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By Alissa Lockett, Chris D. Breeds

Central Water Integration Project (CWIP) Segment 5-1 is the most critical segment of a regional water supply project that transfers groundwater from Burleson County to northern San Antonio, replacing over 20% of that City’s water supply with a new source. CWIP Segment 5-1 included three tunnel reaches totaling 10,350-ft and 5 shafts that were constructed inside the City in an area known to contain large karst features. This paper describes site work used to investigate the alignment for karst features, manage potential environmental impacts, develop the contract package required for mitigation and the means and methods used to mitigate the large karst features that were encountered.

Dec 1, 2022

By D. N. Madge

A survey is given of production scheduling systems currently in use or contemplated for future use in Cominco operations. Emphasis in this presentation is made on the chain of decisions that are made with the help of mathematical programming models. Some attention is devoted to the structural properties of the models.

Jan 1, 1966

By R. V. Ramani, K. V. K. Prasad, M. Swaminathan

Engineering design involves, in addition to numerical calculations, considerable amount of expertise and judgement. The expertise and judgement is required to conceptualize and idealize the problem, select a suitable mathematical model for the problem and to interpret the model results in terms of stipulated design constraints. In recent years, knowledge based systems (KBS) have provided the capability to integrate the qualitative experiential and expert knowledge with the quantitative knowledge for improved analysis and design of systems. A possible KBS architecture for mine ventilation system design was discussed by Ramani and Prasad (1987). The expert system (ES) component of the KBS supports the analysis and interpretation phases of the ventilation design process with an algorithmic program used for the solution of alternate designs. The purpose of this paper is to discuss the data and knowledge needs for developing such a system and a formal means of their representation on the computer. A number of ES shells were evaluated to explore possible development and delivery environments for the system. A brief summary of this evaluation is also provided.

Jan 1, 1989

By Sebastian Avalos, Julian M. Ortiz

The long-term mine scheduling is the optimal decision on how to extract and process the mining reserves. The resulting plan is mainly driven by economic, metallurgical, and geological factors. Accounting for their uncertainties leads to a robust solution and the feasibility for economic-risk quantification. In this work, we model the spatial uncertainty of grade distributions of multiple correlated elements, by using a multivariate morphing transformation. The result is a set of multivariate geostatistical realizations of the grades, which honor the conditioning data, the direct and cross variograms, and the multivariate statistical distribution, inferred from a set of samples. These models are the input in a reinforcement learning framework, adopted to train a deep neural network that considers the grade uncertainty and leads to an optimum mine plan after training using deep Q-Learning. Mining and processing capacities, as well as economic parameters and metallurgical constraints, are incorporated as the reinforcement learning environment rules. The method is validated on a real deposit, providing insights for future applications.

Jun 25, 2023

By R. H. Weiland

The dewatering of flocculated clay suspensions by compression in a centrifugal field has been investigated. The results are evaluated with regard to both direct applicability to centrifugal dewatering, in solid-bowl centrifuges for example, and indirect applications to gravity sedimentation systems. It is well known that sediment consolidation under gravity depends on structural characteristics such as permeability and on the "self-weight" of overlying sediment layers. An important objective of the study has been to evaluate the self-weight effect using centrifugal forces to simulate consolidation in deep sediments. In this way, small-scale laboratory tests can be used to predict the rates and limits of sediment compression in industrial systems such as thickeners and settling ponds. Experiments have been conducted in which the sediment mass and initial structure were maintained constant while the effective sediment weight was varied by centrifuging at different speeds. The effects of initial structure have also been studied using controlled variations in flocculation conditions.

Jan 1, 1993

By R. C. Berry

The Environmental Impact Statement (EIS) has become a routine requirement for mining operations on federal lands. A similar document is being required in developing countries. Baseline studies are needed prior to writing an EIS and these studies involve surface water, groundwater, air quality, and wildlife/ native plant evaluations. The required baseline hydrology and geochemical studies are often the most expensive and lengthy evaluations. This paper summarizes the hydrology and geochemical baseline studies required for .An EIS and presents suggested methods to expedite these studies and to shorten the time and the cost to complete the studies and the EIS.

Jan 1, 1999

By Willard A. Murray

Investigations of underground coal gasification (UCG) have been actively pursued by the U.S. Department of Energy since the early 1970s; the Lawrence Livermore National Laboratory (LLNL) conducted its first field experiment in 1976. In conjunction with field and laboratory studies of the process of recovering energy in the form of combustible gases from the burning of coal deposits in situ, an extensive environmental program has been conducted at LLNL under the auspices of both the U.S Department of Energy and the U.S. Environmental Protection Agency. This program has focused on groundwater contamination and ground surface subsidence caused by UCG. The material presented in this paper is a summary of results from the environmental studies of UCG activities conducted by LLNL as described by Mead, et al. (1981) and supplemented by the author's experience with this program in 1980 and 1981. The following sections describe specific groundwater contamination and surf ace subsidence problems encountered during field experiments in northeastern Wyoming, and will discuss implications of preliminary findings from geohydrological investigations of a site in southwestern Washington. Finally, possible environmental control technologies that are most likely to be effective in mitigating environmental impacts are discussed.

