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By John A. Sievert

Sedimentary deposits contain an appreciable portion of the world's supply of uranium. Predictions of nuclear fuel usage in the United States indicate that these reserves will have to be tapped if the domestic industry is to be the major supplier of fuels for the nuclear reactors. Techniques developed within the petroleum industry are a base on which to build economically attractive fluid mining processes for the recovery of these uranium values. The problems central to the success of such mining processes are the containment, control, and recovery of a narrow band of pregnant leach solution as it progresses from the point of injection to the point of production Given sufficient incentive, suitable solutions to these problems can be found

Jan 1, 1970

By Ronald R. Hartman

I can recall a time 10 or 12 years ago when I spent a pleasant Sunday afternoon driving to Jim Thorpe, Pennsylvania to see a carnotite deposit that had recently been discovered. The announcement of the discovery stated that it was in the Pottsville conglomerate in a road cut along the highway. To my surprise, the highway was lined with cars and every weekend prospector for 100 miles had come to see the ?big uranium deposit of the east?. I literally had to stand in line to make a measurement with the scintillation counter I had with me. The thought at first occurred to me that this is evidence of how thoroughly the surface of the United States must have been prospected, more likely, perhaps it points out quite the opposite. A lot of time and energy was being spent in tracing the footsteps of others and a lot of time was spent looking for the obvious occurrences. The point is, that in the early days a tremendous amount of uranium exploration was carried out but few systematic surveys were made. Thorium anomalies were usually discounted after cursory surface field checks. Conversely, in airborne surveys - anomalies due to elevation changes or thin over- burden on hilltops were often investigated more thoroughly than smaller indications on hillsides and valleys. An adequate supply of uranium was nevertheless found due to the ingenuity and persistence of the geological profession and the public in general. This ?adequate? supply, like so many estimates for raw materials turned out to be far too low.

Jan 1, 1967

By P. Worley

Installation of UP& Is monitoring system was planned to be completed in three stages: Environmental Monitoring, ConveyorBelt Interface, and Power Distribution Interface. With Phases 1 and 2 completed and Phase 3 initiated, massive amounts of valuable information have been obtained. From this information, many benefits where recognized and the decision was made to expand the system. This provided monitoring and control capabilities in a variety of new applications from ventilation fan and pump interface to innovative installations such as ground control monitoring. All current uses as well as future plans for expansion and data manipulation will be discussed.

Jan 1, 1990

By M. A. S. Martins, H. Medeiros, B. Y. B. Dos Santos

This paper contains the geometallurgical studies, performed for Mineração Rio do Norte bauxites, applied to a selected area belonging to Plateau Saracá III, referring to an exploitation period of one year and three months, approximately. It is worth mentioning that Mineração Rio do Norte has the biggest bauxite operation in Brazil producing 8,500,000 tons of concentrate per year. The studies included wide investigations directed to the final objective of establishing a precise mining and production planning, based on the different behavior of the distinct bauxite ores, when submitted to industrial processes. Geometallurgy can be defined as the study of the regionalization (space distribution) of the metallurgical variables of a mineral deposit. This study involves and integrates all process engineering, geology, geostatistics and mining planning, among others. The development and application of the geometallugical studies to Mineração Rio do Norte were motivated by several reasons and necessities, among them: 1. Improving the forecast of the amount of concentrate (metallurgical mass yield) produced; 2. Improving the equipment operational efficiency, providing a more homogeneous feed; 3. Conducting a more precise material balance that permits a better daily, monthly and yearly production control; 4. Improving the forecasts for the final products generated by each ore type; 5. Obtaining better knowledge of the behavior of several ore types, submitted to the different process unit operations; 6. Promoting adequate ore blending, producing an homogeneous feed during mining operation.

Jan 1, 1998

By Dermot M. Ross-Brown

The more important factors controlling the design of pit slopes are related to the local geology over which the designer has little or no control. Nevertheless, there are some factors over which the designer does exert some control and these concern the say in which the rock is excavated and supported. They include blasting, face cleaning, water control, and the use of rock improvement techniques. The paper discusses these factors and relates the extra costs incurred to the steeper slope angles that can usually be obtained. It is demonstrated that even a modest increase in bench angle of 5° through improved excavation techniques can pay off in a single push-back.

