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By S. C. Sun

Pennsylvania has ample reserves of high-alumina clays which are potential sources of alumina, but many of these clays contain large amounts of iron, which makes them unsuitable for treatment by acid processes(1). The purpose of this investigation was to determine the optimum conditions for the selective hydrochloric acid leaching of iron (2-4) prior to the sulfuric acid extraction of alumina from Pennsylvania ferruginous high-alumina clays. This was accomplished by first testing the iron-bearing minerals and the clay minerals most often encountered in Pennsylvania clays to determine their rate of dissolution in hydrochloric acid solutions. The results of individual minerals were then based for leaching Pennsylvania clays with a 19% hydrochloric acid solution at the boiling point of the acid for approximately 30 minutes to achieve as high as 90% iron removal and only 2-5% alumina losses.

Jan 1, 1968

By G. J. Schneider

The higher stress zone adjacent to an underground opening causes a velocity anomaly that can be mapped in favorable conditions with an acoustic cross-borehole logging system. Bureau personnel used a specialized system at the Colorado School of Mines test site near Idaho Springs, Colorado, to locate the Edgar Mine tunnel and its associated stress anomaly. Data from the logging system' were processed with a tomographic image reconstruction algorithm to map the opening and the location of the high velocity zone around the opening. The velocity imagery from tomographic analysis compared favorably with predictions from numerical modelling of the location of the stress anomaly.

Jan 1, 1988

By C. Stoneback

The attapulgite industry saw a year of solid growth after a weaker 2003. Demand was up between 5 percent and 6 percent driven by almost all of the key markets. Construction continued to show record new housing demand, assisted by continued low interest rates. That drove strong growth in construction related markets like coatings, tape joint compounds and other construction materials applications. The agricultural markets rebounded modestly to increase sales for suspension fertilizers, animal feeds and pesticide carriers. Oil drilling also showed strong growth due to high oil and gas prices. Sales to molecular sieve applications grew due to petrochemical and construction demand. The export markets were assisted by further depreciation of the dollar. The only weak area was in nonagricultural granular sorbents, where other sorbent materials continued to dominate.

Jan 1, 2005

By John O. Marsden

Process selection is the systematic development of the optun.m metal extraction route for a particular feed matenal and has two main objectives: (1) to optimize project economics, principally a function of gold recovery, throughput rate and processing costs, and to develop a process that satisfies all of the proct requirements including, for example, political and environmental considerations.

Jan 1, 1992

By A. G. Journel

The indicator random function formalism allows a common coding of hard numerical data, constraint intervals, and soft qualitative information as prior probability distributions. The soft kriging algorithm allows interpolating these priors into posterior probability distributions of the unknown. The curse of ?negative kriged grades? is solved. The consideration of additional soft information, whenever deemed necessary, becomes possible within the framework of well-proven kriging techniques.

Jan 1, 1986

By V. R. Voller

The WTBAL computer program for evaluating material balances for minerals processing flowsheets was developed at the MRC and has been in general use for a number of years. This paper reports on two enhancements to the basic MTBAL routine. The original program accounted for errors in the process measurements and used estimates of measurement variability to calculate stream weights. Unfortunately, the estimate of measurement variability was fixed over all streams. In the enhanced version of MATBAL, named IMTBL, the program equations and their solution procedure have been modified to allow the estimated variability in a process measurement to vary from stream to stream. The .second enhancement involves making MTBAL interactive. As such, the user now prescribes his information in an easy-to-use fashion in a conversational mode via a terminal. Finally, an assessment of the feasibility of implementing IMTBL on microcomputer systems will also be reported.

Jan 1, 1982

By H. J. Sohn

Systematic studies were carried out on the adsorption of the silver thiourea complex on activated carbon. The experimental isotherm data fit the Freundlich isotherm equation. The adsorption rates increased with increasing temperature and decreased slightly with the increase of free thiourea concentration. The concentration of sulfuric acid had little effect on the adsorption rate. Adsorption kinetics correlated well with the Elovich equation, indicating adsorption is the rate-determining step.

