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By V. O. Tenorio, K. P. Hague

Mines are constantly trying to improve production processes by optimizing work cycles, reducing operational delays, minimizing costs, controlling equipment utilization, and preventing occupational hazards. Currently, advances in digital mining technologies within the concepts of 5G and Industrial Touch Internet are allowing better control and monitoring of underground mining equipment, with centralized control systems that unify data analysis for proper decision making. A wireless 5G-based platform for controlling and monitoring systems for underground mine operations can be designed over a comprehensive layout in where bandwidth selection, sensor location, Wi-Fi repeaters and power distribution are put together to build a successful supervisory system. In order to confirm the validation of these concepts, a case study is proposed for a medium-sized underground mine with a multi-level network which includes tablets managed by production supervisors, along with other data collection devices installed in semi-autonomous mining equipment, collecting, and distributing data in near-real time, with interconnection to support and services areas on the surface.

Mar 2, 2022

By R. S. Olson

The operation of a series wash thickener-two stage filtration circuit determines the soluble loss in many hydrometallurgical operations A study of this circuit yielded expressions which permit calculation of soluble loss for almost any condition of operation. The soluble loss over a range of the circuit variables is presented to illustrate and evaluate circuit performance, The interrelation of factors affecting filter performance and some of the wash circuit, variables are quantatively described. Filter wash, which is governed by wash zone size, filter pulp level and filter feed pulp density, has the greatest affect on soluble loss. Excepting clothing blinding and flocculation the factors which decrease filter capacity also decrease soluble loss. Repulping with water, under some circumstances, can bean important means of soluble loss reduction. Water for primary filter wash, leach pulp density repulp density and wash thickener underflow density have little effect on soluble loss. The dilution of both o the filter pulps with wash solutions is suggested as a means of reducing soluble loss, and at the same, time, controlling the performance of the filters. Blowback and filter cloth blinding seriously increase soluble loss.

Jan 1, 1962

By Ronald W. May

The Lower Cretaceous McMurray Formation in northern Alberta contains bituminous sands interbedded with other sediments which form the reject encountered during mining operations. Grade prediction is based on a combination of geological interpretation, computer modelling and past mining experience. In addition to estimates for ore, an accurate estimate of "waste" or "reject," are required for Mine Planning. This study investigates the ability of point-kriging using geostatistics, to augment the existing data base of drill-holes in a study area on Syncrude's leases. This approach enables the assessment of potential "worst" case - "best" case scenarios within the context of Mine Planning.

Jan 1, 1985

By Peter W. Lipman

Structural and topographic relief in the Sangre de Cristo Mountains of northern New Mexico provides a remarkable cross section through the recently recognized 23-26 m.y.-old Questa caldera and cogenetic volcanic and plutonic rocks. Although largely eroded, remnants of an ash-flow sheet of silicic-alkalic rhyolite and associated more mafic lavas of the Latir volcanic field are preserved as far as 45 km beyond the source caldera. Within the caldera, the tuff ponded to a thickness of 2-3 km and enclosed chaotic megabreccia fragments which slumped from the caldera walls. At the time of ash-flow eruption, the volcanic field was severely deformed along northwest-trending faults related to the Miocene Rio Grande rift, with most intense deformation occurring within the caldera. Strata were steeply tilted and locally overturned along presumably listric faults. Ash- flow tuffs locally underwent secondary flowage over concurrently developing fault scarps and accumulated within structural basins as rheoignimbritic lava flows. Cogenetic batholithic granitic rocks, exposed over an area of 20 x 35 km, range from mesozonal quartz monzonite to epizonal porphyritic granite and aplite, with the shallower and more silicic phases most abundant within the caldera. Compositionally and texturally distinct granitic phases define a highly evolved resurgent intrusion within the caldera, an incomplete ring dike along its southern margin, and a large mass of less fractionated quartz monzonite south of the caldera. A negative Bouguer gravity anomaly is closely confined to the area of ex- posed granitic rocks; it also reflects boundaries of the Questa caldera. The gravity anomaly is interpreted as defining the extent of the underlying batholith, emplaced into lower parts of the volcanic sequence and underlying Precambrian rocks. Paleomagnetic determinations indicate that the granitic rocks were above Curie temperatures at the time of caldera formation and regional listric faulting, yet most are little different in radiometric age from the intensely deformed volcanic rocks. These relations indicate that the batholithic complex represents the source magma body for the volcanic rocks, into which the Questa caldera collapsed, and was largely liquid at the time of regional tectonic disruption. Compositions of the volcanic and plutonic phases changed from early calc-alkaline metaluminous rocks, to weakly peralkaline silicic rhyolite and equivalent afredsonite-acmite granite at the time of the caldera formation, then back to post- caldera calc-riebeckite granitic rocks. Maximum concentrations of alkalis and minor elements such as Rb, Th, U, Nb, Zr, and Y were reached at the time the caldera formed about 25-26 m.y. ago, but the major molybdenum mineralization of the Questa district took place when the late calc-alkaline granitic ring intrusions were emplaced about 23 m.y. ago, along the south margin of the caldera.

