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By K. C. Tran

This paper reviews the advancement of measurement technologies for the control of raw materials processes in the basic industries. The combination of digital technology and on line spectroscopy enables the development of intelligent instruments for composition and particle size analyses in real- time high- frequency control conditions. In many industries, the applications result in productivity improvement and energy savings. Plant specific examples include operating experience and benefits realized in sorting, blending and beneficiation processes. Instruments of the future not only measure specific parameters of the process and monitor its own health combined with self-corrective mechanics but also acts with intelligence to effect the quality of the process or regulate the primary apparatus.

Jan 1, 2001

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Amilton Barbosa Botelho Junior

A new step in the Bayer process has been used to recover NaOH and to reduce its content in red mud. After digestion, the residue is separated from the Bayer liquor and goes through press filters, which enables the recovery of NaOH and decreases the moisture content. It is well known that red mud is one of the most important sources of scandium. For this reason, the goal of this work was to characterize a Brazilian red mud (BRM) for scandium recovery. The sample was collected after the press filter system process. Analysis of energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and X-ray diffraction (XRD) was performed. Microwave digestion using an acid mixture was carried out to determine the concentration of the main elements. Fe2O3 represented 40% of the BRM, and the Sc concentration was 43 mg/kg. The SiO2 content was 24%, which is the highest value found in the literature, whereas the sodium concentration was the lowest. A literature review was carried out to compare results with BRM, as well as the current studies for recovery of scandium by the leaching/ion-exchange process. Scandium recovery using a leaching/ion exchange process may be possible with efficiency higher than 90%. The greatest challenge is the occurrence of silica gel formation during leaching.

Oct 19, 2020

By Robert J. F. Goodfellow, William A. T. Meakin, Kevin Clarke, Eric Cole

INTRODUCTION New York City Water Supply—Background and History Since the 1840s New York City has been developing the largest, and perhaps, the best urban water supply and distribution system in the world in terms of quality and reliability. One of the engineering marvels of the modern world, the New York City water supply and distribution system serves a population of almost nine million, including residents in nearby Westchester, Putnam, Ulster, and Orange Counties of New York State. The average daily supplies presently are running at almost 60 m3/sec(about 1,350 million gallons per day). The watershed for the New York City water supply system, under the jurisdiction of the New York City Department of Environmental Protection (NYCDEP), consists of19 reservoirs and three controlled lakes, and covers an area of approximately5,000 square kilometers (about 2,000 square miles) north of New York City. The watershed total available storage capacity is about two billion cubic meters (560 billion gallons) and is divided into three reservoir systems: the Catskill and Delaware watersheds located West of the Hudson River; and the Croton watershed, located east of the Hudson River, see Figure 1. The first element of the system, the Croton Aqueduct, started operations in 1842.Through several updates and expansions, the present-day Croton system was in place by 1911, providing a potential maximum supply of about 15 m3/s (about 340 mgd). The system includes ten reservoirs and three controlled lakes. In the late 1800s, with the tremendous growth of the City, New York City water engineers began to look for additional sources. Between 1907 and 1929, the City acquired water rights and constructed a new 148 km (92 miles) Catskill aqueduct to convey water from the Ashokan Reservoir to the City. The Catskill system also included the construction of the Kensico and Hillview Reservoirs just north of the City,

Jan 1, 2005

Steady increases in longwall production have required operators to apply greater quantities of ventilating air in an effort to control and dilute respirable dust. Significant increases in shearer speeds necessitate that longwall supports also be advanced at a faster rate. Both of these factors may contribute to overall respirable dust levels on the longwall face because as supports are lowered and advanced, broken material falling from the top of the canopy is entrained directly into the air stream. To address this issue, the Pittsburgh Research Laboratory collected respirable dust samples from four longwall faces to characterize shield-generated dust. This paper investigates the influence of air velocity and shield advance rates on respirable dust levels. Also discussed are engineering controls currently used to reduce shield dust and alternative controls being investigated by the National Institute for Occupational Safety and Health (NIOSH).

