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By Bobby C. Carson

INTRODUCTION The National Park Service is entering the seventh year of monitoring caves for the presence of radon and radon daughter products. The purpose of this paper is to summarize the radiation monitoring program at Mammoth Cave National Park, and to present some of the results of this program. Mammoth Cave National Park completed five years of collecting data on May 1, 1981: although Mammoth Cave encompasses approximately 361 km of underground passageways, this paper will concentrate on only a 2.2 km section of the cave known as the Historic Tour. Included in this paper is a discussion of the methods the Nations Park Service uses to protect employees from exposure to alpha radiation. MONITORING METHODS The National Park Service monitors cave atmospheres utilizing the procedures provided by the Mine Safety and Health Administration in their Radiation Monitoring Training Manual (Anon., 1976). This procedure is described as the Kusnetz Method (Kusnetz, 1956) of radon daughter monitoring. Due to the length of the tours at Mammoth Cave, it has been determined to be the most practical procedure. The Historic Tour is a 2.2 km (1.4 mile) loop through passageways ranging in size from 18 m high by 12 m wide, to 0.9 m high by 0.6 m wide. Seven five minute walking samples were taken for this cave tour by drawing at least 10 1 of air through a 25 mm fiberglass filter utilizing a Monitaire Sampler Pump. The radon daughter concentration levels were determined using an alpha scintillation counter to measure the alpha activity on the filter paper. The Monitaire Sampler Pump was calibrated each day prior to monitoring the cave tour and the scintillation counter was calibrated by procedures described by the Mine Safety and Health Administration (Beckman, 1975) at six month intervals. Guidelines established by the National Park Service and approved by the Mine Safety and Health Administration require weekly sampling when the average working level exceeds 0.30 (NPS-14, 1980). A working level is an atmospheric concentration of radon (Rn-222) daughters which will deliver 1.3 x 10 5 MeV of alpha energy per liter of air in decaying through Ra C' (Po-214). The Historic Tour has continually exceeded the 0.30 working level average and has been monitored weekly. Generally, only radon daughter working level data has been collected on the Historic Tour due to limited personnel. However, other special measurements of the uncombined fractions of radon daughters with wire screens, tsivoglou method for radon daughter sampling (Thomas modification, 1970), and thoron daughter monitoring. These special measurements have not been routine due to time limitations involved in radon daughter sampling of other occupied portions of the cave. SUMMARY OF DATA The Historic Tour has been the most consistantly monitored tour since elevated levels of alpha radiation were found to exist at Mammoth. Cave. It is also the only natural entrance to the main sections of the cave and provided an opportunity to study man made actions upon the natural entrance. For these reasons the Historic Tour was isolated for study. Beginning October 10, 1977, and ending November 20, 1977, a pilot project was undertaken involving the Historic Tour and the practice of covering the natural entrance to this tour with sheet metal in the winter months. The purpose was to study radiation levels on the Historice Tour while the covers were on and off the natural entrance. In this pilot project, comparisons were made with incast air with covers on and off the entrance, and outcast air with covers on and off the entrance. TABLE 1 Incast air Mean W.L. Covers on . . . . 1.46 W.L. Increased 54% Covers off. . . . 0.67 W.L. when covers on Outcast air Mean W.L. Covers on . . . . 1.33 W.L. Decreased 5% Covers off. . . . 1.40 W.L. when covers on The natural entrance was artificially covered in the winter months (Yarborough, 1978) to protect the visitor from the extremely cold incast air, in the first four years of monitoring. The data in Table 1, illustrated in Figures 1 and 2, shows that this action increased the radon daughter working levels on the Historic Tour by 54% when the covers were on the entrance and the airflow was incast. While the air flow was outcast at the natural entrance, it made little difference as to whether the entrance was closed or open. Some interesting findings were observed when

Jan 1, 1981

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 Charles H. Wells

This paper describes a commercial installation of a sophisticated instrumentation and control system designed to maximize the performance of heavy medium cyclones. Samples of plant feed and its products were collected and analyzed for ash content so that measures of efficiency could be determined for plant operation under (1) manual control and (2) automatic (computer) control. The heavy medium cyclone control strategy and its digital computer implementation are discussed in detail. The sample results are analyzed and the economic benefits of automatic control are discussed. Results from the initial data sets quantify the economic benefits of automatic closed-loop control; viz, increased recovery and reduced clean coal variability have been clearly demonstrated.