Jan 1, 2013

By K. A. Natarajan, S. Usha Padukone

"An industrial waste liquor having high sulfate concentrations was subjected to biological treatment using the sulfate-reducing bacteria (SRB) Desulfovibrio desulfuricans. Toxicity levels of different sulfate, cobalt and nickel concentrations toward growth of the SRB with respect to biological sulfate reduction kinetics was initially established. Optimum sulfate concentration to promote SRB growth amounted to 0.8 - 1 g/L. The strain of D. desulfuricans used in this study initially tolerated up to 4 -5 g/L of sulfate or 50 mg/L of cobalt and nickel, while its tolerance could be further enhanced through adaptation by serial subculturing in the presence of increasing concentrations of sulfate, cobalt and nickel. From the waste liquor, more than 70% of sulfate and 95% of cobalt and nickel could be precipitated as sulfides, using a preadapted strain of D. desulfuricans. Probable mechanisms involving biological sulfide precipitation and metal adsorption onto precipitates and bacterial cells are discussed.IntroductionIndustrial effluents from hydrometallurgical and mineral processing operations often contain high sulfate and metal concentrations posing significant disposal problems, which require urgent solution to avoid serious environmental contamination. In such waste liquors, sulfate and heavy metals such as cobalt, nickel, zinc and iron originate from the chemical or biological oxidation of exposed sulfide minerals. Reduction of sulfate and precipitation of toxic metal ions from industrial wastes is essential from the viewpoint of environmentally acceptable waste disposal and recovery of associated strategic metals.Many of these heavy metals are essential for metabolic activity of bacterial cells at low levels. But they exert toxic effects at concentrations encountered in polluted water. Removal of toxic metals through biological reduction of sulfates from industrial waste waters have been practiced for several decades. Metal remediation through common physicochemical techniques such as oxidation-reduction, chemical precipitation, filtration, electrochemical treatment, evaporation, ion exchange and reverse osmosis processes is expensive and not suitable in the case of voluminous effluents containing complexing organic matter and low metal concentrations. Further, strong and contaminating reagents are used for desorption, resulting in toxic sludge and secondary environmental pollution. Biotechnological approaches can be more efficient and cost effective for detoxification of such effluents. Biotreatment/ bioremoval offers several advantages over conventional chemical and physical treatment technologies, especially for diluted and mixed contaminants. Biological detoxification, which involves the use of microbes to detoxify and degrade environmental contaminants, has received increasing attention in recent years (Iwamoto and Nasu, 2001). In addition, valuable metals can be recovered from metal sulfide sludge (Boonstra et al., 1999)."