Jan 4, 2010

By J. C. Willett, J. R. Sanfilipo, P. D. Warwick

The U.S. Geological Survey has conducted an assessment of the Nation’s coal deposits that potentially could be mined during the next 30 or more years. For the Gulf Coastal Plain region, the assessment includes reviews of the stratigraphy, coal quality and resources, and coalbed methane potential of the Cretaceous, Paleocene, and Eocene coal deposits in the region. The results of these efforts are a series of digital maps, text, and tables published in CD-ROM format. Although abundant coal resources are available in the Gulf Coast region, coal quality issues may limit large-scale development in the future. Additional data are required to better evaluate the coalbed methane resource potential for the Gulf Coast region.

Jan 1, 2001

By K. E. Kolm, W. H. Langer

Developing natural aggregate resources (sand, gravel, and stone) creates environmental impacts. A systems analysis method has been designed to characterize the components of the environmental system, identify potential impacts to those systems, and evaluate the extent of those impacts. The step-wise method consists of problem definition, data collection, preliminary conceptualization and characterization, additional data collection, data analysis, and refinement. The method requires analyzes of various systems making up the environment, including land surface, geomorphic, subsurface, and groundwater systems. After system characterization is complete, the method focuses on identifying and evaluating potential environmental impacts to determine acceptable mining strategies.

Jan 1, 2001

By M. Fan

Dry coal separation technology has particular advantages in the applications in arid and cold regions, or low rank coal separation. The hazardous pollutants in low rank coals can not be efficiently removed by conventional wet coal separation processes because a considerable amount of porose and easily friable low rank coals suffer serious particle size degradation problems in water. In this paper, a novel dry coal separation method with a vibrated air-fluidized bed of magnetic fly ash and magnetite is put forward for dry coal beneficiation. The magnetic fly ash used in this study was derived from fly ash obtained as a byproduct of coal combustion. The vibration?s effect on the uniformity and stability of a magnetic fly ash air-fluidized bed was studied. The 6×0.5 mm dry coal separation results with a vibrated air-fluidized bed of magnetic fly ash and magnetite showed that the probable error E value of separation is 0.06-0.08 t/m3.

Jan 1, 2009

By Steve J. Czehura

The Butte quartz monzonite is the host rock for early porphyry copper style mineralization and subsequent mesothermal-epithermal, enargite-gold style veining that transects the district. The east-west Anaconda system veins sustained mining for over a century. They include the Emma, Anaconda-Original, Syndicate, Badger-State and Alice-Rainbow veins, each with strike lengths of more than 3,660-m (12,000-ft) and vertical continuity in excess of 1,370-m (4,500-ft) with mining widths from 1.5- to 15-m (5- to 50-ft). These characteristics are unique to Butte. The incredible dimensions and tenor of these veins have yet to be surpassed and Butte is still touted as being the “Richest Hill on Earth.” The Anaconda Company was formed in 1895 to develop underground copper reserves in the district. It eventually consolidated all operations under one company. Production from underground mining continued through the mid-1970s. Openpit mining in the Berkeley pit began in 1955 with the extraction of supergene ores, along with the remnants of deeper horsetail zones inaccessible to the underground mines.

Jan 1, 2006

By Edward Thomas

Yucca Mountain Overview The U.S. Department of Energy?s Yucca Mountain Project is a geologic repository project designed to receive, handle, package, transport, and emplace spent nuclear fuel and high level radioactive waste. The planned repository would be located in Yucca Mountain on the western edge of the Nevada Test Site, about 90 miles northwest of Las Vegas, Nevada, and would include both surface and subsurface areas. Yucca Mountain rock formations consist of successive layers of volcanic rocks (called tuffs) approximately 14 to 11.5 million years old, formed by eruptions of volcanic calderas to the north. With the volcanic rock the potential for methane emission is not an issue and the subsurface repository is a non-gassy (methane) classification. This paper will provide a summary of the development ventilation system design that provides fresh air for subsurface construction activities, and the emplacement ventilation system design that removes heat generated by the waste packages. The subsurface layout, illustrated in Figure 1, contains 108 emplacement drifts, one Performance Confirmation(PC) observation drift, nine intake/exhaust shafts, and three access ramps. The existing Yucca Mountain facilities, shown in bold lines in Figure 1, include a 7.8 km long, 7.62 m (25 ft) diameter U shaped tunnel that is formed by the North and South Ramps at both ends of the Exploratory Studies Facility (ESF) drift and a 1.5 km long, 5.0 m (16.4 ft) diameter Enhanced Characterization of the Repository Block drift (ECRB) that were constructed from 1994 through 1998. These drifts were used for site characterization activities and have been incorporated into the subsurface repository configuration. The unexcavated perimeter access main and exhaust main drifts are typically 7.62 m (25 ft) diameter TBM excavations and the emplacement drifts are 5.5 m (18 ft) diameter TBM excavations. The turnouts leading into the emplacement drifts are to be excavated by either mechanical, or drill and blast methods and serve as the launch chambers for the emplacement drift TBM excavations.

