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By Christopher Laughton, Michael P. Bruen

At Fermilab, a 4000-ft long underground complex has recently been constructed for a high-energy physics experiment. The complex is sited up to 350 ft, below grade principally in bedrock. The rock excavations were mined by TBM and drill and blast methods and supported by a combination of rock bolts, dowels and shotcrete. Water control was achieved using a combination of pre- and post-excavation grouting, drainage systems, drip shielding and air desiccation measures.

Jan 1, 2003

By Drew Bazil, David Smith, Matteo Ferrucci, David Pittman

The Gateway program will provide additional rail capacity between New Jersey and Manhattan. This paper describes how a 70-foot-deep section of cut and cover tunnel was designed to directly support future high-rise towers. The tunnel will link previously completed tunnel sections under Hudson Yards to future tunnels under the Hudson River. The design aims to minimize constraints on future overbuild and future tunnels, while maximizing constructability within a small worksite. The tunnel will pass under the High Line elevated walkway, next to an active rail yard, and close to a subway tunnel. The design was developed by a tri-venture of WSP, STV and AECOM. WSP led the design of major underground works; STV designed utility relocations and the underpinning concept for the High Line; and AECOM designed temporary in-tunnel systems. Construction is expected to start in 2023.

Jun 13, 2023

By Bernd Hagenah, Petr Pospisil, Colin Santangelo

This paper explores the profound implications of high-speed train operation on tunnel planning, specifically investigating ongoing high-speed rail projects in California and Texas. The paper delves into the crucial considerations for designing high-speed rail tunnels, including selecting tunnel sections based on aerodynamic factors, which impacttraction power requirements and pressure comfort. The paper also examines the need for emergency stations, maintenance access, and comprehensive safety and rescue concepts to address train incidents. Drawing from international high-speed rail projects, it shares valuable experiences and lessons learned to promote efficient and secure tunnel designs for high-speed train operations.

Jun 23, 2024

By James R. Hindman

Vermiculite is the mineralogical name generally applied to a group of hydrated, trioctahedral ferromagnesian aluminum platty or micaceous silicate minerals. In microscopic particles the mineral as mineral is differentiated from montmorillonite by a higher Si:AI ratio of approximately 3:l and a higher layer charge and higher cation exchange capacities. Commercial vermiculite, the vermiculite which is mined, beneficiated, and discussed in this chapter, is an important industrial mineral which is formed by the alteration of macroscopic particles of biotite and iron-bearing phlogopite. In natural form it has the size and shape of mica, while possessing the ion exchangeable properties of zeolites and some clays. Within the internal structure of vermiculite lie water molecules, which when rapidly heated to high temperature, transform into steam causing the vermiculite particles to increase in volume. This process of thermal exfoliation produces a lightweight product which finds use in various construction products, agriculture, horticulture, and other industrial applications. In exfoliated form it has the low density and biological inertness of expanded perlite, while maintaining a chemically active surface. Most of the uses of vermiculite are for the thermally exfoliated material. In addition, the cation exchange potential of vermiculite and its layer-silicate structure are properties which can be used as the basis for numerous products including intumescent coatings and gaskets, inorganic films, and the treatment of nuclear and other toxic waste. When chemically and physically modified, it possesses some properties common to organoclays and synthetic compounds. In high purity concentrates and manufactured products, these properties can be altered and optimized in applications to produce superior performance. GEOLOGY Mineralogy Vermiculite was first described as a mineral by Thomas H. Webb in 1824. Webb believed vermiculite to be a variety of talc and described its diagnostic property of thermal exfoliation thusly: "If subjected to the flame of a blowpipe, or that of a common lamp, it expands and shoots out into a variety of fanciful forms, resembling most generally small worms having the vermicular motion exact." Observing that with one exception, all commercial vermiculite has formed by the alteration of iron-bearing phlogopite, a simple definition of vermiculite might be the alteration product of trioctahedral micas, macroscopic particles of which display marked exfoliation when heated rapidly to temperatures above 374°C (the critical temperature of water). The first vermiculite described was found near Worcester, MA, but it was later pointed out by Brush (1866) that vermiculite had been known for some time in Japan as a children's novelty. Because the techniques for mineral analysis were somewhat primitive com- pared to those routinely available today, and because the structure and crystal chemistry of the micas and related minerals were not widely understood, the early literature generated at least 20 "new" minerals which were nothing more than variations in the color and chemistry displayed by vermiculite. Trade names such as Dugarlite, Mandolitem, Strong-LiteTM, and Zonolitem are sometimes used to denote commercial vermiculite, thermally exfoliated vermiculite and their products. Vermiculite particles resemble mica and vary in color from colorless through tan and green to black, depending on the chemical composition. Most physical and optical properties are close to those of biotite, with perfect basal cleavage, hardness between 1.5 and 2.5 Mohs, and specific gravity between 2.2 to 2.8. Fine-sized particles will feel talcose, especially when wet. However, for commercial vermiculite the diagnostic test is that of thermal exfoliation. Vermiculite can display a wide range of compositions, depending on the composition of the original mica and the change of chemistry during weathering and ion exchange. Chemical data for some commercial vermiculites are given in [Table 1]. There are numerous analyses for vermiculite given in the literature, and the analyses of vermiculites from commercial deposits will fall within the range indicated by the average analysis in the table. Many analyses separate the adsorbed water (H2OP) from crystalline water and water as hydroxyl (H20+). The basis of separation of adsorbed water is generally considered to be 100°C. However, hydrate water within the vermiculite interlayer begins to be lost at 75°C and lower. Therefore, measured water content and loss on ignition are combined in the table as H20[total].