Jan 1, 2015

By Jürgen Kretschmann

According to the model of product life cycles, the global coal mining industry is in the stagnation phase. The coal demand of the main consumer, China, has peaked in 2013 and is slowly declining. The Norwegian sovereign wealth fund, the world’s largest, has excluded coal-related companies for ethical reasons. Important players like the UN or the EU have already begun to describe pathways towards decarbonization. Increasing competition between coal mining companies and the mining regions can be expected worldwide if companies want to keep their positions on the global and national coal markets. Companies will focus on the best deposits. European countries like France, Spain, or Germany are only forerunners of this development—their centuries of coal production have been finished. The concept of sustainable development (SD) is fundamentally based on a model of progress where ecological, economic, and social dimensions should be developed equally and positively. But without the idea of competition, the concept of SD is incomplete. Questions arise, such as how can SD be realized on stagnating or declining markets without guarantees for companies “to live forever”? How can SD be a corporate goal in a phase of decline? How can declining mining regions sustainably progress into a better future? The German hard coal mining industry’s lifecycle has ended in 2018 after 60 years of stagnation and decline. As of 2019, all hard coal consumed in Germany will be imported, especially from Colombia, Russia, and South Africa. What has been done in Germany to handle the coal decline in a sustainable way and the lessons learned from this process is described in this paper. It may be useful for mining regions who will face a similar future sooner or later.

By H. Copur

Roadheaders have become widely used in underground mining and tunneling operations because they offer the flexibility to excavate soft- to medium-strength rock formations. A critical issue in successful roadheader application is the ability to develop accurate and reliable estimates of machine production capacity and the associated bit costs. Increased pressure to improve productivity and lower costs in the mining and civil construction industries has been the driving force behind the more wide- spread use of mechanical excavation systems. This has caused both industries to move away from the conventional drill and blast methods. Additional benefits of mechanical mining include improved safety, reduced ground support requirements and fewer personnel. These advantages, coupled with recent enhancements in machine performance and reliability, have resulted in mechanical miners taking a larger share of the rock excavation market. Roadheaders are the most widely used underground partial-face excavation machines for soft- to medium- strength rocks, particularly for sedimentary rocks. They are used for development and production in soft rock mining (main haulage drifts, roadways and crosscuts), particularly in coal, industrial minerals and evaporitic rocks. In civil construction, roadheaders are used to excavate railways, roadways, and sewer and diversion tunnels in soft ground conditions. They are also used to enlarge and rehabilitate underground structures. Their ability to excavate almost any profile opening also makes them attractive to those mining and civil construction projects where various opening sizes and profiles are needed. In addition to their high mobility and versatility roadheaders are generally low capital cost systems com- pared with most other mechanical excavators. Because of higher cutting-power density due to a smaller cutting drum, roadheaders can excavate rocks harder and more abrasive than continuous miners and borers.

Jan 1, 1998

By D. D. Xu

A novel system for the depression of pyrite and the ash-forming minerals has been developed. A metal ion, including but not restricted to Fe+2, is added to form a hydroxide coating on the pyrite or ash-forming mineral. A polymeric depressant is then added to attach to this re-surfaced mineral. Nearly 200 flotation tests with a 11 different coals indicate the effectiveness of this system. Many of the important process variables such as the coal source, frother-collector system, grind size and procedure, pH, metal ion, and depressant type and concentration have been studied.

Jan 1, 1994

By Grant R. Brown

The purpose of this opening paper is to provide an overview of incentives strategies. This overview includes a discussion of the different types of incentives, their advantages and disadvantages and their potential application to the mining setting. Objective The primary objectives of incentive plans are to increase worker (including management) effectiveness and reduce unit labor costs. These plans can be grouped into two major categories: 1) non-financial plans 2) financial plans

Jan 1, 1983

By A. L. Mular

A great deal of effort is being expended by mineral processing engineers to acquire a basic knowledge of modelling and optimization techniques. Stimuli such as immediate process improvement, expanded process understanding, optimal flowsheet design and re-design, and the development of new and better control systems are goals which excite the imagination in terms of increased profits. To reach these goals, process models and efficient optimization strategies, regardless of their purpose, assume an important role. Consequently, few of us can argue that such efforts are of no value. The purpose of this paper is to review empirical modelling methods and optimization strategies which appear to be of value to mineral engineers.