Jan 1, 1981

By Douglas G. Hubert

To put coal in its proper perspective as a source of energy for electric power production, we must first compare it to other energy sources. A report of the Atomic Industrial Forum dated February 1958 records a number of authoritative though widely varying predictions. The most optimistic of these states that by 1968 there will be a total U.S. capacity of about 6000 megawatts of nuclear power, if growth continues at the present rate. Other sources indicate over 200,000 megawatts of total electrical capacity in utility plants by 1968. This is only 3% nuclear. Therefore, 97% of our total power production will be from non-nuclear energy. Fig. 1 shows the distribution of energy sources of electric utility product- ion in the U.S. as reported by the Federal Power Commission in 1954. Note that less than one quarter of the total is hydro and about one half of the total is coal. For 1957, the Edison Electric Institute reports that of the total steam- electric generation in the U. S., 68.6% was by coal, 7.9% was by oil and 23.5% was by gas. This is an increase for coal and a decrease for oil and gas in those three years. Thus we can conclude that two-thirds of the steam-electric power in the U. S. is now generated by coal. Fig. 2 shows the major markets for coal for 1947 vs 1957. The greatest in- crease has been in the electric utility market, where it has more than doubled in the ten years. One-third of the total coal produced goes to the utilities which now represent coal?s major market. Utilities used 160 million tons of coal in 1957, and the estimated quantity for 1967 is 275 million tons, and for 1977 is 525 million tons. It is predicted that 85% of steam-electric power will be generated by coal in 1975.

Jan 1, 1959

By C. N. Greene

I am sure it is obvious to all of you that a complete program of casualty and property insurance is as necessary for any tunneling contractor as it is for anyone else involved in trade in the United States today. Going beyond those general undefined terms, there are many areas that need specific attention, particularly for contractors, regardless of size. WORKERS' COMPENSATION Workers' Compensation is mandatory in all states and the District of Columbia. In most of the states, private insurance provides this coverage. In a few states, the state operates Workers' Compensation funds, some of which are competitive with the private sector and others are operated on a monopolistic basis. Under a monopolistic setup, you have no choice, you must buy coverage from the state. Self insurance of the Workers' Compensation risk is also an alternative in most jurisdictions. With a contractor operating only in the U.S., the coverage extensions are few in number. If your work brings you anywhere near navigable waterways or land extensions thereof, you should have both U. S. Longshoreman and Harborworkers' coverage, as well as Employer's Liability coverage for the master or members of the crew of a vessel.

Jan 1, 1983

By Gunter Fauth

The setting of tasks for the process control of coal cleaning, and in this connection the requirements for instrumentation can be classified into the following three fields: - Monitoring the operation of individual units, or process steps, - Control of units or process steps, - Control of the entire coal cleaning process with the intention of optimizing the operation and the profitability of the process. Instrumentation is affected by the type of cleaning processes. For introduction Figure 1 shows the simplified flow sheet of coal preparation which is usual in the German Ruhr District and in which desirable places for the measurement of ash, moisture and sulfur content are marked. The preparation plant is supplied with run-of-mine coal from the shaft via a homogenization facility. In a first step of primary classifying the raw feed coal is screened at about 10 mm. The raw coarse coal ( = 10 mm) is sorted by jig washers or heavy-medium separators. the raw fine coal (< 10 mm) at first is pneumatically sized at about 0.5 to 0.75 mm. The fines, the aspirated dust, are a finished partial product which will be added to the final metallurgical or steam coal. The material 10 to 0.75 mm subsequently is sorted in fine coal jigs and dewatered in centrifuges. The sludge obtained with the wet cleaning processes is dewatered in thickeners and fed to the flotation. Concentrate and tailings are dewatered by filters or bowl centrifuges and by chamber filter presses or belt filter presses, respectively. The partial products coarse coal, fine coal, flotation concentrate, aspirated dust, and middlings are blended to result in the sellable products metallurgical and steam coal.

Jan 1, 1984

By H. Sevim

This paper summarizes the research effort in simulating the operation of "Underground Coarse-Coal Hydrotransport Systems" (UCCHS). The equipment of the system to be simulated is already optimally selected by using an analytical optimization model. The purpose of the simulation model is to test the performance of the system and to obtain the distributions of operating parameters such as water and power consumption and amount of slurry delivered to the preparation plant. Knowledge of the distributions of these parameters is essential for the efficient operation of the system.