Jan 1, 1994

By Christopher J. Bise

The potential of the coal reserves in the western United States for meeting future energy needs has been recognized for quite some time. However, two of the major constraints which have tended to limit the development of these reserves which can only be deep-mined are the great thicknesses of the coal seams encountered and their high pitch. Although new mining methods may need to be developed to recover these reserves, at least in the short- term the industry has to incorporate presently available equipment which were not originally designed for thick-seam mining. The purpose of this paper is to present an analysis of the various equipment that are in use today and their possible application to thick-seam mining. The paper also addresses the various ground control and safety considerations that are unique to thick-seam extraction.

Jan 1, 1981

By C. S. Simons

The aphorism that provided the title of this paper is probably a couple of hundred years old, but it still expresses a fundamental truth in the metals industry. This truth will be illustrated through a brief review of the major developments in the extractive metallurgy of the oxidized ores of nickel - the "laterite" ores. While the details to be discussed are for the most part specific to nickel, a close parallel with other commodities - particularly in recent years - will be apparent even to those whose interest in nickel itself is slight. Thus it is hoped that this paper will be stimulating, at the least, to anyone who is concerned with the implementation of process improvement, "Invention" in the present context means any change from "conventional" process technology that shows a reasonable chance of reducing costs, increasing revenues, or both, in the production of a commodity. This can be anything from a simple rearrangement of flowsheet steps to a completely different basis for processing. And the result may reduce costs by more efficient use of energy or labor or reagents; may increase revenues by better recovery of the primary product or by introducing the recovery of previously ignored by-products; may insure sales volume (and thereby cash flow) through higher product purity or an improved product form. "Necessity" is the perceived need to attain at least one of these classes of results. This perception of necessity, however, varies widely from management to management and from project to project.

Jan 1, 1983

By J. R. Klaehn, M. Shi, T. E. Lister, L. A. Diaz, J. S. McNally

Since 2019, approximately two dozen international battery recycling companies have been operating at the commercial or pilot scale [1]. However, current process capacity does not exceed 100,000 tons of end-of-life (EOL) lithium-ion batteries (LIB) per year, and the current recycling rate is only about 5% in North America [2-3]. Recycling metals from EOL LIBs is not only essential to waste minimization and environmental stewardship, but also a source of critical materials, which can contribute towards supply chain stabilization. LIB recycling can be roughly divided into three categories: direct recycling, pyrometallurgy, and hydrometallurgy. Direct recycling seeks to retain as much of the manufactured effort with minimum chemical processing [4]. The evolution of battery designs and chemical compositions are challenges to this approach [5-6]. Pyrometallurgical processes are robust and flexible allowing a broad spectrum of batteries with minimum pre-processing requirements. Some of the matrix issues are solved through combustion of some constituents. Smelting is strongly tied to fossil energy and air emissions are a concern. In addition, pyrometallurgical processes are not stand alone, as hydrometallurgical refining normally required to separate and recover the metals of interest (Co, Ni, and Cu) from the produced alloy and Li from the slag [7]. Hydrometallurgical processes can be highly selective and efficient in recovering high purity materials [8]. In general, hydrometallurgical processes are considered cleaner and less costly than high temperature processes [4,9-10]. Extensive chemical consumption and waste generation significantly increase the operating costs and overall environmental impact of the hydrometallurgical processes [11]. Leaching of metals from LIBs is dominated by the mixture of sulfuric acid (1 to 4 M H2SO4) and hydrogen peroxide (1 to 15 wt.% H2O2) [10]. Although organic acids have been tested as lower environmental impact alternatives, the reported pulp density operations are low < 60 g/L [10-11]. For the H2SO4/H2O2 leachates, high leaching efficiencies >90% are reported for Co, Ni, Mn, and Li from cathode materials at temperatures over 40 ⁰C and pulp densities between 30 to 200 g/L [9-10]. H2O2 acts as reducing agent to convert Co+3 and Mn+4 into their soluble forms, Co+2 and Mn+2 [12]. Despite the claims of H2O2 being a clean reducing agent [13], production of H2O2 has significant environmental impacts as determined by life-cycle analyses [13-14]. Moreover, the costs and risks associated with H2O2 transportation and storage cannot be ignored [15].