Jan 1, 1975

By J. S. Hayden

It is becoming increasingly difficult to secure local aggregate resources that meet quality standards and local restrictions without conflicts with other land uses and environmental regulations. The successful integration of natural-resource information into land-use decisions is becoming increasingly important as the needs for both land and resources become more numerous, complex and urgent. Well-reasoned decisions about land-use are crucial to the Nation if infrastructure resources are to remain economically available. Provisions for uninterrupted future supplies of aggregate should be made using proper long-range planning that incorporate a multiple land-use program. That program would include identification and protection of natural resources, strategies that will permit development of resources according to future market needs and environmental considerations, and the beneficial reclamation of mined-out areas.

Jan 1, 1997

By-products are of greater importance in lead and zinc mining than in any of the other major base metals. While I think most mining people would accept that statement, you would probably get some widely varying estimates when attempting to quantify the value of by-products in lead and zinc mining. We are now able to do this with our lead-zinc mine cost model. This model was originally developed as a zinc mine cost model to help us forecast long-term zinc supply and price as part of a study we completed in late 1979 entitled "Zinc - The Next Decade". Before demonstrating the importance of by-product revenue to lead- zinc mines, let me first explain how the cost model was constructed. I will discuss the model as it was originally constructed - as a zinc mine cost model. It has subsequently been expanded to include lead only mines and now can Be run either as a zinc or a lead mine cost model.

Jan 1, 1980

By Osvaldo A. Bascur, J. P. Kennedy

Companies have installed powerful desktops for their personnel and instrumentation and control systems in their plants. These desktops are, in many cases, connected to a company intranet. Still, process engineers have to obtain their data manually. Engineers use process calculations from manually calculated averages from the plant; field operators collect equipment data on log sheets; and maintenance engineers collect critical information on log sheets. All of this information resides in individual machines. What are the strategic tools that will enable collaboration between them? How can operators, engineers, and managers access plant information to proactively increase their effectiveness in process troubleshooting, plant debottleneclung, aligning with business strategic and customer demand, satisfying environmental and safety regulations, developing capital projects, and implementing control strategies? A nonintrusive environment at the desktop is required to provide the process information to these workers. How can value be added to MS Windows technologies with the legacy systems at a minimum cost? There is no straight answer; however, there is a proven framework to leverage the large investments in new technologies. Objects and components are changing the way everyone relates to their computer and networks. Three examples will be described to demonstrate paradigm change. Today, process engineers can access data at the required level of detail for analysis of critical process variables at their desk or remotely. 1. Process Troubleshooting and Analysis: The engineer can develop an inferential calculation, trigger a process advisor to deter- mine the behavior of the units for the last day, and get the population of a set of batches (heats, blocks, rolls, sheets, etc). 2. Process Control and Optimization: The engineer can connect to a process simulator at steady state or a dynamic simulator of the process to evaluate new control strategies or process unit line-ups and use the process simulator as a process observer for fault diagnosis. 3. Collaboration with Accounting and Maintenance: The engineer can review reconciled data and the process mass balances, suggest maintenance cleaning or recalibration of flowmeters, and evaluate key control performance of all advanced controls.

Jan 1, 1999

By Kenneth A. Grace

Each and every mining operation from a simple sand-and-gravel pit to the largest integrated mine-mill-concentrator-smelter-refining complex has, as its foundation, a quantity of extractable natural resource the reserves. Without reserves, there is no mine, and any concentrating or extracting plant, no matter how sophisticated, is simply so much scrap metal. And, of course, without resources there are no reserves. It is remarkable, therefore, especially in this age of careful planning, high quality engineering, and state-of-the-art financial analysis, that such a fundamental and vital item is so little understood and the subject- of so much confusion. Time and time again it has been the experience of the author, when called in to a mining operation that has run into trouble in reaching projected production targets, to find that the designed-for tons were not reaching the concentrator/extraction plant, and/or the grade of such tonnage was substantially below the forecast and design grade of the plant. The mill blames the mine for delivering below standard tons and/or grade and the mining engineer blames the geologist for overly-optimistic assessment or incorrect interpretation of the deposit. The geologist blames the mining and metallurgy division for wrongly interpreting his data and conclusions, or simply fouling-up a fine orebody.

