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By A. J. Rergis

During the past ten years a number of papers have appeared describing zeolite occurrences in the western United States in Mesozoic sedimentary rocks, altered bedded Tertiary pyroclastics, playa lakes, hot springs, and amygdaloidal basalts. With the emergence of natural zeolites as economic industrial minerals it appears, useful to develop a system of classification to delineate those zeolite deposits of economic interest which were not discovered until the middle 1950's. The first attempt at a classification of naturally occurring zeolites was made in 1914 by Lindgren l when he classified the zeolites into eleven groups based on their mode of occurrence. The zoned zeolites in the Mesozoic rocks of New Zealand and elsewhere were classified according to the mineral assemblages by Fyfe, et al.2 in 1958 as a zeolite facies corresponding to low grade regional metamorphism. In 1966, Hay suggested as an alternative to the preceding classification one which would "classify as diagenetic all mineral assemblages produced in sedimentary rocks under conditions in which zeolites are formed." In this paper a classification is proposed with the objective of providing an overall perspective of the zeolite occurrences in the western United States.

Jan 1, 1967

By Graham A. Mathieson

The precise definition of an ultimate or economic pit has, over the years, received much attention in the literature on the subject of mine planning. Unfortunately, relatively little has been published in the area of pit sequencing and scheduling--an aspect which is typically of much greater economic significance both during the life of a mining operation, as well as in the evaluation of an exploration project. This paper discusses an overall mine planning methodology with emphasis on the design of an optimal sequence of pit expansions or phases. Although the concepts given are not new, it is hoped that some practical suggestions will be made. The paper will also describe graphical techniques which have been found useful in comparing the merits and impacts of alternate planning strategies and production schedules.

Jan 1, 1982

By R. O. Vernon

The Florida Peninsula has existed as a part of a much broader plateau, since at least the Early Cretaceous. This plateau, the Floridan Plateau, now consists of the present peninsula and a broad submerged shelf of equivalent size extending the length of the state and out into the Gulf of Mexico. Florida Peninsula was separated from the mainland United States by a negative area called the Suwannee Straits. To the south of this feature existed an environment similar to today?s Bahamo Banks where very pure calcium and magnesium carbonates with associated evaporites were deposited. Thus the Eocene and Oligocene contain little or no quartz sand or clay minerals except in the Panhandle west of the Suwannee Straits where some clastics were contributed by rivers from the north.

Jan 1, 1966

By William G. Doepken

The extensive use of rubber-tired support vehicles as a complement to a fleet of load-haul-dump and drill jumbo units has proved invaluable in maintaining scheduled multilevel/multiheading development drifting advances at the Henderson Mine. Support equipment, whether self-powered or towed, releases primary drill-blast-muck equipment from the supportive functions of ground control, utilities installation, steel and concrete construction and supply handling, thus providing both balance and increased flexibility to an underground, rubber-tired mining system. Experience has indicated that increases in man productivity and improved safety and working conditions coupled with decreases in overall costs and mining cycle times are realized with the inclusion of support vehicles in the mining fleet.

Jan 1, 1976

By J. R. Parga

Bacís mining is a young enterprise in Mexico that produces a pyrite concentrate rich in gold and silver. When gold and silver are associated to sulfide minerals, pre-treament such as: roasting, pressure oxidation and bioleching, is required to decompose the sulphides and thereby expose the gold and silver particles to the cyanide solution. A novel method demonstrates that the oxidation and dissolution of gold and silver in alka-line cyanide solution can be conducted simultaneously in the same autoclave in less than 90 minutes with a recovery that exceeds 96%. Factors affecting recovery efficiency such as pH, leaching time in the reactor, temperature, particle diameter, pressure, % of NaCN and pulp density were investigated.

Jan 1, 2007

By Andre Balt, Pierre Hofmeyr

It is only recently that automation has been applied to mining analytical laboratories. This paper describes the use of automation in the laboratory analytical process of hard-rock mining and geological samples and slurries in mining concentrator plant process control laboratories. Types of analysis include fire assay, XRF, ICP and wet chemistry. The benefits of automation are reduced unit cost of analyses, greatly reduced staff requirements, higher quality of data and very fast turn-around times.

Jan 1, 2005

By Wen Lan Chen

In the plant where the 800m diameter cyclone was tested, 500 STPH of 50m x 0 raw coal was pulped in a heavy medium tank and pumped originally to four 700mm heavy medium cyclones. For the test one of these units was replaced by an 800mm diameter cyclone with the subsequent feed pressure for both units sets at approximately 15.0 psi. Since this was a feed to zero plant, an appropriate bleed of heavy medium to the dilute medium circuit was established to en- sure that the cleaning of the 500m x 0.5mm raw coal would not be adversely affected by high levels of 0.5mm x 0 fine coal present in the heavy medium. The medium gravity measured varied between 1.41 and 1.43. During a three-hour test on June 10, 1983, the raw coal sample was collected from the feed belt while the clean coal and refuse samples were collected separately at proper locations along the product streams of the two different diameter cyclones. All of these samples were shipped to the laboratory for screen and sink- float analyses. The raw coal screen and ash analyses are shown in Table 1.