Mar 2, 2022

By A. K. Fallaw, D. L. Taylor, G. Wang, L. R. Moore, S. Dobson, C. B. Parkinson

"Over the years, the decline of high grade ores have become an increasing problem in the global mining industry. As such, techniques and chemistries must change in order to continue to meet the market demand and quality. Reverse cationic flotation of quartz and silicates is one of the most important techniques for generating the industry standard product from minerals such as iron and phosphate ores. Amine collectors are the global standard in such processes. However, as the ore quality continues to decline so must the chemistry change to meet the change in ore composition. This paper will focus on the introduction and full scale application of a novel amine collector towards a cleaner flotation process in phosphate beneficiation with Crago process. The results suggests the collector is capable of improving the phosphate recovery, in this cleaner circuit, to approximately 94% with minimal sensitivity to the everyday changes in feed grade.INTRODUCTION The days of mining high grade minerals are long gone, but the demand continues to increase. Phosphate ore, for example, is most dominantly demanded from the agriculture industry as a fertilizer component (i.e. diammonium phosphate, DAP) (FAO, 2014). Some literature suggests that global food production must increase by approximately 70% by 2050 (Cordell, 2009). It is also suggested that the peak global phosphorus production will occur around the year 2033, which is the period at which the easily accessible reserves have been depleted. Currently, phosphorus is commonly mined with a BPL (Bone Phosphate of Lime) concentration of 12-20% and a remainder typically being gangue minerals such as silica, clays, metal oxides, calcareous minerals, and carbonaceous minerals. These gangue components can lead to various negative processing and utilization consequences. Calcium, from carbonaceous minerals, is problematic due to the elevated levels of sulfuric acid required to convert the phosphate rock to the acid form (SRI Consulting, 2009). Calcium can also lead to elevated dosages of flotation reagents due to the desire of the fatty acid to coordinate to calcium minerals. Carbonate leads to increased levels of foam during the wet acid process. Silica is associated with the level of insols (acid insolubles), which must be less than 10% in the final concentrate that will be transferred to the chemical plant for acidification. Phosphate ore can generally be classified as carbonaceous or siliceous (El-Shall, 2003). Siliceous ores are commonly processed through various sizing steps followed by multi-staged flotation (Figure 1) (FIPR, 2014 & Güven, 2010). Though the higher grade phosphate pebble is declining, many mines are still able to size good enough to produce some amount of such pebble. Unlike most metal flotation processes where grinding is a necessity for an optimal process, Florida phosphate flotation does not generally require aggressive grinding and can typically operate at 0.1-1.0 mm. The rougher flotation step applies pH modification to achieve the optimal pH of 8.8-9.3 followed by conditioning with a fatty acid type collector, which builds a hydrophobic waxy layer on the surface of the particle to assist in the flotation. This generally achieves higher than 85% recovery of a product with 50-60% BPL and 15-30% insols. Unfortunately, DAP production generally requires 3.5 tons of phosphate rock containing greater than 63% BPL to produce 1 ton of phosphoric acid (ArgusMedia, 2014). Thus, further purification is required to achieve the grade by the chemical plant for fertilizer production. After the fatty acid is scrubbed off the phosphate particles using sulfuric acid (pH 2.5-3.5), the pH is generally operationally readjusted to 6.5-7.2 by washing with “fresh” water. A second collector is applied prior to the cleaner, which is a reverse cationic flotation process. This collector is typically a cationic amine based reagent, which should have an affinity for silica containing mineral"