Jan 1, 1987

By J. A. McKeown, B. M. Sanders, A. Dadgar, R. H. Sergent

This paper describes the leaching of gold with Geobrom® 3400 from a very rich (6.2 kg/tonne) black sand concentrate and its subsequent recovery by ion exchange resins and solvent extraction. The dissolution of gold from black sand ranged from 94 to 96%. Gold loadings and recoveries of nearly 100% were achieved by both ion exchange and solvent extraction methods. The kinetics and equilibrium of loading gold onto ion exchange resins and its elution from the resin were studied. The commercial ion exchange resins PAZ®- 4, DOVEX®- 21K, and Amberlite® XAD- 7, and Great Lakes Chemical experimental GLR-30 were evaluated in this work. Diethylene glycol dibutyl ether was used in all the solvent extraction work for gold recovery from Geobrom leach solution. The consumption of Geobrom was about 130 kg per tonne of the concentrate processed. Therefore, the cost of lixiviant to extract 3.11 x l0-2 kg of gold from the black sand was only about $1.00. Based on the electrochemical regeneration of bromine, the economics of bromine process vs. cyanidation were investigated.

Jan 1, 1990

By H. Lyn Bourne

This is the 10th annual tabulation of US mineral royalties published in MINING ENGINEERING. The first year, 1982, the author solicited information about royalties and the cost of reserves. That column contained only a few royalties - not enough to tabulate. Since then, the response has been sporadic but the entries have grown to more than 300. Some have been deleted. Some of the older information has been deleted to make room for new entries. All indications suggest that the readers enjoy and use the information. But more information is needed. Russian practice In 1989, this column gave a brief history of mineral leasing and royalty payments as the concept applies to mining in the United States. This year&apos;s narrative deals with information about the mineral ownership in Russia. That country is in political and economic turmoil, including administrative systems and methods. And many laws are likely to change. What follows describes the Russian system of mineral ownership as of early 1992, according to Kirill Kavun. He begins "All the subsurface space of the Russian Federation with minerals contained belongs exclusively to the state. This forms the Common State Mineral Fund. Land parcels may be state, municipal, public or private property. They may be let to be owned and used by individuals, juridical persons, national/territorial or administrative/ territorial formations." This seems to apply to surface rights, as known in the US.

Jan 1, 1992

By F. Khorram

Image processing is a technique that simulates the human vision system. This technique enables applying every statistical or intelligent operation to recognize differences. In this way this new technique is used in quality control systems in most industries. Studying sedimentary rocks is very important from the economic point of view. Some units of sedimentary sequences involve different mineral deposits, hydrocarbon and water resources. Therefore it is important to identify and classify different sedimentary rocks. Descriptive classification of sedimentary rocks is usually based on visual and textural features and chemical composition of a sample. In this paper different samples of a limestone mine in central part of Iran are classified. The samples were collected from different parts of the mine and crushed down in size from 2.58 cm to 3.58 cm. The rock samples were labeled based on percentage of chemical and lithological compositions. Each sample was assigned to one of the distinguished groups. The images of the samples were taken in appropriate environment and processed. A total of 74 features were extracted from the identified rock samples in all images. In order to feature dimensional decrease, principal component analysis method was used. Then Bayesian statistical algorithm was used as a useful tool for classification. Classification Correctness Rate (CCR), calculated for the test data sets are %88, %68, %61 and %72 for the first to fourth class respectively. Therefore it can be inferred that the extracted features of images are appropriate indicators for different samples identification. These precise results besides the advantages of image processing technique, which are increasing speed of operation and decreasing cost, appears to be a desirable success.

Jan 1, 2012

The trend for using larger equipment in open pit mining to achieve cost effectiveness raises the question about the optimum economic point of scale in the current world of globalization. The present paper treats this question through the prism of a new methodology of assessing the impact of the size of production equipment on the economic outcomes of coal mining ventures. The methodology incorporates a production scheduling optimization model that implements both principles of mine planning, coal quality optimization and waste deferment. The implementation of the waste deferment principle dealing with the spatial and time aspects of the mine sequence arrangement allows the adequate modeling of the optimality of production equipment scale through the use of mine investment parameters, such as, purchase and ownership costs and discounted cash flows analysis. A case study is provided to illustrate the applicability of the new methodology.

Jan 1, 2004

By R. L. Miller

Two samples of iron enriched basalt (IEB) containing simulated nuclear fuel and having two distinct microstructures were prepared and tested for uranium recovery. The IEBs are refractory towards leaching by ground water. However, the uranium content (15.8%) is high enough that if aggressive leaching techniques are used for uranium recovery, these materials could be considered as man-made uranium ores. The IEBs discussed in this report were prepared to simulate Three Mile Island-2 core debris. The crushed IEBs were treated using three different methods simulating potential industrial scale processes. In one method the IEBs were fused with sodium hydroxide then the cooled mass leached first with water then with dilute sulfuric acid; about 52% of the uranium was recovered in this case. In the second method the IEBs were treated with a sulfuric acid/hydrogen peroxide lixiviant and about 13% of the uranium was recovered. In the third technique the IEBs were leached with a sodium carbonate/sodium bicarbonate/hydrogen peroxide solution. Only about 0.1% of the uranium was recovered. The results of these screening tests suggest that the IEBs can be successfully treated for recovery of the contained uranium. Other studies would be required to determine if other values, such as zirconium or silver, could be recovered from the IEBs.