Jan 1, 1982

By Bruce R. Lipin

Chromite, the only ore of chromium, occurs almost exclusively in mafic-ultramafic rocks and their weathering products. However, not all kinds of mafic-ultramafic rocks are favorable hosts for possible low-grade chromite deposits. For instance, chromium-bearing basalts are not favorable because they commonly contain < 0.3% Cr2O3, and chromite is almost always less than 50 um in diameter, if it is present at all. Chromite-bearing ultramafic rocks in stratifonn and alpine complexes tend to be either ore grade (> 25% Cr203) or very low grade (< 2% Cr203); intermediate rocks are scarce. In most complexes large tonnages exist only in the < 2% Cr2O3 group and the composition of the chromite is commonly unsuitable for metallurgical use. Some nickel laterite districts contain more than 108 tons of material with 2.0% to 5.5% Cr2O3, and hence, chromium could be a byproduct of nickel in some laterite districts.

Jan 1, 1982

Operation of a pilot-scale Floatex density separator was studied using a pyrite concentrate slurry feed. Experimental measurements were further utilized in parameterization of a hindered settling simulation model. The model incorporates particle slip velocity calculation and also a separation efficiency function, adjusted to describe the feed material characteristics. The model was used to compute the overflow and underflow compositions when both fluidization bed pressure and teeter water flow rates were varied. In addition, prediction accuracy and the model validity were evaluated. The simulations gave good results when the teeter interstitial velocities were moderate enough to avoid excessive turbulence in the fluidization. Prediction of the cumulative overflow and underflow size distributions in most experiments yielded essentially less than 10% relative error between the sample data and the estimated value of the 50% passing sizes.

Jan 1, 2011

By Douglas Beahm

Energy Metals Corp. (EMC) holds numerous mineral properties in the northern portion of the Great Divide Basin. The JAB property is one of several potential properties being planned for development as a satellite facility to the greater Antelope uranium project. A National Instrument 43-101 Technical Report was completed for the JAB property. This report estimated total measured and indicated mineral resources on the property totaling 1.6 kt (3,555,022 lbs) U3O8 contained in 2.2 Mt (2.4 million st) at an average grade of 0.073 percent U3O8 at a 0.25 grade times thickness (GT) cutoff in accordance with CIM Standards on Mineral Resources and Reserves. The JAB property is located in Sections 13, 14, 15, 16, 21, 22 and 23, Township 26 North, Range 94 West, approximately Latitude 42° 14’ North and Longitude 108° 00’ West (Fig. 1). This property consists of unpatented mining lode claims and Wyoming state mineral leases com-prising approximately 850 hm2 (2,100 acres).

Jan 1, 2007

By Shuchen Sun, Ganfeng Tu, Chuan Liu, Xiaoping Zhu

The hydrometallurgical residue generated during the hydrometallurgical processing of waste automotive catalysts is valuable as a secondary resource. In this study, a process of platinum recovery from the hydrometallurgical residue by high-temperature smelting process was proposed. Results of lab- and pilot-scale experiments show a high recovery of more than 98% of platinum and glass slag was successfully obtained by controlling the Fe3O4 addition, C/Fe3O4 mass ratio, CaO/SiO2 mass ratio, smelting temperature, and holding time at 15 wt%, 0.4, 0.6, 1500 °C, and 120 or 60 min, respectively. Results from the pilot-scale show that the platinum contents in the glass slag and alloys were less than 4 g/t and more than 0.6 wt%, respectively. Therefore, the process proposed in this study is a prospective and effective approach for reutilization of hydrometallurgical residue containing platinum.

Oct 12, 2020

By Frank C. Schora

The Institute of Gas Technology for many years has dedicated a large portion of its research effort to the development of a practical solid-fuel-based gasification process to produce a synthetic natural gas equivalent. The work is being done to prepare for the day when supplemental gas will be needed. This program, initially supported by the American Gas Association, and now by both the Department of Interior&apos;s Office of Coal Research and the American Gas Association, has developed the IGT Hydrogasification Process. This process, now entering the pilot plant stage, is based on the high-temperature, high- pressure hydrogenation of coal with a hydrogen-steam bearing gas. Product gas from this step is cleaned and catalytically methanated to produce a high-Btu gas. Estimated production costs indicate the process will be competitive with natural gas in certain areas of the country when required.