Jan 1, 2015

By Gilbert Sauriol

The mining complex, which the Mines Gaspé division of Noranda Mines Limited has operated in Murdochville since 1954, includes open pit and underground mines, two mills, one leaching plant and a smelter. The under- ground mining uses predominantly a large scale room and pillar method, rooms 15 m wide, 30 m high and 300 m long being common. Ore production is effected by 4.5 m3 front-end loaders and 32-tonne trucks powered respectively by 225 and 325 kW diesels. Daily dust and gas readings show that air quality can be maintained at an acceptable level with much less ventilation than that normally specified. This paper emphasizes the point that air requirements should be based on Air Quality Standards, thus allowing an operation to benefit from favourable conditions or from improvements such as exhaust treatment, fuel alteration, etc.

Jan 1, 1983

By J. D. Miller

The fossil resins of certain western coals are of significance and of sufficient value as a chemical commodity to justify a fossil resin industry. At the present time these valuable fossil resin resources, worth more than $0.50/lb as a chemical commodity, are being burned as fuel for electric power generation. This waste of our fossil resin resources corresponds to a loss in revenue of $200 million per year -equivalent to the value of the coal itself! Improved process technology for the recovery of fossil resin is under development and includes selective flotation of fossil resin from fine coal streams and solvent refining of the fossil resin flotation concentrate to produce a premium resin product. The most recent developments in process technologies are discussed with respect to separation efficiency and product quality. It is clear that the development of a fossil resin industry should not be limited by process technology.

Jan 1, 1994

Underground mining has the potential to be one of the more dangerous industries in the United States and the world. Following recent disasters in Sago, WV; Darby, KY, and Crandall Canyon, UT, the mining industry was reminded of the need for a system to allow trapped miners awaiting rescue to survive following a disaster. To address this need, Battelle has developed a Mine Barrier Survival System (MBSS) that surpasses all current technologies and sets a new standard for keeping miners alive in the event of a fire, flood, explosion or collapse. The MBSS creates a temporary refuge for miners who cannot escape by using inflatable barriers and a post-fire atmosphere scrubbing system to define the ?safe haven? and remove CO2 and CO while replacing oxygen and providing heat. Current personal-protective systems in use are designed to provide breathing air for only a few hours when, realistically, it may take days for rescue teams to reach trapped miners. Battelle?s MBSS is designed to aid up to 15 miners for four days.

Jan 1, 2008

By Charles N. Alpers, D. Kirk Nordstorm

A variety of approaches have been used in the recent literature for the estimation of pre-mining (or natural background) metal concentrations in areas affected by mining. The following is a list of some of these approaches: (1) historical and anecdotal data, (2) remote analogues (other similarly mineralized areas), (3) proximal analogues (nearby mineralized areas), (4) sediment sampling (streambeds, lakes, estuaries, floodplain deposits, and soil profiles), (5) stable isotopes (hydrogen, oxygen, sulfur, and carbon), (6) geochemical modeling (forward, equilibrium-based), (7) geochemical modeling (forward, kinetic- and transport-based, and inverse), (8) statistical analyses, (9) mass balance on oxygen flux, (10) mass balance with age determination of weathered material. Examples of each approach are described, and the strengths and limitations of each approach are discussed.

Jan 1, 2000

By J. K. Whyatt

In situ stress on the scale of a tunnel or mine may be distorted by geologic structures. The resulting variations of in situ stress have a direct bearing on the potential for mining-induced seismicity. New evidence from the Lucky Friday Mine collected by U.S. Bureau of Mines researchers, as well as a review of case studies, demonstrates that in situ stress variations affect the spatial distribution of mining-induced seismicity. Although overcore stress measurements have been useful in these studies, they are too expensive and, depending on conditions, may be too difficult, to use routinely in mapping stress variations. However, information from borehole and raisebore breakouts; deformation of mine openings; and patterns of seismicity, ground control problems, and rock burst damage can be used to build a stress database. This database can then be used in con-junction with maps of mine structure and geology and models of rock mass behavior to build a map of in situ stress variations. Such a map provides a means to anticipate patterns of mining-induced seismicity that are likely to be encountered and, hence, provide a means for planning appropriate measures to ameliorate rock-burst hazards.