By R. V. Ramani, C. J. Bise

INTRODUCTION Classification of coal seams as thin, medium, and thick is both subjective and relative and is more a reflection of the statistical mode of the thicknesses en- countered in a mining region. A geological factor more precisely understood as defined than thickness is the inclination of the seams to the horizontal, commonly referred to as the pitch or the dip of the seam. Thick and steeply pitching seams present far more challenges to the ingenuity of the mining men to devise methods for their extraction than the thick and less steeply inclined ones. In a marginal case, where a thick coal seam may be minable by surface or underground methods, the decision bears a close relationship to the technological developments in the mining scene. Near surface thick coal seams are a special gift of nature and are not as wide- spread as the ones that call for the application of under- ground methods. Recent advancements in surface mining equipment have made it possible to surface mine to great depths. Stripping ratios of 30: 1 (cu yd of over- burden removed per ton of coal) have been achieved. The extraction of thick seams which preclude the use of surface methods is the concern of this chapter. Specifically, the objective here is to outline the special technological factors in underground mining of thick coal seams and to illustrate through several case histories the methods that are practiced in the North American continent. For the purposes of this chapter, a thick seam is defined as one which is not readily minable with currently available equipment without modifications to the extraction method or the equipment. At the present time, a thickness of 4.8 m (16 ft) can be considered as the lower limit, although developments in equipment and methods can be expected to push this limit upwards. The data for the case histories were collected from two extended mine visits in 1975 and 1978, and from other published accounts of the mines visited. Reference is drawn particularly to reports by Bise, Ramani, and Stefanko (1976) and Rarnani and Kenzy (1979). THICK SEAM MINING METHODS The various methods of mining thick seams can generally be grouped into three major categories: full face methods, where the entire thickness of the seam is re- covered in a single pass; slicing methods, where the seam is extracted to its full thickness by horizontal or inclined slices either in an ascending or descending order; and caving methods, where the seam is undercut and the en- tire coal seam is recovered by caving the top coal into the excavated cut, or some variations of the basic sub- level caving method. As shown in Table 1, in each of these methods, the coal is removed by either room-and-pillar or longwall methods. Hydraulic mining and transport of the coal in open flumes or in pipelines are also practiced. Addition- ally, the void created by the removal of coal may be filled with a packing material (stowing) except in the caving methods. The pitch (dip) of the seam, particularly when it is greater than 0.26 rad (150), imposes severe operational limitations on mobile equipment. A more detailed general discussion of the methods can be found in Bise et al. (1976) and Vorobjev and Deshmukh (1964). Specific discussion on the many variations of the three basic methods can be found in the papers presented at the international symposia that were held in

Jan 1, 1982

Within the research project "Mine Development" funded by the "Austrian Fonds zur Forderung der wissenschaftlichen Forschung (FWF) " (funds for scientific research) between 1991 and 1993 150 underground hardrock mines in Europe, Northern America, Australia and Japan have been visited to analyze their general design and layout. The main aim of the project was to develop strategies for accessing new underground hardrock mines and to establish a mine planning database. The investigation included mines in high developed countries only, with a comparable labor cost situation. This paper presents the results of one part of the project, which deals with investigations into the influence of different parameters on the design of the primary access for a mine.