Jan 1, 1984

By Christophe Bragard, Brett Robinson

This paper reflects the challenges encountered during the construction of the light rail tunnels under Boyle Heights, in Los Angeles, California. Equipped with two state-of-the-art EPB TBMs, the construction team undertook the mining of twin bored tunnels in the Los Angeles alluvium. The gassy underground conditions dictated many aspects of the design of the tunnels, as well as the tools and means used for their construction. This paper will detail the challenges encountered during construction, as well as the means, methods and logistics used on the project. Discussion includes: EPB TBM machines with some very unique/specific features; complex assembly sequence due to limited shaft access; final precast concrete liner with double gaskets; NATM cross passage excavation in soft ground and below the water table; compensation grouting; mucking shaft arrangement.

Jan 1, 2007

By Ross Goodman, Jean-Luc des Rivières

The Ohio River Tunnel Project encountered multiple unexpected geotechnical challenges which, continuing to develop over time, hampered excavation completion and impacted the cast-in-place final lining technique and work execution sequence for the entire project. The continued degradation of the excavated hard rock tunnel conditions led to a unique, dynamic, geologic setting that forced the project to innovate new and adaptable measures allowing for a conventional cast-in-place liner to be completed in a safe and timely manner and minimize delay.

Jun 13, 2023

By L. Shwydiuk, A. Chrzanowski, W. Newcomen, G. Bastin, R. Wilkins

Automated monitoring of steep embankments allows the early detection of instability and can be used to avoid or mitigate possible slope failures. A system that uses multiple and different types of sensors has been created and successfully tested at the Highland Valley Copper mine in British Columbia. The system uses robotic total stations (RTSs) as the primary measurement sensor, with surveys repeated at predefined intervals selected to optimize operational efficiency. A methodology has been developed to improve the system’s accuracy and reliability by reducing the effects of systematic errors created by atmospheric refraction and unstable instrument and reference point positions. The inclusion of GPS sensors to monitor the RTS positions creates additional operational flexibility and maintains system integrity when insufficient reference stations are available.

Jan 1, 2003

By B. K. Mishra, R. K. Rajamani, A. D. Joshi

The liners are the most important part in the SAG mill operation. Hence, the liners and their design parameters are primarily studied to see its effect on SAG mill operations. Effective liner designs are directed to reduce downtimes, which is needed for the replacement of worn liners. There exists constant chance of improvement in the capacity of mill by studying the effect of liner design on the charge motion inside the mill. This need is satisfied by three-dimensional discrete element code "Millsoft", which uses Discrete Element Method (DEM) to analyze the motion of charge. This simulation of SAG mill keeps track of all the moving bodies like ball and rock and observes its interaction with liners and lifters. The recent work done on this software helps generating mill to more reality by putting conical wall at feed and discharge end, over the earlier flat walls. Millsoft is an effective tool to watch the change in the motion of the charge due to different types of lifter bars and different design parameters. It was concluded that by simply increasing chord length between the lifters and increasing the face angle of the lifters, capacity of the mill could be increased. On the other hand, this software can also be used to get power draft at the respective mill design.

Jan 1, 2002

Mine design and selection of ore processing capacity depend upon a correct estimate of the grade-tonnage distribution. The estimate must reflect what can be recovered and processed. The McCoy/Cove operation in central Nevada, USA, is a gold and silver mine. Case studies of recoverable reserve estimation for gold and silver were made using multiple indicator kriging and the log-affine variance correction. From this model, the grade-tonnage distribution was constructed. Optimal pits were generated by utilizing the distribution, and the results were compared with the pit generated by ordinary kriging. Studies indicate that the proposed method for multi-metal recoverable reserve estimation is more accurate than ordinary kriging in terms of both tons and the grade. Using recoverable reserves for mine design will maximize global recovery of mineral resources.

Jan 1, 1997

By R. A. Deju

The Basalt Waste Isolation Project of the U.S. Department of Energy is a part of the National Was re Terminal Storage Program. Its mission is to assess the feasibility of siting a nuclear waste repository in the basalt formations which underlie the Hanford Site of the U.S. Department of Energy. The progress in all program areas is summarized in this paper. Activities conducted to date have led to the identification of possible repository candidate sites within the Hanford Site.