Jan 1, 1995

By P. Zhang

This paper gives a review of promising technologies for phosphate processing, and covers flotation, analysis and process control, as well as tailings treatment and utilization. Air bubbles of less than a µm in size, combined with relatively large bubbles, have been demonstrated, both in the lab and on a pilot scale, to improve flotation dramatically, by reducing reagent use while improving product grade. Innovative use of polymers has allowed rapid dewatering of fine tailings with a final product that does not segregate. The first online laser-induced breakdown spectroscopy (LIBS) analyzer was created, allowing rapid analysis of wet samples using the laser technology. Many large commercial projects are successfully pursuing the utilization of phosphogypsum.

Feb 1, 2012

By M. K. Han, K. N. Han, P. B. Queneau, W. J. Dawson

The development and scale up of hydrothermal synthesis processes for manufacture of high performance materials is discussed. Traditional hydrometallurgical processes are reviewed, leading into a discussion of process development concerns for manufacture of modern materials. Three case studies are presented, including a piezoelectric ceramic, barium titanate for multiyear capacitors, and high purity chromium metal. Factors for selection of reactor design are presented, as well as results of scale-up studies on the three products.

Jan 1, 1993

By Keith E. Dyas, John Nelson, Ronald T. Johnson

GENERAL DESCRIPTION The Bruce mine of Cyprus Mines Corp. is located in Bagdad, AZ. The mining method used is open cut-and-fill. Of the annual production of 81 647 t (90,000 st), approximately 83% is taken from load-haul-dump (LHD) stopes and the balance from slusher stopes. All ore is produced from the area between the 1250 level and the 2300 level. The average travel time from the shaft pocket to the stope is approximately 5 min. GENERAL ORE BODY REQUIREMENTS AND LIMITATIONS Size, Shape, and Dip The Bruce ore body occurs in quartz-sericite schist with Dick rhyolite on the footwall and andesite on the hanging wall. Diabase dikes are found in the hanging wall; there is also a dike coming off the footwall and crosscutting the ore body. All of the rock types are of the Precambrian Yavapai series and have been subjected to regional metamorphism. A composite of the ore body is given in Fig. 1. The deposit is of massive sulfides occurring as a steeply dipping replacement body. On the upper levels the ore is veinlike with widths from 0.6 to 4.6 m (2 to 15 ft), dipping at 1.4 to 1.5 rad (80° to 85°). On the lower levels the ore is dipping from I to 1.2 rad (60° to 70°) with widths from 3 to 16.8 m (10 to 55 ft). The strike length varies between 107 to 183 m (350 to 600 ft). The rhyolite footwall generally has a knife-edge contact with the massive sulfides. The exceptions to this are the upper levels where there is a 1.5 to 3 m (5 to 10 ft) band of silicified sericite schist between the sulfides and the rhyolite. In the southern part of the ore body the hanging wall is tuffaceous andesite and andesite. In this area the contact is generally sharp and easy to follow. However, to the north there is a large chlorite schist zone that crosscuts the bedding and comes in contact with the massive sulfides. This is apparently due to hydrothermal alteration of the andesite. The chlorite schist is highly mineralized with chalcopyrite and pyrite and quite often forms economic pockets of ore. In the massive sulfides the chief ore minerals are sphalerite and chalcopyrite. Pyrite is the predominant sulfide with considerable pyrrhotite throughout. Bright arsenopyrite ouhedrons in fine grain massive sulfides are quite common. Occasionally small amounts of galena are seen, usually near the foot or hanging wall contacts. On rare occasions tennanite is associated with massive arsenopyrite. Minor amounts of quartz, calcite, and un¬replaced remnants of sericite schist occur, but essentially pyrite is the gangue in which the ore minerals occur. The ore values are in excess of 3.5% copper and 12.5% zinc with some silver and rare gold as byproducts. Ground Conditions The massive sulfides are generally self-supporting. One exception is in the 1850 stope where the ore body is 9 to 11 m (30 to 55 ft) wide and 152 m (500 ft) long. There are flat to shallow dipping slips and seams in the ore, creating extremely blocky ground. For support, old 25.4-mm (1-in.) hoist ropes were installed tensioned to 27 t (30 st), and then cement grouted over the entire length in longholes [14 to 15 in (40 to 50 ft) in length) drilled on 3-m (10-ft) centers from the level above. This has tied the formation together very successfully and virtually eliminated the blocky ground condition. Both the hanging wall and footwall are quite shaley in some areas. Reasons for Adopting Trackless Open Cut-and-Fill Methods First, any method other than open cut-and-fill would have caused too much dilution. The use of rubber-tired mining equipment in the pro¬duction stopes requires a footwall ramp. The inclines in ore will be mined out, so this ramp in the footwall will provide access to and from the stopes (Fig. 2). This incline is very expensive, but necessary to convert existing stopes to LHD mining. &apos;The final cost of ore mined by the LHD machines has not been determined. As of 1972, tons per manshift in the 2150 stope-the only one to complete a full cut-had increased from 7.58 t (8.36 st) to 12.83 t (14.14