Jan 1, 1987

By Ralph Bernstein

The processing of earth observation sensor data by digital technology is almost two decades old. Only recently, however, has this technology become practical and economical. The reasons for this are interesting to analyze, and they provide some insight into what the future may bring. Some of the earlier activities and their limitations, current systems and their applications, and future technology direction are summarized.

Jan 1, 1979

By S. S. Peng

A hybrid boundary element-finite element model was formulated to model roof bolt reinforcement of the roof strata with bedding planes. This model was used to analyze the stress distribution around a rectangular opening with variables such as opening width-height ratio, number of bolts installed, number/location of bedding planes, in-situ stresses, etc. The most critical areas are identified and the number and length of roof bolt required are then determined. Two case examples are illustrated.

Jan 1, 1989

By Peter J. Lawson, John A. Rideout, Gregory W. Dicinoski

A considerable body of literature directed towards optimising the efficiency of gold and silver extraction from cyanide leach liquors has appeared in recent years. A few examples from dissolution to solvent extraction to adsorption in carbon-in-pulp (CIP) and resin-in-pulp (RIP) operations follow. Selective leaching of gold from copper-gold ores using ammonia-cyanide mixtures extends the % copper which may be tolerated in ores (Ruane, 1991, LaBrooy et al., 1991, Costello, 1991). The removal of copper and recycling of cyanide from high copper ores is another important development (Sceresini and Staunton, 1991). Solvent extraction of alkaline cyanide liquors (Riveros, 1990, Mooiman & Miller, 1991) and solvent aided elution in CIP (Muir, et al., 1985) look promising. Recent definitive papers on the mechanism of adsorption of aurocyanide by activated carbon should lead to more efficient use of CIP (Adams and Fleming, 1989, Klauber, 1991). Strong and mixed weak-strong base resins have been applied in RIP for aurocyanide extraction in Russian Plants since the 1970's (see for example Borovskii et al., 1985, and references cited in Fleming, 1988a). Fundamental studies on applications of commercial weak and strong base resins-in-pulp (Fleming & Cromberge, 1984a, b, Fleming 1988a, Hosking 1984, Riveros and Cooper 1987) have generated much interest in RIP. Detailed comparisons of CIP vs RIP efficiencies at Mintek in South Africa (Fleming et al., 1988b), and the inefficiency of CIP in contact with clay led to the commissioning of the strong base RIP Golden Jubilee plant in 1988. Its operation and improvements have been reported (Seymore and Fleming, 1989, Fleming & Seymore, 1990). The use of anion exchange membranes for aurocyanide extraction shows some promise (Mauthoor et al., 1991). However, the development of new gold specific resins at Mintek (Green et al., 1984, 1986, 1990, Johns and Green, 1991) and elsewhere (Asker et al., 1987, Wilson et al., 1987, Harris et al., 1992) should improve the viability of RIP processes. The polydiallylamine gold specific resins (Hodgkin & Eibl, 1988, Fawell et al., 1992a, b) have high capacities for auro cyanide recovery from high concentration liquors. The use of guanidine based liquid and solid ion exchange extractants for gold was recently reported by the Henkel Corporation (Kordosky., et. al., 1993). Such specific resins tailor made for gold and/or silver cyanide extraction should lower overall cost by improving metallurgical efficiency. In the case of strong base resins this selectivity largely eliminates the problems of poor base metal elution and/or poisoning. The work reported here outlines the approach taken at the University of Central Queensland to synthesize sterically hindered strong base anion exchange resins which are designed to have high selectivity for auro- and argentocyanide complexes. It summarises selectivity tests on low grade cyanide leach liquors from several mines. It also examines an RIP vs CIP comparison, and investigates the elution properties and cycling of one such promising resin.