Jan 1, 1981

By R. E. Johnson, L. V. Araújo, B. R. Palmer, L. M. Abrantes, G. W. Warren

The behaviour of chalcopyrite - mineral specimens and a Portuguese concentrate - in 2M chloride solutions prepared from hydrochloric acid and sodium chloride, has been characterized by cyclic voltammetry. The study has shown the influence of the potential and of the presence of impurities in the reaction schemes and their relative extent. The dissolution of chalcopyrite concentrate under potentiostatic control has been investigated and found to confirm the effect of the selected potential on the surface modification/rate of dissolution. An attempt has been made to correlate the information obtained with the response of the concentrate electrode to constant current treatments.

Jan 1, 1993

By Georgene Renner, William R. Yernberg, Steve Kral

Allmand exhibited its LSC 100Light Sequence Commander, the mining industry’s first automatic lighting and command control system. The system is available with all of Allmand’s portable light towers. The LSC100 uses a preset photocell sensor that allows the light tower to be automatically turned on or off. At dusk, the sensor engages the power unit and then activates the light. At dawn, the sensor automatically shuts off the light. The unit also features an eight-event digital timer that allows eight separate sequences daily. The LSC100’s sequenced light control ensures that the engine is started before the lights are turned on or off. This prevents possible generator damage that can occur if the unit is powered down under load. Also, a low-fuel shutdown sequence helps protect the generator from damage by automatically shutting down the unit when the fuel level reaches 10 percent. And the LSC100’s smart circuitry senses engine water temperature during startup, determines the glow-plug time requirement and schedules repeat intervals, if necessary, to start the diesel engine.

Jan 1, 2004

By Jean-Luc Cornet

Advances in conveyor technology over the past decade have enabled the design and erection of very long overland belt conveyors. Such conveyors usually require head and tail drives to lower the belt tension and belt strength required. This paper provides an overview of the problems encountered in controlling the head and tail drives on such conveyors and some of the solutions developed by CDI for several such projects.

Jan 1, 2002

Surface subsidence that results from longwall mining can be large magnitude and can affect significant areas. Conventional methods for subsidence monitoring include leveling, global positioning system (GPS), and photogrammetric surveys. Remote sensing techniques, including aerial LiDAR, terrestrial laser scanning, and satellite-based differential interferometric synthetic aperture radar (DInSAR), are also used to measure deformation associated with subsidence. DInSAR data are different than data from conventional subsidence surveys. Images capture data over large areas (hundreds of kilometers), and each pixel (data point) in an image quantifies the average displacement over an area of square meters. DInSAR data can have fairly high time resolution; imaging periods typically range from weeks to months.

Jan 7, 2020

By Terry P. McNulty

During the last 30 years, at least ten authors have dealt with startup ("ramp-up') times for minerals beneficiation, hydrometallurgical, and/or pyrometallurgical plants. Most have attempted to identity the reasons for delays and some have suggested attributes common to successful startups, as well as those shared by unsuccessful ones. The most recent has advanced a project characterization matrix as a predictive tool for qualified users. This paper will summarize past work, will review cause and effect, will outline an approach for refining our ability to avoid costly delays, and will seek guidance from professionals most likely to use such a tool. INTRODUCTION During the last few decades, many billions of dollars have been lost by investors in mineral industry projects that did not perform as well as their developers had hoped. The most common form of failure has been the inability to generate a profit quickly, and delayed achievement of planned production rate has been the chief cause. Minerals processing projects are by no means the only kind of plant to suffer from startup delays, as some authors cited in this paper considered inorganic chemical plants and other types of facilities. Furthermore, mines are not without fault and there have been many that were closed after years of disappointing performance. However, our interests as a group are most sharply focused on mineral processing and our database for such projects is relatively extensive. It is sufficient to say that the conclusions made or repeated in the following text can be readily extended to most types of projects.

Jan 1, 2004

By Steve Kral

Commodity price down cycles are a fact of life in the mining industry. And companies pre-pare for them as best they can. Evenso, operations are still curtailed or closed during those cycles, profits shrink, layoffs are inevitable and many companies do not survive. However, one of the few good things that occurs during down cycles is the new, innovative exploration, mining and processing technologies that come about during hard times. To survive the lean times, the mining industry turns to improved technology to decrease costs and hold the bottom line. And, because mining is a cyclical business, each down cycle brings about technology improvements that carry over into the good times.

Jan 1, 2004

By Gilbert C. Robinson

Manufacturers of brick and tile are showing growing interest in the possibility of manufacture of a clay bonded block. The block would have the shape of concrete block, but would be made without the use of Portland cement, Instead, the block would be made' from mixtures' of an aggregate and the present raw materials of the brick industry. The finished units would weigh 20 to 30 pounds and meet the specifications for Grade A concrete block. The present status of the clay block development shows one manufacturer actually in production of these units$, two additional manufacturers are attempting production and many manufacturers are actively engaged in development work. At least four major research laboratories are engaged in the development program. There are several different processes available for clay block production. These processes differ primarily in the type of aggregate used or in the type of forming operation selected. I would like summarize these possible methods.

Jan 1, 1960