Jan 1, 1982

By Y. V. Vasylchuk

This paper presents an algorithm for optimizing the classification of surface mine material subject to excavating constraints. High-resolution expected profit models are input and optimized to classification maps subject to site-specific rectangular excavating constraints. This optimization problem defies traditional closed-form analytical solutions; a practical heuristic algorithm has been developed to quickly determine the optimal final destination for the material subject to realistic constraints. The optimization is fast and generates results that achieve up to 98–99% of the total expected profit achieved with free selection. This algorithm provides a fast viable option for practical application in short-term grade control and in managing multiple realizations in long-term resource estimation.

By Gordon F. Revey

In underground construction and mining work, situations occasionally occur where hard rock or concrete must be excavated at locations near critical structures or utilities. Fearing damage from blasting, contractors and engineers often explore the viability of using mechanical methods or expansive concrete to facilitate the excavation work. However, for moderate to large excavations, the prolonged duration and high cost of using these methods is often impractical. In these situations, under the right conditions, controlled blasting and blast-management methods can be used to speedup the work and lessen costs. The process of determining whether or not blasting is practical is often complex, particularly when risks are high. In this paper, general methods of conducting blasting risk evaluations and outlined and considerations for blast design and risk management are reviewed. This paper also includes three blasting case histories demonstrating how these techniques were used at recent projects. In the first case, a cautious blasting program was developed to facilitate the removal of concrete and rock within a large section of an active mineshaft. The second case involved critical blasting to excavate a dry lake-tap connection between a tunnel and a shaft at the Southern Nevada Water Intake No. 2 project in Henderson, Nevada. The third case history describes how novel blasting methods were used to carefully drop a 2,721,500-kg (6,000,000-lb) concrete caisson into a1.2-m (4-ft) rock socket at the Detroit Outfall No. 2 project in Detroit, MI.

Jan 1, 2001

By Ted Klemetti

Roof deterioration in weak moisture-sensitive rock leads to roof falls in coal mines. An observation site was set up in intake air at an underground coal mine in central Ohio to evaluate the time-dependent deterioration of moisture-sensitive roof rock. By periodically collecting and weighing the rock falling from the roof, the National Institute for Occupational Safety and Health (NIOSH) was able to quantify the deterioration of the moisture-sensitive shale roof. The measurements showed that more roof rock is falling in the dry winter months. Movements in an intersection were monitored in order to determine if deformation correlated with seasonal changes in temperature and humidity. The rate of intersection roof-to-floor convergence was found to be cyclical and related to seasonal changes, with more convergence during the months of April through September. At the study site intersection, the roof beam did not show deflection indicating movement most likely due to mine floor deformation. The bolt load also increased in the warmer months before shedding load, possibly due to rock failure. Temperature and relative humidity sensors, placed in holes in the roof show that mine air does not mix with the air in the holes. Consistent saturation levels of relative humidity were measured in the holes and it appears that high levels of moisture may have migrated into the bolt holes from roof shales. A roof sealant applied to a portion of the test roof appears to be preserving the roof and reducing the amount of rock fall into the entry, while the screened area virtually eliminated rock falling from the roof.

Jan 1, 2009

By Stephen F. Munsell

The development of transportation systems for mined materials has historically been characterized by steadily increasing sizes in basic hauling units. This is especially true for open pit mines for which success is dependent upon the economical transportation of vast quantities of material. The depletion of high grade ore reserves has mandated a tremendous increase in the size and complexity of the ore haulage systems necessary for open pit mines, These increased demands were served by rail haulage systems in the early large open pit copper mines while later developed properties opted for the flexibility and lower initial costs of truck haulage. Now, we find the trucks being displaced as large overland belt conveyors tackle the problem of handling these ever larger quantities of low-grade ores with accompanying overburden ratios that can run as high as 10:1 or even 15:1. The basic development of large conveyors with shiftable sections and modular belts has generally taken place overseas, during the last few decades. The coal fields of central Europe proved an ideal testing ground for conveyor innovation because the low density and natural friability of the material created an ideal medium for transporting by belt conveyor. Now these proven ideas are being considered for and implemented into both the soft and hard rock mining industries of the United States.

Jan 1, 1978