Jan 1, 1993

By Irwan Halim, Young Jin Park

A new tunnel lining was designed for rehabilitation of the existing unlined Weehawken Tunnel in New Jersey. Structural assessment using beam spring models was performed for the lining design as a drained structure at the invert with a waterproofing umbrella. Empirical Federal Highway Administration (FHWA) guideline was typically adopted for estimating hydrostatic pressure, which recommends full hydrostatic pressure at the crown and ten or twenty-five percent gradual reduction from the initial pressure toward the invert. Finite element seepage analyses were conducted for the actual conditions based on anticipated drainage behind the lining and impact on the structural design. Considerations will be provided on the existing guideline for estimating hydrostatic pressures.

Dec 1, 2022

By W. Z. Choi

A model describing size reduction and mineral liberation during grinding has been extended to include multiple classes of composite particles. The majority of the model parameters have been directly determined using computerized image processing equipment to analyze the products from batch grinding tests. A coarse-grained sphalerite ore from Tennessee, representing a nearly ideal binary mixture of sphalerite and dolomite, has been used to experimentally validate the model for the case of dry, batch grinding. In all cases, excellent agreement has been observed between the model predictions and the experimental results.

Jan 1, 1986

By Paul A. Roy

The North Shore Connector Project for the Port Authority of Allegheny County constructs twin Tunnel Boring Machine (TBM) tunnels through cohesive soils and rock beneath the Allegheny River and a narrow city street in Pittsburgh, PA. The tunnel alignment includes an historic building on shallow foundations, modern buildings on deep foundations, and an office building constructed directly over the alignment during the design of the tunnel sections. This paper provides an overview and update of the general site conditions, TBM tunnel design, and support of excavation for the TBM launching pit. Deformation limits, ground improvement, monitoring and mitigation plans are also discussed.

Jan 1, 2008

By L. A. Arrington-Webb

Forty-four states produced clay products during 1994 for a total value of $1.6 billion. This was a 3% increase in total tonnage and a 7% increase in value from 1993. Kaolin Domestic production of kaolin during 1994 was estimated to be 9.3 Mt (10.2 million st), according to the US Bureau of Mines (USBM). Georgia remained the leading producer with 7.5 Mt (8.2 million st), followed by South Carolina with 535 kt (589,000 st). Kaolin used as a paper coating or filler pigment accounted for 51% of domestic consumption. Other uses included grogs (14%), fiberglass (5%) and plastics (4%). A reclassification by an Alabama producer of fire clay to kaolin accounts for the introduction of kaolin used in grogs. This also accounts for the apparent decrease in the use of kaolin in paper from 60% in 1993. However, the actual amount of kaolin used in paper was the same.

Jan 1, 1995

In this paper, we present design and implementation details of a fuzzy-behavior-based controller for an automated excavator. This robotic excavator must be equipped with sensors, actuators and an embedded control system. The excavator controller uses neural-networks to interpret forces and torques gathered from bucket mounted force sensors during the excavation process. Implementation details and experimental results using the fuzzy behavior based excavation controller are given for several excavation tasks. These excavation tasks demonstrate some of the complex skills that are essential for an autonomous mining excavator controller.

Jan 1, 1996

By A. B. Szwilski

The mineability and coal processing costs are influenced largely by the structural and physical properties of the coal seam. The mining process involves coal cutting, pillar support, crushing, and floating. A correlation between the rank, ash content, and coal strength/stiffness is discussed. The coefficient of variability of rebound tests on the face of various coal seams are compared with those of laboratory compressive strength tests by other investigators.

Jan 1, 1988

By W. R. Dearman, N. Turk

The theoretical relations between the strain and stress Mohr circles make it possible to establish a relation between the internal friction angle [ ] and the Poisson's ratio (v) of rocks. The internal friction angle is related to the Poisson's ratio as Sin [-] = (1 - v)/(l + v). This relation gives lower friction angle values than the triaxial Mohr envelopes and higher values than those given by surface sliding friction tests.