Jan 1, 1984

By W. Kennedy Gauger, Tim Oolman, Debra L. Bisson

Radian Corporation (Radian) has developed a process for treating Cr(V1)-contaminated soils that involves: 1) soil washing using an alkaline extractant, 2) biological reduction of Cr(V1) to Cr(II1) in the soil wash effluent, and 3) separation of Cr(II1) from the biologically treated effluent. Biological treatment has been demonstrated for immobilized cells in fluidized bed bioreactors and suspended cells in slurry bioreactors for Cr(V1) levels ranging from 30 to 600 mg/L which have been reduced to non-detectable levels (< 0.05 mg/L; method detection limit [MDL]) during hydraulic residence times as short as 12 hours. The resulting Cr(II1)-containing effluent stream was chemically treated to precipitate chromium hydroxide for removal by physical separation.

Jan 1, 1995

By S. Borner Schweizer

An overview over SAM’s approach to assess corporate sustainability performance illustrates how sustainability challenges are linked to trends, assessment criteria and finally company performance. This process is exemplified with some general and industry specific criteria. Lastly, results of the Dow Jones Sustainability Assessment 2004 show a considerable gap between leading and average companies. Best practice examples demonstrate how lagging companies could improve their sustainability performance.

Jan 1, 2005

By G. W. Leney

Introduction and Historical Background The office and mining operations of Pacific Asbestos Corporation are located near Copperopolis, California in the foothills of the Sierras about fifty miles east of Stockton. This is historic country in the heart of the old Mother Lode gold district. Mark Twain&apos;s famous story of the jumping frog, written here, is still commemorated in an annual contest in Calaveras County,&apos; and the camp at Poker Flats, described by Bret Harte, was only a few miles from the present mine.2 Joaquin Murrieta, the famous Mexican bandit started his three year reign of terror in this vicinity,3 and Black Bart, the P08 laureate of the stagecoach robbers, held up his first stage at Funk Hill, just three miles north of the mine. His last robbery was at almost the place, on the top of the hill overlooking the Stanislaus River ferry crossing. Although this was his favorite country, and he traveled extensively through it, he was not a credit to his acclaimed profession of Mining Engineer because there is no evidence that he ever recognized the asbestos, and he was finally caught as a consequence of the robbery at the ferry.4 One of the old stagecoach roads crossed the Stanislaus River at the mine site, and the ferry landing may still be seen from the main haul road into the pit. The road itself is partly buried under the rock dumps. In spite of its location and apparently prominent exposure, the first work on the asbestos deposit was not recorded until 1904.5 Development of the present operations was started in 1959 by Jefferson Lake Asbestos Corporation, a subsidiary of Jefferson Lake Sulphur Company. Management control of the company changed hands several times and it was later reorganized under the name of Pacific Asbestos Corporation. In December, 1968, a controlling interest was acquired by H. K. Porter Company, Inc. Figure (1) shows the mill and office buildings as seen from a site near the entry road. The offices are at the left with the mill warehouse in the foreground. The conveyor at left center carrys mine concentrates up the hill from the crusher. In the background are the dry rock storage building and mill tailings piles. Since the beginning of mining operations in 1962, seven and three-quarter million tons of ore and fifteen million tons of waste have been removed from the open pit which now measures about 1400 x 1800 feet at its widest points. The lowest operating level is at an elevation of 726 feet about 325 feet below the original surface. Figure (2) shows the open pit looking toward the west end. The main haul road can be seen along the side of the pit. A shovel is operating at the bottom of the pit while a front end loader on the level above provides ore for blending. In the background are rock dumps for waste stripping. The company markets an annual production of 30-35,000 tons of chrysotile fibre in groups 4 through 7, under the Mother Lode Brand

Jan 1, 1972

By M. Pope

By 1950, packaged oil and gas fired boilers were on the market for capacities up to 30,000 lbs./hr. By 1962, capacities were up to 100,000 lbs./hr. and even higher when separate heat traps (economizers and air preheaters) were attached to the boiler packages. During this period, complete packaged coal fired boilers were developed into the 10-15,000 lbs./hr. range. Oil and gas fired plant designs became very compact, "basementless", and far: less costly than the coal fired plants of any capacity. Coal fired plants remained large and expensive, required field erection of boilers and required basements. With the spectacular strides made in automation, oil and gas plants became far less costly to operate, requiring only the part-time attendance of a single operator. Some advances were made in coal fired plants, but not to the degree attained by the fluid fuel competition.