Jan 1, 1972

By V. L. Ketellapper

This paper discusses the technical issues and stakeholder collaborative processes which resulted in achieving a balance between the reclamation of abandoned mine sites, providing affordable housing, and preservation of open space at the French Gulch Site. Through this process, it was discovered that mine site reclamation would need to be conducted in conjunction with two priorities for community sustainable development: providing affordable housing for locals who work in the resort town of Breckenridge, and open space preservation. It was found that conducting these activities concurrently would result in providing resources necessary to complete mine site reclamation. The first phase of the affordable housing development is almost completed. This development resulted in redevelopment of mining impacted lands and was recognized by the U.S. Environmental Protection Agency (EPA) with a National Smart Growth Award in 2002.Negotiations are also underway to preserve the remaining 1,800 acres of land held by the mining company as open space. This transaction will in turn provide resources to address water quality issues associated with mine discharges.

Jan 1, 2004

By Hao Zhang, Mi Zhou, Lichun Jiang, Xihong Zhang

This study investigates the roof stability of underground limestone mining in the presence of stratified joints during the excavation process. An analytical solution is derived to predict the stresses and deformation of underground tunnel structures, with the structure simplified as a double-hinge arch. The accuracy of the analytical model is validated through comparison with finite element modeling results. A parametric study is then conducted to assess the influence of different design parameters on the optimization of tunnel stability during excavation. The results indicate that the best stability of the tunnel can be achieved in engineering practices when the applied load (q) is 5 MPa and the joint inclination angle (θ) is 45°, with the roof span and thickness set at either 12 m and 8 m or 15 m and 10 m. These findings provide valuable design guidance for underground limestone mines with stratified joints.

Oct 18, 2023

By C. Hendricks

This paper is based upon field studies conducted in a western Canadian open pit coal mine. This work has involved the adaptation of microprocessor-based instrumentation to monitor various operating parameters on-board blasthole drills and mining shovels. A review of instrumentation and monitoring methodology will first be presented. Based upon experience from field-based studies, the paper will subsequently focus on the application of monitoring technology within the framework of an integrated Equipment Monitoring System. Such a system will permit the real-time performance evaluation of key equipment involved in surface mille production.

Jan 1, 1991

By F. G. Heivilin

There will be 3 billion people moving into cities by 2050. Permitting is both the biggest obstacle and the biggest opportunity for mining. The problem is not if we have the right minerals, but how we can permit and produce it in a ?Sustainable? manner. A ?Permit? and a ?Sustainable Development Plan? may soon be the same thing. How do we produce the minerals we need with: 1. The lowest possible carbon footprint. 2. Social license from community outreach by being a catalyst and not a problem in a ?Green World.? 3. Enhanced water supply during all stages of production. 4. Meeting requirements of our customers for service, quality, & cost. How important is it to have a complete ?Sustainable Development Program?? First, no plan is complete!!! It is a work in progress subject to continuous improvement. We need to work together to get the results we want. The goal of the world communities is to become carbon neutral by 2050. What is the mining community?s goal? Do we have one???? When a Clorox, Colgate Palmolive, Wal-Mart, Toyota, or Caterpillar buys a product, what are your chances of getting an order without a good program in place? The answer is it will be difficult or impossible shortly and you will be requiring the same thing with your suppliers. This is an opportunity if you are in the lead and it soon will be a necessity for most mining and processing companies requiring much extra effort to catch up. For some mines it was a necessity to get most of the SD plan to get permitted. The number of companies in the extractive industries with a full Sustainable Development Programs is expanding rapidly as shareholder demands for transparency continue to grow.

Feb 27, 2013

By R. Todd Swinderman

"Higher production demands across all bulk handling segments require increased efficiency at the lowest cost of operation, in the safest and most effective manner possible. As conveyor systems become wider, faster and longer, more energy output and more controlled throughput will be needed. Add an increasingly stringent regulatory environment and cost-conscious plant managers must closely review which new equipment and design options align with their long-term goals for the best return on investment (ROI).There are primarily two separate market segments using conveyor belts. One is in process industries such as food, chemicals, paper and powders. Handled in relatively low volumes, the bulk materials that enter these processes are generally of a consistent size and quality. The other market includes mining, coal handling and cement, where the bulk material’s quality and size vary, and the volumes are typically much greater. While both segments face similar issues with safety and environmental control, the properties of the materials handled and the volumes transferred suggest different approaches, with one thing in common: increased belt speeds requiring modern equipment upgrades.Safety at higher belt speedsWith companies recognizing that safety does indeed pay, safety is likely to become a new source of cost reduction. The percentage of mines and processing facilities with a robust safety culture are likely to increase over the next 30 years to the point where it is the norm, not the exception. In most cases, with only a marginal adjustment to the belt speed, operators quickly discover unanticipated problems in existing equipment and workplace safety. These problems are commonly indicated by the larger volume of spillage, increased dust emissions, belt misalignment and more frequent equipment wear or failures."