Jan 1, 1995

By Michael Taylor, Thomas W. BoBo

Currently two of the most important characteristics of construction aggregates are (a) the particle size distribution (psd) and (b) the “shape” of the aggregate particles. The long established test methods and standards for these properties require substantial resources and most suppliers can take samples and conduct tests at intervals measured in days (psd) or even months (shape). Furthermore these tests require time: so the results are available only after material has been stockpiled or shipped. In the rare cases where problems are found the out-of-spec material has often been shipped to points unknown. There are substantial advantages to be obtained if the psd and other geometrical properties could be obtained from the material as it moves through the production processes and if the results could be reported back within seconds or minutes to Plant Control Managers. This paper describes a single on-line system used to evaluate production of crushed material in a production quarry. The system consists of an enclosure (containing the camera and lighting etc.) mounted over a production belt. Images are fed by fiber optic cable to a nearby control room where the data are analyzed; stored; displayed; and made available for integration into a process control system. Numerous forms of display can be created according to the needs of the producer. Once programmed by an automation engineer all functions of operation are fully automated. The system has permitted over 400 tests per hour with a feed back time less than 2 seconds. Sufficient geometrical measurements are made so that many different “shape” factors can be computed on a similar time scale. The paper summarizes the results from approximately 100 shifts of about 8 hours each and compares the imaging method with the current standard hand methods. Study of the data generated showed that, when combined with additional plant information, the system can be used to generate additional useful control information.

Jan 1, 2005

By K. M. Kim

An analysis was conducted to determine the effects of blasting on slope stability and downstream comminution processes. To investigate these effects, the extent of blast-induced rock damage and the magnitude of induced stress were examined. This analysis showed that damage may extend up to 500 m (1 MPa, tensile strength) into the rock mass, a distance that is sufficient to have an impact on the pitscale slope over the long term. In addition, the damage zone was calculated using the assumption that compressive waves are the primary agent in microfracturing during blast fragmentation. The calculated damage zone — up to 2.2 m (43 MPa, rock mass compressive strength) — indicates that microfracturing can occur throughout 20-50% of the entire rock mass in the blasting area, depending on the blast geometry, burden and spacing. Finally, an economic analysis was conducted by comparing two assumed blasts in a copper mine. The change in energy required for crushing and grinding was demonstrated using Bond’s law after increasing the blast energy from 180 kcal/t to 350 kcal/t. A total cost saving of 13.3% ($9.4M) was achieved with the increase. However, the benefits of blast-induced microfracturing must be balanced against the potential impacts to slope stability to ensure safe conditions, a top priority in mining operations.

Jan 1, 2014

By G. A. Doyle

The quality of water in mine pit lakes depends in part on the physical limnology (Le. stratification, turnover, and development of anoxic conditions with depth) of the lake. Limnologic data collected from four existing pit lakes indicate that pit lakes develop a thermocline, or temperature stratification, in the upper 10m to 30 m of the water column. Two of the pit lakes (26 m and 55 m deep) undergo seasonal turnover of the entire water column, whereas two deeper pit lakes (110 m and 240 m) undergo seasonal turnover of only the upper portion of the water column. In the deeper lakes, seasonal mixing does not extend through the entire water column and a distinct chemocline develops with depth.

Jan 1, 1996

By R. Fuenzalida

Since 2007, a number of Multivariable Predictive Control (MPC) Applications have been implemented on SAG mills, among others, within the Kairos Mining Concentrator Automation Program using ?Profit Controller?? and other tools comprising the ?Profit Suite??. Along this journey, several interesting and challenging issues related to SAG mill operation and control have been faced, which are relevant to be shared with the Mineral Processing community. These advanced control applications have an operational objective whose goal is to increase marginal profit on the concentrator, together with increasing mill stability. In regard to this objective, the issues to be presented and described are in direct relationship with ?Profit Controller? features and the SAG role; they are also stated and linked to get the most of the mill. Some conclusions and findings are also presented, leading to recommended practices on how to use the controller. These findings have also lead us to decide further actions to be taken on new applications to deploy and also on devising and implementing some complementary components to increase robustness of the overall automation solution, as well as reducing the need for operator intervention.

