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By George F. Klernrnick

The Pokorny sulfur deposit is located in the northwest comer of the Delaware basin in the Rustler Springs sulfur district of west Texas. To date, 57 sulfur test wells have been drilled by Addwest Minerals delineating a resource of greater than one million long tons (It) of native sulfur. The deposit, hosted by the Permian Ochoan Castile Formation evaporite sequence, is a sulfur-bearing bioepigenetic limestone replacement of banded bituminous anhydrite. Three distinct mineralized horizons are present that correlate with zones of halite dissolution in the Castile. Sulfur mineralization occurs as hydrocarbon-poor disseminated grains, and as crystalline linings of discontinuous planar voids and large vugs.

Jan 1, 1992

By Malcolm J. McPherson

This paper describes the algorithm used in a BASIC program for an IBMXT microcomputer, to simulate the underground mine climate. The program called CLIMSIM has been developed and refined over several years as a result of considerable use at operating mines. The program has been designed to be easy to use and be understood by the practicing mine ventilation engineer. It provides predictions of the work place climate, so that the optimum ventilation/cooling system can be designed to obtain a certain air cooling power or effective temperature at the work place. An example is given of the application of the program to a mechanized cut and fill stope at the Homestake gold mine in South Dakota.

Jan 1, 1986

By R. L. Sandefur

Any geostatistical study involves (implicit) hypotheses about 1. The distribution function 2. The drift of the data 3. The (underlying) variogram Once these are known, most other results follow from geostatistical theory. However, to date, there have been few theoretical studies on testing these implicit hypotheses. Most of the published studies in this area have dealt with the fluctuation of the variogram or the sampling distribution of the variogram (Journel and Huijbregts, 1978; Davis and Borgman, 1979). Questions regarding these hypotheses regarding a given deposit arise often. Coal geologists often infer channels and washouts on the basis of thicknesses data. Zoning is recognized in a variety of metal deposits. A test as to whether these inferences are valid on just chance occurrences would have widespread application. .It is standard geostatistical practice to "eyeball" fit variograms. In the early exploration phase when just a few pairs are available, the variogram often displays wide fluctuations and there may be considerable doubt about which variogram model to use.

Jan 1, 1982

By Rocky Gunderson

When operations begin early next year at the $100-million Port Kembla coal loading facility in New South Wales, Australia, a sophisticated computer system, directed by two of Hewlett-Packard's HP1000 mini-computers, will perform a number of functions ranging from monitoring and reporting arrivals and departures to maintaining a library of events for up to one year. The three-processor HP1000 system configuration, valued at $215,000, is one of the largest single orders, in terms of dollar value, ever submitted in Australia for Hewlett-Packard's line of engineering and manufacturing minicomputers. The processors will be linked in a fully "backed-up'' configuration using Hewlett-Packard's fourth generation distributed networking system, DS/1000-IV, making the system one of the most sophisticated in Australia. Interfaced to a number of weightometers and programmable logic controllers (PLCs), the computers will be the heart of a coal inventory system for the facility which, in its first phase, will be capable of handling more than 13.5 Mt/a of coal. The computers will report on all plant functions, including conveyor belt and water spray operations. Specifically, the system will: • Monitor and report all coal movements related to road and rail deliveries, dispatches from ship loaders, and interstockpile transfers. •Maintain a ''running log" of all events pertaining to overall plant operations, such as conveyor starts and stops and anti-pollution spray activation. • Accept and maintain plant data entered manually or acquired automatically from various remote locations via either visual display units (VDUs) or PLCs. • Maintain complete historical records of all transactions and related plant events for up to one year. • Provide a facility for stockpile management, modeling-type programs, and training or other simulation activity. The facility was designed with the following characteristics in mind, based on an analysis of requirements for an automated coal loading operation that would optimize productivity and be flexible to change and grow with facility needs and changing technology: • Continuous Operations-Due to the need for continuous plant logging and control, the overall facility will be capable of uninterrupted, 24¬hour operation. • Handling Current and Projected Workloads-The facility will be capable of not only handling current workloads, but also any additional workloads required during future coal loading operations. • Expansion-The facility will be capable of expansion, for a minimum cost, at any time with minimum disruption in operations. • Single Source of Supply and Maintenance-The facility will be supplied and maintained by one supplier, through hardware and software maintenance support contracts. System Configuration Two HP1000 minicomputers, each with 500K bytes of main memory, will be front-ended by a pre-processor with 256K bytes of main memory. These three systems, active, backup, and front-end, will be interconnected into a triangular array, as shown in the accompanying diagram. Under normal conditions, the front-end will transmit plant status data to one of the main systems, whose primary function will be to monitor coal flow and maintain a relevant dialogue with operators. The front-end, therefore, handles all communication with the plant PLCs, effectively removing this overhead from the current plant monitor (either of the two main systems). The front-end pre-processes and post-processes all information flowing from the plant monitor to the PLCs and vice versa, thus effectively handling all communication between the two units. A second main system will handle reporting, administrative, and modeling functions, and will also be capable of performing both front-end and monitoring operations. Linking all