Jan 7, 2017

By Warder A. Shaver

INTRODUCTION Mine No. 95 of the Consolidation Coal Co., a divi¬sion of Continental Oil Co., is located in Shinnston, WV. Mine No. 95 was opened in January 1967 and has been operating continuously since that time. The mine has 544 hourly and salaried employees. In 1974 this mine was the largest coal producer in West Virginia. Opera¬tions include two longwall sections and eight Marietta Borer continuous miners. Originally there were also two Jeffrey Heliminer continuous miners, but use of these was discontinued in June 1978. Production averages 12 727 t/d (14,000 stpd). Two portals now service the mine with a third portal proposed for 1978. GEOLOGY Mining takes place in the Pittsburgh coal seam which dips 0.04 rad (21h°) northwest. The working seam is steam coal with an average height of 2.2 m (86 in.). Immediately above the seam, the overburden is com¬posed of 6.1 m (20 ft) of shales followed by 6.1 m (20 ft) of weak sandstone and 51.8 (170 ft) of shaley limestone. The shale weathers when exposed to mois¬ture. Surface water has been a problem due to a fire¬clay floor which turns to paste when mixed with water. GENERAL DESCRIPTION The present mining plan for Consol's No. 95 mine has a proposed life of 35 to 40 years. One set of main headings has been driven in the north direction and one set in a western direction. These are the areas in which the majority of the virgin coal lies. The panels are driven off of the mains at 2134 to 3048-m (7,000 to 10,000-ft) intervals. The continuous mining sections are set up 133 x 610 m (600 x 2000 ft). Longwall sections are 259 x 1220 m (850 x 7000 ft). All of these mining sections are retreating uphill. Development is with continuous miners. A Marietta Borer miner is used for the main development work. These miners cut 4.1 m (13 ft 6 in.) wide and 2.1 m (7 ft) high, leaving an arch cut. Along with the arch, a 152.4-mm (6-in.) thick layer of roof coal is left in place to protect the roof from weathering. The combi¬nation of the self-supporting arch and the roof coal al¬lows the entries to be driven 30.5 m (100 ft) without bolting. Full bolting, however, is carried outby the last open crosscut. This bolting is done on 1.5 x 1.5-m (5 x 5-ft) centers using 1.5-m (5-ft) long roof bolts with tandem anchors and 152.4-mm (6-in.) steel washer plates. When needed, crib blocks with a 50.4-mm (2-in.) drill hole are used as supplemental supports. Three-hole steel channel with the ends curved down¬ward to conform to the borer arch may also be used. In the mining sections, a 14 BU loader is used be¬hind the Marietta miner to load two Torkar shuttle cars. These haul to Long-Airdox feeder breakers which load onto a 1.07-m (42-in.) wide conveyor belt. With the exception of the shuttle cars, which use 275-V d-c power, the face equipment operates on 550-V a-c power. The main power line is 7200 V ac. The