Jan 1, 1983

By William J. Taylor

Strictly defined, a stull is an inclined or horizontal timber support; a vertically placed timber is defined as a prop. Common usage allows the catchall term "stull" to refer to all such uniaxial mine support, regardless of orientation. Typically a stull is a round wooden column that is wedged in place to provide short-term auxiliary support between sill and back, or between hanging wall and footwall. Stulls may be used exclusively or in con- junction with other support systems such as roof bolts, shotcrete, or cribbing. Stulls are used both as local temporary support in stoping operations and for uniform systematic support installations. Where stoping areas are to be abandoned soon after excavation, stulls may be used to provide temporary support during mining operations. Where controlled caving and subsidence is required, stull supports are designed to fail in a systematic, predictable manner. Wood type is selected on the basis of availability, price, and load carrying characteristics. Coniferous woods are typically used, especially to carry heavy ground loads. Brittle woods are generally avoided because of their tendency to fail suddenly. Gradual yielding failure is preferable to sudden, unexpected failure of the support. Some usage of wood from deciduous trees such as cottonwood and other poplars has been reported in Grants, NM. These stulls reportedly mushroomed as the ground load increased but continued to maintain their structural integrity. Stulls fabricated from structural steel are used in special applications. Adjustable lengths are commercially available in mechanical, hydraulic, and pneumatic designs. The high cost of mechanical stulls limits their use to mining systems where recovery and reuse is possible. End blocking, also called headboards or footboards, uses wood blocks that are placed between the stull end and the ground they are supporting. The blocks are typically 50.8 to 101.6 mm (2 to 4 in.) thick, 203.2 to 304.8 mm (8 to 12 in.) wide, and 381 to 609.6 mm (15 to 24 in.) long. End blocking serves to distribute the support over wider back area. Compression of the end blocking gives visual indication of wall movement prior to failure of the stull. A common application of the stull is in flat-bedded uranium mining during pillar extraction. Many western US uranium mines use a pillar pattern development to delineate the irregular ore pods. After development of an appropriate sized pillar, the ore pillars are then sequentially mined out, leaving the undercut hanging wall or back to cave. Where thickness of the ore is less than 4.3 m (14 ft), stulls are generally used to provide ground control as the pillar is removed in slices. Experience dictates the density of stull placement. In general, the number and size of stulls should be sufficient to resist ground closure and to provide support for drilling and loading operations adjacent to the pillar. Stulls next to the mining face are often lagged 0.9 to 1.2 m (3 or 4 ft) up from the floor (or sill) to confine the blasted ore to a passage next to the pillar. Mucking is simplified by this confinement. Experience dictates whether back control along a mining face requires removal of stulls to allow con- trolled subsidence of the back or hanging wall. Without caving or closure, abutment pressure can create poor ground conditions near the pillar.

Jan 1, 1982

By T. A. McAfoose

As one of the major suppliers of the chestnut Ridge energy center, Rochester and Pittsburgh Coal Company continues the search for more efficient haulage systems. This search is one that is essential in providing coal to the Keystone and Homer City power plants at the most economical cost. These two electrical generating plants located in west central Pennsylvania are part of the energy center which consists of four generating stations. Prior to the time the two stations were put on line, August, 1967 for Keystone and August, 1969 for Homer City, our company made the decision to rely on belt conveyors from the section to the surface to provide for continuous main line haulage. The proximity of these generating stations to proven reserves allow for minimal truck haulage and minemouth setups. With the addition of seven new mines, in the past ten years, revisions have been made on the original setup to interconnect the haulage of several mines to deliver the product by belt to the power plants.

Jan 1, 1979

By Jack O?Hearn

A liquid and solid waste management plan for an operating uranium ore processing mill was developed to efficiently and effectively dispose of existing solid wastes and related, affected surface and ground water resources. The goal of this management plan was to achieve satisfactory clean up of these existing wastes ad their by-products as well as to prevent similar situations from occurring in the future. An existing, modern system of synthetically lined tailings ponds, constructed after many years of mill operations, now provides an approved site for the disposal and containment of waste streams currently generated by the mill. This system was thought to be readily adaptable to serve as a key element of the waste management plan. The potential presence of extra capacity in these ponds could eliminate or reduce expenditures for new facilities required solely for proper management of liquid and solid wastes generated by operations prior to construction of the modern tailings ponds as well as for a range of anticipated future operations.

Jan 1, 1984

By Larry Diaz

A single stage ball mill-cyclone circuit was extensively tested for its reactions to step changes in three controllable variables: feed rate, water to cyclones, and water to the ball mill. A series of carefully designed tests are to be carried out in order to determine relationships between the various ball mill and cyclone parameters. Cyclone overflow particle size distribution is to be continuously monitored during the tests using an ultrasonic device. Other circuit variables that are to be measured and recorded are feed rate, ball mill mass flow, cyclone feed and overflow densities, cyclone feed sump level, water flows, etc. Once the circuit performance is defined, two types of grinding circuit control systems will be evaluated: (a) mass flow-based; (b) particle size- based. Results obtained by each approach in terms of feed rate and cyclone overflow size distributions are discussed. The high sensitivity of continuous particle size measurements to grinding circuit disturbances is emphasized.