Jan 11, 1981

By K. N. Han, P. B. Queneau, A. Stojsic, M. J. Collins, V. J. Ketcham, R. M. G. S. Berezowsky, W. D. Vardill

The bulk of the ore found in the Lihir Island deposit is refractory in nature, with the gold contained in auriferous pyrite. In support of an evaluation of the development of this deposit by Kennecott (a wholly owned subsidiary of RTZ) and Niugini Mining Ltd., testwork has been carried out at the Sherritt Research Centre to demonstrate the amenability of the Lihir ore to pressure oxidation pretreatment to liberate the refractory gold. The results of pilot plant treatment of the Lihir ore in a continuous circuit with a feed rate of between 10 and 30 kg/h ore are described. The integrated circuit comprised pressure oxidation, residue washing, and gold recovery from the washed residue by carbon in leach or carbon in pulp cyanide leaching. Significant factors affecting gold recovery included temperature and retention time in the pressure oxidation step, and the concentration of soluble chloride in the feed. Gold extraction from well washed ore, after oxidation at 210°C for 66 minutes in the autoclave, was typically between 94 and 96%, compared with less than 30% by direct cyanidation.

Jan 1, 1993

By James J. Kabat, James A. McDonald

Impregilo/SA Healy JV recently completed this Project using the first slurry shield TBM’s in the United States. The Project used two TBM’s to mine 18,000 feet in sands, gravels, and silty alluvial materials under the Willamette River and downtown Portland, Oregon. This paper discusses alignment and geological conditions, equipment selection and plant setup, and tunnel excavation means and methods, parameters, and results. Extensive hyperbaric operations were required and will also be discussed.

Jan 1, 2007

By D. L. Murr, J. R. Jensen

Testing was conducted on a Minnesota Iron Ore concentrate with Cook Clay as a binder using compressive sheer mixing to enhance the performance of the agglomeration mechanism. The testing was conducted on a bench scale at the Midland Research Center the summer of 2004. Results of the test program will be presented that shows the impact of compressive sheer mixing had on the strength achieve in a green ball.

Jan 1, 2006

By Georgene Renner, William R. Yernberg, William Gleason

American Commercial (ACI) offers a selection of ground control solutions. Beginning with steel liner plates installed in the Gratiot Avenue sewer system in Detroit, MI 1920, ACI is one of the leading designers and manufacturers of underground steel supports in North America. ACI is also a leader in fire-proofing underground structures with its Promat Fire Protection Boards. The sandwich panels have been used in many new and retrofit tunnel and underground construction projects worldwide. Ease of installation and replacement, cost effectiveness and superior performance have made this product line the premier choice of owners and designers for structural protection, fire-life safety requirements and architectural finish needs.

Jan 1, 2007

By K. N. Han, M. C. Fuerstenau

Challenges in five major areas of hydrometallurgy are presented and discussed. These are: leaching low-grade oxide and sulfide ores; oxidative leaching of sulfide concentrates; processing refractory ores; bacterial leaching and processing: and secondary metal recovery.