Jan 1, 1965

By Norm Steenson

Rapid excavation includes rapid support and is the central theme of this paper. Over the last few years, enormous strides forward have been made in the excavation and material handling aspects of underground excavation. However, the technology necessary to support these rapidly created openings has lagged behind the other aspects. This paper would attempt to bring you up-to-date on the progress made in bringing ground support using shotcrete into the same productivity rates as the other cyclic operations. Shotcrete has become an acceptable material for temporary and permanent support for undergound openings. However, coarse aggregate shotcrete has been an expensive construction material. It has been confined in the main to difficult ground conditions where conventional methods of support have proved to be even slower and more expensive than shotcrete. There are two main factors influencing the productivity of shotcrete equipment. (1) Structural shotcrete as opposed to gunite requires 40% to 45% rock minus 3/4" in the mix design. The equipment to handle such aggregate content has been difficult to develop on a volume basis owing to the attritional nature of the material which causes intense wear problems on

Jan 1, 1974

By Sadatoshi Ohmori, Karen Shinoda, Nobuharu Isago

Method of tunnel excavation is generally classified such as full-face excavation, bench-cut excavation, diaphragm with center pillar excavation, center drift advancing excavation and so on. These excavation methods should be selected properly in terms of ground condition, the area of tunnel section, the arrangement of construction. Center drift advancing excavation method in mountain tunnel construction, is often applied under quite weak ground condition, prior to the main tunnel widening excavation. Recently, the advancing drift is for the excavation of extreme larger section in main tunnel to confirm the stability of face. In addition, we make advancing deformation occur in drift when the construction was done in poor ground like squeezing and swelling ground, and the force occurred in main tunnel was expected to reduce by the effect of ‘dodging’ for support structure. Mechanical relation between drift and main tunnel has been mainly grasped on past experiences in Japan. However, the characteristic of tunnel enlargement was partially discussed by using the three dimensional analysis and the result was grasped by past experiences on the basis of each tunnel construction. It is considered that the natural ground stress is normally released as the advance displacement, but it was released after the main tunnel widening, causing a displacement and deformation increase. Up to now, the construction practice has shown the reduced displacement during the main tunnel widening excavation by the drift, and the numerical analysis agreed with above observation. However, there is no report found that the displacement and deformation at the time of widening excavation of the main tunnel become larger in case of a drift application. In Kyusyu area, western part of Japan, the northern part of Yoshinomoto tunnel was applied an advancing bench-cutting method for a center drift for the purpose of obtaining the geological information for support selection of the main tunnel in widening excavation. The shape of center drift was a perfect circle with a diameter of 4.0 m or 6.0 m and the same temporary support regardless of the geological situation. As a result, the displacement and deformation of the main tunnel after widening excavation were larger than the section where the center drift was not applied. Furthermore, the displacement and deformation of the main tunnel after its widening excavation was considered larger in the section where the cross-section of the center drift with 4.0 m diameter was applied than one with 6.0 m. Therefore, the center drift with a high rigidity support structure had the effect of suppressing the advancing deformation prior to the main tunnel widening excavation.

Jun 13, 2021

By M. Mankosa, G. Taylor, G. Luttrell, J. Yasalonis

Several industrial-scale HydroFloat separators have recently been installed at Mosaic’s South Fort Meade beneficiation plant for the purpose of improving phosphate recovery and throughput capacity. This technology was implemented after numerous laboratory, bench-scale, and on-site, pilot-scale test campaigns. The results from this detailed test work provided sufficient justification for the complete retrofit of the existing coarse and ultra-coarse flotation cells. Data indicate that the metallurgical results obtained with the full-scale separators are consistent with that obtained during both the bench- and pilot-scale evaluations. The apparent benefits, theory of operation, and commissioning of the equipment are also discussed.

Jan 1, 2007

By D. J. McParland

This paper will deal with some of the considerations which, were involved in the design and construction of the uranium mills in the Elliot Lake area . These plants, eleven in number, range from 1500 to 6500 tons per day milling capacity. Most references are with respect to the seven plants in the Rio Tinto Group which have a combined milling capacity in excess of 20,000 tons per day. In dealing with such abroad subject as mill design, one has the choice, of covering a few specific problems in great detail, or else attempting to cover many subjects superficially and briefly. In preparing this presentation, an attempt has been made to compromise on these extremes, and to select some interesting illustrations which are of general interest in the field of mill design, and of value to persons concerned with mill design broadly, beyond the field of uranium mills.

Jan 1, 1959