list to Social Security Administration for search of its records. 12/80- Obtained copies or abstracts of early State Health Department and Mine Inspector's reports. 3/81-4/81 Conducted Pilot Respiratory Disease Survey. 3/81- Verified underground status of qualified miners via company personnel records. 3/81- Verified smoking and mining histories of qualified miners via Grants Clinic records. 3/81- Began establishing cohort with first underground experience after 1970. 4/81- Checked qualified miners list with Post Office, Voter Registration Office, Motor Vehicle Division, telephone directories, city directories, and other sources. BACKGROUND Uranium Mining in New Mexico The Grants, New Mexico, uranium belt measures some 110 by 25 miles in Cibola, McKinley, and Sandoval counties (Kelley, 1963). The three chief mining districts are, from east to west, Laguna, Grants, and Gallup. Average annual production was about 5,500 tons, or 45% of United States uranium, from 1966 through 1978. Despite a drop in this figure in 1979, to 40%, New Mexico still leads the nation in uranium reserves and production (Hatchell, 1981). In 1918 carnotite, a yellow uranium vanadate, was identified in the Shiprock area (Chenoweth and Learned, 1980; N.M. Energy and Minerals Department, 1981). It received little attention at the time because of its apparently limited volume. In 1950 an important uranium outcropping was discovered by chance in limestone at Haystack Butte, northwest of Grants. In 1951 deposits were discovered in sandstone at Poison Canyon, north of Grants, and at Jackpile, northeast of Laguna. In 1955 finding of radioactive cuttings at an abandoned oil test site near Ambrosia Lake led to drilling and discovery of the first underground deposits (Melancon, 1963). Ore bodies were also found near Church Rock in the 1950's (Rautman, 1977). A uranium rush followed. At various times during 1952-1962, 60 mines and 5 mills were in operation (Gay, 1963). In the early 1960's the price of uranium fell, and many miners left the area. Subsequent market fluctuations have produced shutdowns and consolidations, development and expansion. Many early uranium miners came to New Mexico with

Jan 1, 1981