Jan 1, 1986

By G. A. Rosario, G. Peach

Twin 8.5 m diameter, 10 km long headrace tunnels under overburdens of up to 1870 m were excavated for the neelum jhelum hydroelectric project in north-eastern pakistan using two main beam gripper tunnel boring machines (tbms). Rock bursts were encountered and presented a significant danger to personnel and equipment. Micro seismic monitoring was installed to analyze rock burst characteristics and to create a database for future reference. Correlation of rock burst characteristics improved the ability to predict the likelihood, location, severity, and number of rock burst events. This paper presents the analysis of the micro seismic data

Dec 1, 2022

By Charles Morris, Patricia Petty

Charles Morris Minerals engineers have a new opportunity to shape their industry's future. They can help secondary school teachers in their own communities improve their scientific knowledge and thus be better prepared to teach their students. Local sections of AIME and other groups are being asked to sponsor expense-aid scholarships for teachers who complete the summer field course A Total Concept of the Mining Industry. Now in its 18th year, the six-week summer course is presented by the Colorado Mining Association Education Foundation Inc., in cooperation with the Colorado School of Mines Office of Special Programs Continuing Education. The course will be held June 9 through July 18. "In the past, we have been successful in soliciting support for teacher-scholars from many organizations, corporations, and individuals within the industry," said John Robertson, Jr., Foundation chairman. "Now we hope to enlist the help of engineers at the grass roots level in identifying qualified local teachers and giving them what it takes to participate in this continuing education program." Robertson said the course provides secondary school teachers, counselors, and administrators with a working knowledge of the mining and metallurgical industries. It also helps teachers recognize career opportunities for their students. "With the industry facing a challenging new era, we must have teachers who can relate the excitement of this challenge to their students. They will inspire future generations of resource finders, developers, and managers," he said. More than 670 teachers in 27 states, including 45 graduates of the "class of '85" have completed the course and gained six semester hours of graduate credit. The Foundation's Planning and Curriculum Committee meets regularly to develop the course outline and recruit the faculty. Lecturers are selected on their ability to communicate with people not familiar with the industry. Last year, 67 faculty members came at their own time and expense to discuss their specialties, ranging from exploration to marketing. Normally, teachers receive scholarship aid in the form of tuition and fees, and transportation and meals while on field trips. Expense-aid scholarships cover room and board on campus for those beyond the Denver-Metro area, and travel to and from Golden. "We hope to broaden the appeal and the geographical range of the program," Robertson said. Inspiration for the field summer program for teachers came in 1967 from a mining engineer, the late C.L. (Lindy) Barker, a 1931 graduate of the Colorado School of Mines. Barker and a group of concerned individuals convinced the Colorado Mining Association to accept sponsorship of the course in 1968. The Colorado School of Mines and its Office of Special Programs and Continuing Education agreed to be a co-sponsor to give it accreditation and provide physical facilities and coordination. The first course was held in 1969. Operating funds were solicited from industry to pay tuition, course material, the cost of a course coordinator, field trips, and overhead. Through the years, personal contact by an industry representative has been the most effective teacher recruiting tool. Through expense-aid scholarships provided by local sections of professional organizations, such as AIME, as well as CSM alumni and other friends, there will now be a greater incentive for more teachers to get to know the minerals industry and pass that knowledge on in the classroom.

Jan 3, 1986

By Jan Jekielek

Increasing capacity of bulk material handling systems creates difficult problems for accurate in-line material weight measurements. At the same time increasing system complexity and growing user demands call for more measurements. Precision in-line weight measurements for bulk materials are usually accomplished by application of conveyor belt scales. Belt scale accuracies listed by scale vendors are applicable for ideal situations with suitable conveyor design, belt scale location and calibration means. This paper attempts to provide designers and users with simple means to evaluate belt scale accuracy for practical scale installations. Based on known mathematical models simplified formulas for measurement errors are derived and discussed. These formulas allow for simple determination of achievable accuracy for alternative scale installations on the conveyor, conveyor designs, etc.

Jan 1, 1979