Jan 1, 1989

By Leigh Freeman

This article provides an overview for a series of leadership development workshops offered through the SME Young Leaders Program. The first of these workshops, “Accelerated Development Plan,” will be held at the upcoming SME Annual Meeting in St. Louis, MO on Sunday, March 26. How does a foundation of technical competencies relate to the development of social competencies necessary for management and leadership roles in the resource sectors? Technical competencies provide the foundation for a successful career. Social competencies provide the framework on that foundation. Successful leaders will be those who develop competencies in all areas.

Jan 1, 2006

By D. M. Abbott, H. J. Sandri

The geoscience matrix method has proven useful for valuing metallic mineral properties lacking delineated mineral resources or reserves. However, the method explicitly excludes commodity markets from the factors considered; marketability is assumed. When valuing industrial mineral properties, marketability cannot be assumed, it must considered. Market considerations may also significantly affect the standard weightings of geoscience matrix parameters such as the proximity to known deposits. In some cases, such proximity is desirable but in many cases it is undesirable. Application of the geoscience matrix method to industrial mineral properties therefore requires thoughtful, market-related adjustments to the basic geoscience matrix methodology.

Jan 1, 2000

By Colin C. Harris, Jie Zheng, P. Sornasundaran

Powder surface and polymer structural changes during stirred milling have been studied as a function of grinding time, solid concentration and polymer molecular weight. It was found that specific surface area of limestone particles can be increased over 100% by using polymer additives. Particle surface and polymer structure were also found to change during grinding. Powder surface and polymer properties have been determined using Surface Tension, Fluorescence, TOC and HPLC/GPC analysis, and surface and polymer properties are correlated with operating variables and the mechanisms involved are explored. Particularly, the fragmentation of the polymer molecules was found to occur during long term grinding and this was beneficial for ultrafine grinding.

Jan 1, 1998

By V. I. Lakshmanan, P. D. Tackaberry

The use of activated carbon as an alternative to Merrill Crowe precipitation to recover gold from pregnant leach solutions is recognized. Recovery using activated carbon, however, suffers from the interference, due to organic fouling, clay content and increasingly from the presence of elements such as copper. Ion exchange separation technology is familiar to the mining industry (uranium) and its potential application to the gold mining industry is evaluated with considerable efforts by research workers in South Africa, Australia, and North America. The present paper reviews in detail the status of the research work that identifies potential opportunities.

Jan 1, 1990

By Gerald H. Luttrell, Jaisen N. Kohmuench, Michael J. Mankosa

A new separator, known as the Hydrofloat cell, has been developed to overcome limitations of traditional flotation cells in recovering coarse particles. In this process, small air bubbles are introduced into a hindered "teeter" bed of fluidized solids to create light bubble-particle aggregates that can be separated based on differences in density. Laboratory tests conducted with coarse phosphate feeds indicate that the Hydrofloat cell is capable of increasing BPL recoveries by nearly 20% over conventional flotation methods. Based on these encouraging results, a pilot-scale Hydrofloat cell was fabricated and installed at a central Florida phosphate plant. Test data collected using the pilot-scale unit suggest that the BPL recovery of the plus 35 mesh plant feed can be increased by more than 40% through the application of this new technology. This improvement is particularly beneficial due to the very high grade (-73% BPL) of the plus 16 mesh particles in the Hydrofloat concentrate. This article describes the theoretical basis for the development of the Hydrofloat cell and provides an overview of recent laboratory and pilot-scale test results.

Jan 1, 1999

By James S. Hanson

Existing models proposed for the bacterial leaching of metal sulfides generally fail to predict solubilization rates at times greater than a few tens of hours. The reasons for this may be that these models are empirically based and use first order bacterial and chemical oxidation rates. This type of model is satisfactory for short time predictions (on the order of 20 hours) when the bacterially catalyzed dissolution is relatively minor. However, when bacterial action becomes more pronounced, these models consistently predict higher dissolution rates than those commonly observed in laboratory experiments. The present model uses several fundamental chemically and biologically based assumptions to predict the dissolution rate of a chalcopyrite concentrate for extended leach times up to the precipitation of jarosite. The main assumptions made are that Monod growth kinetics prevail, T. ferrooxidans adsorb onto the surface of the mineral (not necessarily mineral specific), and that during periods of high growth oxygen transport may become rate limiting. The model also relies on the energy efficiency of the bacteria in fixing carbon (growth yield) and correlates this value with available surface area of the mineral particles and the bacterial growth rate.