same loading and hauling equipment is used with the Marietta Borer miner for driving both panel and development entries. In the retreat sections, the same equipment with the exception of the miner is utilized. Because of the advantage of a variable cutting hight, Jeffrey Heliminer ripper-type continuous miners were employed in these retreat sections. For longwall mining the first unit uses an Eickoff EDW 300-L double-drum ranging shearer. Drum di¬ameter is 1.69 m (66 in.) with a drum rotation speed of 45 rpm. The drum is equipped with 48 Carmet 34-L-1 bits. The 300-kW (400-hp) motor operates on 1000 V. Tramming of the shearer head is done through a hydraulically driven 26-mm wide chain. Maximum cutting speed is 7.93 m/min (26 fpm), and maximum tram speed is 12.8 m/min (42 fpm) with an average cutting speed of 3.66 m/min (12 fpm). Web cutting depth is 762 mm (30 in.) and the cutting height is 2.13 m (7 ft). The conveyor width is 686 mm (27 in.). It uses a single chain, 26 mm thick, with flights on 0.91-m (3-ft) spacing. The face conveyor speed is 64.3 m/min (211 fpm) when driven by two 112-kW (150-hp) 1000-V Louis Allis motors through torque convertors. The roof support used is Gullick Dobson chocks [6-legged 77.3 t (85 st) per leg, 463.6 t (510 st) total capacity] with double-acting leg jacks. The hydraulic pressure for the legs is 13.8 MPa (2000 psi), and the hydraulic pressure for rams is 6.8 MPa (1000 psi). The yield valves are set at 57.8 MPa (8500 psi). Each chock weighs 4.09 t (4.5 st). The stage loader is an Eickoff drive, with a 68-kW (90-hp), (00-V Reliance motor. A 26-mm thick single strand chain with flights on 0.6-m (2-ft) centers runs at 75.89 m/min (249 fpm). The stage loader is self-advancing and is connected to the belt tail piece with a special fifth wheel attachment so that the stage loader can advance and guide the tail piece. The hydraulic pressure for the roof support is supplied by two 45-kW (60-hp) Reliance motors op¬erating on 699 V, with 1.26 L/s (20 gpm) constant volume Gullick hydraulic pumps. Each pump services alternate chocks, with the two pressure lines connected at the tailgate by 25.4-mm (1-in.) hydraulic hoses, rated at 27.21 MPa (4000 psi). The 6.8 MPa (1000 psi) pressure rams advance is supplied by a 45-kW (60-hp), 600-V Reliance motor and a 1.26-L/s (20-gpm) con¬stant volume Gullick pump. Return lines are 35.5-mm (1.4-in.) diam hydraulic hoses with rated capacity of 27.21 MPa (4000 psi). The fluid used in the hydraulic system consists of 95% water and 5% Hy-chock fire resistant water soluble oil. Water is stored and mixed in a 6096-L (2000-gal) track-mounted tank and goes to a 655-L (180-gal) reservoir at the pump. The belt conveyor structure is 1.07 m (42 in.) wide with 0.47 rad (27°) idlers, bottom stands located on 3.05-m (10-ft) centers, top stands on 1.5-m (5-ft) centers, and is supported on a 19-mm (3/4-in.) diam