Jan 1, 1969

By Marini David, Pigorini Andrea, Fuoco Stefano, Zurlo Raffaele

"The excavation of a tunnel in highly weathered and strongly fractured rock masses due to tectonic actions is still a challenge. In order to maintain reasonable productivity, excavation through a wide zone of highly tectonized rock mass requires a detailed, integrated study of the construction solutions and a monitoring system to minimize the process time and to optimize the adopted consolidation measures in accordance with a predefined matrix of possible support systems. This paper summarizes some interesting data acquired during the excavation of the Brenner Railway Base Tunnel system between Italy and Austria. The Brenner Base Tunnel (BBT) runs through the fault line between the European and the African tectonic plate. This big fault zone is called “Periadriatic Line.” In particular, data acquired in the exploratory-service tunnel have been analyzed. Furthermore, the base concepts for defining the consolidation and support solutions adopted for the excavation of the exploratory tunnel are described. INTRODUCTION The Brenner Railway Base Tunnel (BBT) is a system of underground structures and tunnels that is designed to connect Italy and Austria using new railway standards. It is based on high speed (HS) concepts and applies the European Standards for Interoperability (TSI). The railway includes twin tunnels for a total length of about 55.0 Km without considering the connection tunnels to the existing underground railway in Innsbruck. Including the latter, the total length of the tunnel system reaches 64 Km, and is among the longest tunnels in the world. The Italian section passes through the so-called ""Periadriatic Line,"" which is an important tectonic structure generated by the collision between the European and the African tectonic plates. Despite the extensive investigations carried out (boreholes down to 700 meter depth), significant geological and mechanical uncertainties inside the Periadriatic formations remained unsolved. In order to elevate the level of confidence and observe the behavior of the rock mass at a representative scale, the BBT Authority decided to excavate in advance the service tunnel, which has taken the function of an exploratory tunnel. The data and observations collected during its excavation would provide important insights for the design of the main tunnels."

Jan 1, 2016

Federal regulations require the use of methane monitors on all mining machines. All machine-mounted methane monitors currently used in underground coal mines rely on catalytic heat of combustion sensors. As a comparison, although not currently approved for use on underground mining equipment, instruments with infrared sensors are evaluated in this study. Potential advantages of using infrared sensors include faster response time, long-term stability, and reduced maintenance needs. Tests conducted in the laboratory and at a full-scale model mine compare the performance of catalytic heat of combustion and infrared sensors operating under test conditions designed to simulate airflow conditions underground.

Jan 1, 2009

By Kermit Allen

Storing natural gas in solution mined salt cavities appears to be one of the more promising methods being considered by some major gas transmission companies for meeting peak demands. Historically, these companies have been faced with the problem of meeting peak demands when the source of natural gas is located hundreds of miles from the marketing area. Transcontinental Gas Pipe Line Corporation&apos;s position was further complicated because some of its offshore Gulf Coast gas supply wells may have to be shut in during hurricane alerts. Transco&apos;s solution was to construct. solution mined salt storage caverns adjacent to its pipeline near Eminence, Mississippi. (See Figure 1.) In 1965, Fenix & Scisson, Inc., was engaged by Transco to evaluate the feasibility of storing natural gas in caverns dissolved from salt at selected locations along Transco&apos;s pipeline to the East Coast. In June of that year a report was submitted to Transco concluding that this proposal was feasible and recommending several potential sites for storage development. Additional engineering and geological studies followed and in March 1968 the Eminence Salt Dome site was selected and storage construction began that year.

Jan 1, 1971

By A. L. Stomberg

Federal and State surface coal mining regulations require special handling of prime soil materials which result in additional costs, and no actual benefit when prime and non-prime soils are similar. The Coteau Properties Company proposes to mix both prime and non-prime topsoil and subsoils at the Freedom Mine in Mercer County, North Dakota, based on an analysis of soil physical and chemical characteristics which show these materials to be comparable.

Jan 1, 1985

By John F. Clarkson

White Pine Copper Company built and operated, from August, 1962 through May, 1963, a pilot plant to recover copper using a cyanide percolation leach of the sand fraction (+400 mesh) of the mill tailings (1, 2, 3). The pilot plant runs were metallurgically successful and preliminary engineering studies for a full scale operation were completed under contract by an outside engineering firm. Unfortunately, the net return projected at that time did not justify the proposed capital&apos; investment. In the summer of 1973 the project was revived. The rise in selling price of copper over the previous ten years, compared to the projected operating cost of the leach plant, increased the calculated net return on investment with the most recent figures showing a 30% DCF. Basically, the reason for this favorable shift in profitability was that the cost for many of the reagents did not go up as fast in the previous ten years as did the selling price of copper. Using the Chemical Marketing Reporter costs, NaCN sold for 18.3¢/lb in 1963 and 20.75¢/lb in August, 1973. During this same period H2S04 went from $23.50 per ton to $35.90 per ton. In comparison, producer&apos;s prices for electrolytic copper were 31¢/lb in 1963 and 619 in 1973. Thus the price of copper went up 97% while the two reagents only increased 13% and 53%, respectively. The capital investment also escalated but, again, not to the same extent as the selling price of copper. These price differences no longer are valid&apos; but they did provide justification for reexamining the project.