Jan 1, 1989

By G. D. Hood, B. E. Davis

A fundamental study of the mechanisms involved in the conditioning of coarse Florida phosphate has led to some interesting discoveries. Studies by the US Bureau of Mines have shown that conditioning time and mixing intensity greatly affect the grades and recoveries of the phosphate minerals and quartz in the rougher concentrate. In particular, as the conditioning time or mixing intensity increased, the phosphate recovery remained constant while the amount of quartz floated decreased. This phenomenon is contrary to conventional wisdom and could lead to a more efficient coarse flotation circuit.

Jan 1, 1995

By Terence G. McCusker

Precast concrete segmental tunnel linings have been used since at least 1903. More serious attention was devoted to them in England during the World War II steel shortage and they have become increasingly common since that time. They are now coming into common use in the United States, especially as primary linings for soft ground tunnels and for rock tunnels in poor ground, although they have also been used as final lining, especially in rock tunnels. The developmental logic, design considerations, and current practices are examined. Particular attention is given to unbolted linings, with and without secondary linings. Probable future developments are considered.

Jan 1, 1989

By ev, Ze&apos Reches

The growth of networks of shear fractures is explored in a series of experiments with samples of wet clay. The samples are subjected to plane strain deformation in a rigid apparatus. The individual fractures observed on the upper surface of the clay samples grow longer by three mechanisms: in-plane propagation, off-plane propagation and coalescence. New, active fractures cut and displace older, less active ones. The lengths of individual fractures display lognormal distribution in most cases and power distribution in fewer. The calculated length parameters in the experiments, as well as in three field cases discussed here, suggest that the fundamental parameters in fracture analysis are the normalized cumulative length and the length of the shortest fracture measured.

Jan 1, 1986

By S. M. Hsiung, Wen H. Su, Syd S. Peng

This paper examines the interaction problems of multiple seam mining by combining underground investigation, laboratory testings, and numerical modeling. One case of multiple seam interaction that occurred recently in West Virginia was carefully studied. Causes for the interaction problems were identified and the corresponding mining recommendations were proposed. The principle of pillar columnization and the effect of a remnant pillar on mining operations in the underlying and over- lying seams were also carefully examined. Considerable attention was given to the effect the pillar size, the pillar width, the coal stiffness, the extraction ratio, the degree of inhomogeneity in the interburden, the overburden thickness, the mechanical properties of the interburden rocks, the strata inclination, the interburden thickness, and the in-situ horizontal stresses have on the pillar load transfer mechanism.

Jan 1, 1986

By Sumit Kumar Hota, Asadi Srinivasa Reddy, Ashok Kumar, Ashish Agrawal, Surajit Sinha, Chandra Sekhar, Tanay Ray

In the current operational facility, due to the absence of pellet pot facility, a novel technique is developed wherein the pellets with different chemistries prepared in the laboratory are fired in an induration machine by placing them inside the Inconel baskets. In the present work, an attempt is made to optimize the pellet chemistry by developing 2 different flux pellets, viz., low basicity (B2: CaO/ SiO2 = 0.3) pellets and high basicity (B2 = 0.9) pellets, and further the effects of basicity on pellet properties, viz., cold compressive strength, porosity, swelling index, reducibility index, and softening and melting temperature, are studied. It has been found through the multiple operational trials that increasing the basicity of pellets from 0.3 to 0.9 results into improving the pellet strength, reducibility and softening and melting characteristics. Moreover, it is observed that the swelling index of pellets is reduced by adding 2% MgO to both low and high basicity pellets that could be attributed to the formation of high melting point slag in pellets. The operational trial has resulted into producing pellets that exhibit a combination of desired mechanical strength, improved swelling, and reducibility index and possess better softening–melting behavior among all the chemistries studied.

May 24, 2022