Jan 1, 1982

By Z. Henderson, J. Saylor, L. R. Mendoza

"Diesel particulate Matter (DPM) is a byproduct of fuel combustion in diesel engines. It is classified as a carcinogen, with associated respiratory and cardiovascular health effects. The composition, size, and concentration of DPM is dependent on factors such as engine type, loading and fuel composition. Though a number of DPM abatement and control strategies currently exist, particularly in underground mining environments, occupational exposures remain a serious health concern. As a novel abatement approach, DPM scavenging by fine water or “fog” droplets has been proposed and a laboratory set-up has been built to test the efficacy on engine exhaust. Here, we describe a series of tests that varied engine load, system flow rate and fog drop number density. While none of these factors had overwhelming effects on the results within the ranges tested, the improvement in DPM mass removal attributed to the fog treatment was about 45% on average in comparison to no treatment. INTRODUCTION Diesel engines have seen widespread use for well over a century due to their relatively high thermal efficiency and fuel economy1. More recently, however, adverse health risks of diesel exhaust have become increasingly clear. Many of these risks are associated with the physical and chemical properties of exhaust components1–3. The term diesel particulate matter (DPM) is used to refer to the solid components of diesel exhaust, which are a mixture of elemental and organic carbon (EC and OC) and minor constituents including sulfates and metal ash3. The OC fraction of DPM results from unburned fuel and lube oil, whereas EC or soot is formed during the combustion of locally rich regions within the fuel. DPM is classified as a carcinogen6,7 and epidemiological studies have demonstrated a positive correlation between long-term exposure to DPM and other combustion-related fine particulate and increased cardiovascular and pulmonary diseases8,9. Diesel engines operate in relative fuel rich/oxygen lean conditions and are characterized by relatively high emissions of particulate as compared to spark-ignition engines2,3,10. Typically, these emissions range from 107 – 109 particles/cc and cover two primary size ranges: the nuclei mode where particles have diameters less than about <50 nm, and the accumulation mode where diameters are from about 50-10,000 nm. Most OC resides in the nuclei mode as semi-volatile compounds, while most EC is in the accumulation mode3. The physical and chemical properties of DPM vary with the type of engine, fuel (e.g., petro- vs. bio-diesel) and operating conditions such as loading (i.e., a function of torque and rotational speed)2,3,9,11,12. Loading is a particularly important factor with respect to DPM toxicity9,13,14, and on the effectiveness of after-treatment technologies2,3,15. Engine load alone can affect the EC/OC ratio, and the size distribution and number density of DPM. For diesel engines, the load is roughly proportional to the equivalence ratio3, defined as the actual fuel/air ratio over the stoichiometric fuel/air ratio for complete combustion. Light loads generally favor the formation of OC and small particles. As load is increased the volatiles are oxidized leading to larger soot particles (i.e., EC), but lower total number density of DPM. With further loading, the formation of soot offsets the decrease in volatiles, resulting in increased DPM mean size and number density3."

Jan 1, 2017

By Z. Hyder

Simulation and modeling is powerful tool to analyze real time data and can be used to analyze different scenarios using appropriate software that may reduce need of infield data collection process and can predict reasonably accurate results. In this paper the real time data of a mine is used to simulate and model the stresses on the pillars and evaluate the pillar strength and safety factor. The material properties assigned to the model are obtained by testing the representative samples taken from the selected locations of the mine. The mine under investigation has 50 ft wide pillars and 50 ft wide rooms under an average overburden of 650 feet. The effect of reduced pillar dimensions and increased roof span on overall stability of mine and extraction ratio is analyzed using LaModel [1] software. The predicted results of the reducing pillar size are analyzed to compares the current mining practices with the optimized room and pillar size to get better extraction ratio without comprising the safety.

Jan 1, 2011

By F. Rudloff, C. Karageorgos, J. Moyo, I. Boadi, M. Struble, B. Lumsden

Over it’s more than 100-year history, the Kennecott operation has often been at the forefront of innovation; driven by the demands of the lower grade ore-body and the higher costs of operating in the US where wages are generally higher and regulation more restrictive. One way of reducing operating costs in c/lb is to increase the lbs produced at minimal cost. Despite the relatively coarse grind at Kennecott - about 30% >150μm, approximately 20% of the Cu lost to tail is liberated chalcopyrite in the <20μm fraction, and about 30%-40% in the <37μm fraction. In 2020 Kennecott undertook a detailed plant scale test of the magnetic aggregation technology to increase copper recovery by reducing fine copper losses. A paired statistical plant test of magnetic conditioning on one rougher line showed a 1.12% increase in Cu recovery to 97% statistical confidence. The next challenge, unforeseen at the start of the project, was the fabrication and transportation to site of the equipment for the three remaining rougher rows, during the severe supply-chain constraints of the Covid pandemic in 2021. This resulted in delays and unforeseen costs as world-wide transportation became chaotic, particularly transportation via west coast USA. Nevertheless, the project was completed and commissioned, with only minor delays and cost increases, due to a flexible approach to overcoming the hurdles encountered.

Feb 1, 2023

By C. Webb, M. A. Tuck

This paper describes the application of a cable disc elevator to continuous lift ore vertically from underground mines. Application of this system requires the tensions developed within the cable must remain within the carrying capacity of the cable including applicable safety margins. A critical element occurs at starting the system when it is fully loaded which requires the force developed by the system to exceed the static friction forces. This paper describes the laboratory rig developed to investigate the static friction forces. Details of the results of tests on three different ores for both dry and wet conditions are given. These results are discussed.

Nov 19, 2020