Jan 1, 1975

By Patrizia Pereyra, M. Guzman, C. Toledo, J. A. Rau, A. Ruiz

The use of mining tailings-based geopolymer binder as a substitute for cement can be an interesting alternative to the problem of final disposing of large volumes of them. Indeed, mining tailings have a high silica content, which makes them suitable for geopolymerization. The tailings samples contain Cu, Pb, Zn, As, Sb, Cd and Bi, mainly. X-ray diffraction results show that the tailings are composed of quartz, SiO2 (81%). Geopolymerized tailing samples (GTPS) were obtained by varying the ratio of SiO2/ Al2O3 and SiO2/NaOH. The compressive strength of the GTPS varied between 2 MPa and 8 MPa. The electrical conductivity in the leaching tests varies between 13.91– 16.11 mS/cm2 indicating that ions are present in the solution. However, the pH = 10.5 indicates that acidity is not being generated. The element that mostly leaches is iron. The highest percentage of leaching is observed for cadmium (69%) and chromium (93%). The concentrations of elements are under the maximum permissible limits for water according to the Peruvian legislation. However, mass transfer leach tests and immersion leach tests must be realized.

Feb 1, 2024

By Ramesh Kumar Chauhan, Umakant Sharma, Manwendra Pratap Singh, Ashok Kumar Chadha

The power sector in India has an installed capacity of 267.637 GW as on March 2015. Out of this total installed capacity, the hydropower sector contributes 41,267.43 MW as renewable energy source. The development of various proposed hydropower schemes in India are primarily concentrated in mountainous regions of Himalaya and often involves underground tunnelling. Underground tunnelling of considerable magnitude is generally associated with adverse geological conditions and associated geological surprises. The main objective in case of Tunnels constructed especially for hydro projects, which carry enormous quantum of water is that, it should not leak. Moreover, the tunnels which are part of water conductor system should resist the inflow of water from the surrounding ground in order to avoid draining of natural water sources and lowering of existing groundwater levels. Lowering of water table may result in subsidence and damage to existing surface structures, loss of capacity of drinking water schemes and in some cases even catastrophic sliding of landmass. Grouting and pre-grouting in tunnels serve three different purposes i.e., Stabilization, Strengthening and sealing of the rock mass around tunnels to avoid leakage of water from tunnels. In present paper, results of grouting methodology adopted during final construction stage of RHEP (412 MW) along with the introspection of Water Pressure Tests conducted for determination of the efficacy of grouting were elaborately presented. The process, of contact and consolidation grouting which is respectively followed by water pressure tests along entire reach of HRT (15.177 Km long) were also addressed in detail. Pertaining to the results of water percolation tests (before and after consolidation grouting), it was also attempted to categorize the behaviour of different rock mass classes/ conditions in reference to different quantum of grout intake and corresponding Lugeon values. Importance of planned and dedicated successful grouting procedure adopted in hydropower project at RHEP is also emphasized.

Jan 1, 2016

By F. J. Hurst

Phosphate rock, which is a prime source of phosphate used in fertilizer manufacture in the United States, contains uranium. In general, the uranium content of the rock increases with the phosphate content and most high-grade phosphate deposits (>30% P2O5) contain 0.01- 0.02% U3 8. The large tonnages of rock being mined represent a significant potential source of uranium that lends itself to recovery as a by-product of the wet-process phosphate industry. For example, in 1953, the U. S. Geological Survey estimated that recoverable phosphate reserves in the U. S. totaled about 5 billion tons and contained 600,000 tons of uranium. I This estimate did not include any rock from North Carolina which has since been estimated at about 2 billion tons. For the most part, the known, economically mineable U. S. reserves - estimated at about 7 billion tons - are concentrated in a few areas: 43% in the western states of Idaho, Montana, Utah and Wyoming; 28% in each of Florida and North Carolina and less than 1% in Tennessee. In the past, Florida has supplied about 80% of the total U. S. production, practically all of which is land pebble phosphate. All forecasts indicate increased production rates from North Carolina and the western states.

Jan 1, 1976