Jan 1, 1971

By Joseph F. Shirley

A froth flotation plant to recover by-product molybdenite must be designed specifically for the selected separation process and the type of ore being treated. However, some general rules concerning by-product molybdenite plant design can be suggested that would be valid for most processes. The term by-product molybdenite in this paper is limited to the recovery of molybdenite from copper porphyry ores, which essentially amounts to selectively separating molybdenite from copper and iron sulfide concentrates. In addition, most of the discussions would apply only to the almost universally used approach of floating the molybdenite and depressing the copper and iron sulfide minerals.

Jan 1, 1979

By S. C. Sun

Very little information is available concerning the magnetic properties of minerals and only recently has there been any attempt to correlate magnetic susceptibility with varying chemical composition1. The work described here covers a study of the relationship and chemical composition of both the rutile and sphene types of titanium minerals. The relationship between the magnetic susceptibility of three selected mineral specimens and the applied field strength is also presented. Experimental: The equipment and procedures used in this in- vestigation for crushing and cleaning the mineral specimens and for determining the magnetic susceptibilities were the same as that employed by Spokes and Mitchell1. The particle size of-the measured specimens was limited to 270/325 mesh.

Jan 1, 1959

By Carl Heising

Longwall workings in the Federal Republic of Germany are situated in deep depths. Coal deposits are characterized by a sequence of many seams and manifold geological disturbances. Hence result special requirements on the layout of workings, the methods of coal getting, supports, mine ventilation and dust control. As for the application of dust control the large quantities of fresh air and, this, the high air velocity and the limited water contents in the run-of--mine coal must be taken into consideration. The principle of our methods of dust control is to avoid, if at all possible, the development of dust and, if this is not possible, to suppress the dust even during its development. In nearly all coal faces, the method of water infusion prescribed by our Mines Inspectorates is applied. Continuous water in- fusion is preferred. For water infusion in the coal face, intensive developments as to the process and as to the tools and apparates to be applied were done. The German coal mining industry differs between cutting coal getting and stripping coal getting. Water spraying to the tracks of coal ploughs as well as internal and external water feed to the loader required special activities of further development in past years. There are possibilities to still improve such methods in future. A new important field of applying dust control developed from the application of powered supports. In this field, water spraying prevails. Wet methods of dust control are prefered also in the conveying and loading of coal and at through-flow crushers, however, as far as possible, combined with a covering of the working points where dust develops. Devices for the collection and sedimentation of dust, so-called dust exhausters, are used also with crushers In advanced headings, dust control is performed solely by water. Gateroads kept on or behind the coal face line call for new methods of dust control which are at present under development.

Jan 1, 1980

In spite of our deep conviction that it would be wrong for the United States to enter World War II, when, after Pearl Harbor, we were actually in it, I felt that I must do all I could to help. The country had been so good to me that I could not decently stay on the sidelines. My first thought was that I might help with supply and administration in the Air Force, as in World War I. So on the evening of Pearl Harbor I wired the chief of our Air Force in Washington saying that I had been on Gen. William Mitchell's staff in World War I and was offering my services again. I received a noncommital answer, but after a couple of weeks was told to take my physical examination. I passed it, but nothing further happened. After helping to make plans for the wartime operations of Summit King and Desert Silver, Dorothy and I went to New York to spend Christmas with Molly and Peter, both of whom were in college in the East. I had to complete a report on the Argonaut mine in California first, though the war made my recommendations of dubious validity. Before Christmas I received wires from Temple Bridgeman, Phil Wilson, and other friends who had taken positions with government agencies responsible for securing mineral products needed for war use. They urged me to join them. It was evidently a case of not whether but how I could be most useful. After six uncertain days with the family in New York I took the night train to Washington on the 28th of December. I had a hectic day there. First I saw Arthur Bunker and Phil Wilson at what became the Aluminum and Magnesium Division of the War Production Board. Their office was in an old converted barracks. They asked me to examine magnesium deposits in Nevada at once, and then to look at other magnesium and aluminum properties. After leaving

Jan 1, 1976

By S. E. Restrepo

To innovate and make the operation sustainable it is necessary to identify the externalities and impacts completely. This paper presents the results of a proposed methodology to make circular economy initiatives viable in mining operations using these aspects: • Economic, safety, and environmental (HSE) risk analysis • Technology observation • Mineralogical characterization • Identification of potential waste uses • Use of government economic benefits The results of the project can be summarized as follows: • Implementation of new technologies in the aggregates process, • efficient use of water, • the valorization of waste to convert it into a by-product, • and access to tax benefits for investment savings.