Jan 1, 2012

By Dennis Molvik, Omar Fulton, Chris D. Breeds, Don Gonzales

This paper presents and describes the South Interceptor Parallel Phase III Contract C93012C, which involved construction of a nominal 2.7 m (9-ft) finished diameter sewer conveyance using both pipe jacking and conventional tunneling methods. Earth Pressure Balance (EPB) excavation was required to minimize the potential for settlement beneath a main rail line, overpass, sensitive wetland, areas of contaminated soils, and nearby structures. Ground conditions predicted in the Geotechnical Baseline Report included low plasticity, clayey silt (40 to 10%) and silty sand (60–90%) with pieces of wood such as logs, stumps, branches and other tree fragments. Soil cover ranged from 2.7 m (9-ft) to 5.4 m (18-ft) over the tunnel crown with a groundwater table between 1.5 m (5-ft) and 3.7 m (12-ft) deep.

Jan 1, 2003

By Joseph Goessling, Mark Kroncke, James Parkes

The I-35 Capital Expressway (CapEx) Central Drainage Tunnels will serve as a stormwater collection system for the forthcoming I-35 Capital Express Central reconstruction project through downtown Austin, Texas. The schematic level concept design included three tunnels, 10 to 14 ft ID, totaling 26,000 LF. Constructability reviews during design development indicated issues with the concept design including phasing of construction, conicts with future retaining walls, staging area concerns, and signicant mixed face tunneling. The design was updated to mitigate these risks. The revised design includes two tunnels, both 22-ft ID and totaling 33,000 LF, that will be mined almost entirely in rock.

Jun 23, 2024

By J. D. Miller, C. L. Lin

In the processing industries, it is well known that particle shape is an important factor which determines the behavior of particulate systems. For example, system properties of technological significance including rheology, suspension stability, agglomeration, packing, permeability…etc, are affected by particle shape. In this regard, characterization and analysis of particle shape is essential for more detailed understanding and improved development of particulate processes. In general, it is clear that the behavior of these systems depends on the statistical characteristics of particle shape. Remarkably few techniques exist to predict the mechanical and hydrodynamic behavior of an irregularly shaped particle or a population of irregularly shaped particles for that matter. The lack of models and correlations can be attributed to the wide variety and complexity of particle shapes, the difficulty of defining shape descriptors suitable for modeling, the limitations of measuring shape, and the lack of classifying techniques to characterize particle shape. In this paper, we present information on how 3D particle shape can be measured, characterized, and analyzed using cone-beam X-ray microtomography (XMT).

Jan 1, 2005

By K. Grubaugh

Ghana’s physiographic and geologic features are the basis for its long mining history. The Gold Coast colony has been a significant producer of gold. The gold of the Akan forest (Ghana) was a terminus for caravans that plied Saharan trade routes. Now it also produces significant quantities of manganese, bauxite, and diamonds In addition, the country produces kaolinite, silica for glass, salt, and both aggregate and dimensioned stone. Most secondary minerals are consumed locally but some amounts do find international markets. Ghana revised the mining laws and regulations in 1986. These revised laws dramatically increased gold production and improved the country’s economy. The success of these laws spawned imitators in other African states such as Cote d’Ivoire, Mali, and Burkina Faso. Representatives of these countries claim Ghana was their model. Environmental regulations exist but an intensive adversarial atmosphere is lacking. Ghana has also offered the mining industry incentives like accelerated depreciation rates and exemption from import duties on related supplies and capital equipment. The country has also pursued an aggressive policy to restore the nation’s business infrastructure.

Jan 1, 2001

By N. Ward

The Gualcamayo Mine is located in the Andes Mountains north of San Juan, Argentina (Figure 1). A property of Yamana Gold Inc, it declared commercial production in July 2009 and has a total mineral reserve and resource base of approximately 88,000 kg of gold. Crushing operations for the open-pit mine are located in a 13,500 m3 underground cavern with a ceiling height of 22 m. More than 3,600 m of tunnels are used to access the cavern and convey the ore. The Project as described in this paper relates to the design and construction of the Main Cavern, Conveyor System Exit Tunnel, the Mechanical System Access Tunnels, and two 4.20 m diameter shafts (Ore Pass #1 and Ore Pass #2) as shown in Figure 2. [ ] Preliminary engineering for the Project was performed by Hatch Chile. Rizzo Associates Argentina, S.A., a division of Paul C. Rizzo Associates, Inc (Rizzo) was contracted to provide geomechanical and geotechnical support for the construction of the access tunnel system and geomechanical design and construction supervision for the cavern and shafts.

Jan 1, 2011