Mar 2, 2022

By Thomas B. Borak, Keith J. Schiager, Janet A. Johnson

INTRODUCTION Several major factors introduce uncertainties into the assessment of radon progeny exposure to miners using time-weighted average radon progeny concentrations: uncertainty in the measurement of radon progeny concentrations in specific areas, assignment of an individual miner's time to those areas, variation in radon progeny concentration between measurements and potential human errors involved in calculating concentrations and handling data. The currently available grab-sampling methods for determining working level were analyzed to determine the magnitude of the uncertainty due to each of these factors. For all measurement methods studied, the variation in the airborne concentration with time in operational areas of a mine is the dominant factor in the uncertainty in determining annual radon progeny exposures for individual miners. Uncertainties relating to accuracy of the method and precision of measurement were found to contribute a significantly greater portion of the total uncertainty than human errors. Under normal conditions, if the technicians performing the measurements are conscientious and well trained, human error contributes little to the total uncertainty of the radon progeny exposure determination. The primary goal of radiation monitoring is the reduction of radiation exposure to the lowest reasonably achievable level below regulatory limits. Monitoring personnel in mines should be trained not only to obtain accurate estimates of miner radiation exposures but also to recognize and, when possible, to implement correction of situations which result in unnecessarily high radon progeny exposures. ESTIMATION OF UNCERTAINTY DUE TO HUMAN ERRORS Human errors affecting the assignment of annual radon progeny exposure to individual miners can be placed in two categories: those related to the measurement of radon progeny concentration in specific mine areas and those related to estimation of occupancy time for individual miners and transcribing data to permanent records. The former are specific for the measurement method used; the latter are common to all methods. Errors in Determination of Working Level All systems for determining radon progeny concentration require measurement of several parameters, which include volume of air sampled, count rate and decay time. These quantities and appropriate constants are used in a basic equation, specific to the system, which estimates working level. An unintentional random mistake in measurement of any one of these parameters or in the selection of proper constants will contribute to the uncertainty in the determination of working level. In our analysis of human error we separated each measurement method into a sequence of independent operations, with each step subject to operator error. For each operation we estimated the probability of occurrence and the consequence of errors to obtain a resulting uncertainty. Certain types of errors result in specific consequences. For example, we assumed that an error of 5 seconds in timing of a 5-minute sample results in a fractional error of 1/60 (1.7%). Other types of errors can result in a range of uncertainty. Transposing digits read from a scaler can produce errors ranging from near zero to approximately 60%. In these cases we calculated the statistical variance for the distribution of errors. We assigned the square root of the variance divided by the mean as the consequence factor for that type of error. This is essentially the same as a coefficient of variation. The product of the probability of occurrence and the consequence factor is the fractional uncertainty in the measurement due to that particular error. The total uncertainty due to human errors is calculated by taking the square root of the sum of the squares of the uncertainties generated by all manual operations. Uncertainties Due to Human Error for the Kusnetz Method One of the techniques most commonly used to estimate working level in U.S. uranium mines is the Kusnetz method. A generalized way to express the equation used to compute WL by this method is: WL = (Net Alpha Counts)/(V)(ST)(CT)(E)(K) where: V = sample flow rate in liters/min ST = sampling time in min CT = counting time in minutes E = absolute counting efficiency K = Kusnetz conversion factor (dis/min-L per WL), as a function of decay time in minutes. The example of human error analysis presented here is based on the Kusnetz procedure having a timing sequence of 5 minutes sampling time, 40 minute decay time, 2 minute counting time. During the sampling procedure a stop watch is used to determine the timing interval. We assume that it is common to make small timing errors of a few seconds, but larger timing errors occur infrequently. Errors greater than 30 seconds are considered to be essentially non-existent since we assume that the

Jan 1, 1981

By C. D. Litton

This paper describes two new gas diagnostic techniques which have been used successfully to determine: 1) the combustion status of underground mines which have been sealed due to fire (Littol1 Ratio); and 2) the location of fires in abandoned, underground mines or waste banks (Kim Ratio). The Litton Ratio makes use of the rate of change of CO, calculated on both an air-free and methane-free basis, from mine gas samples and compares these values with those expected from a normal, combustion-free environment. The Kim Ratio uses the concentrations of total hydrocarbons, C2 ?C5, less the methane, to arrive at ratio values which increase as combustion intensity increases. The details of these two new techniques, their application to real situations, and their limitations will be discussed.

Jan 1, 1989