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By Douglas A. Sloan

Who would believe that young elementary school children could understand something as complex as the mining industry? THE CHALLENGE The challenge of accomplishing this is tremendous. An examination of Canadian school children indicated that they knew very little about the world of work in general, and hardly anything about the mineral resource industry in particular. It calls to mind the story about two youngsters who decided to play house. The little girl played her role well as she went about the house doing things she had watched her mother do every day. When it was the little boy's turn, he grabbed his lunch, waved goodbye to his "wife", jumped on his bicycle and pedalled furiously down to the end of the driveway -- where he stopped. The youngster explained that he saw his dad go out of the driveway each morning, but he didn't know where he went, or what he did on the job. When you stop to consider the number of families today with two working parents, you can begin to appreciate the importance of the opportunities for role identity provided by this project.

Jan 1, 1979

By J. Dorsey

In 1910, Colonel Boyce Thompson, who owned Inspiration (now Cyprus Miami) and various other mining interests, formed the Magma Copper Company and leased the Silver Queen claims around Superior, Arizona. At the same time, he purchased other claims around the Silver Queen claims from what was then called the Magma Mine. The mine continued to operate until 1982 when Newmont Mining Company, who owned Magma Copper Company, shut down the operations due to high costs and low copper prices. When Magma was spun off by Newmont as an independent company in 1987, new studies of Superior were started. It was clear from these studies that the mine had been shutdown and over 1400 employees laid off for two basic reasons: first, as a resu1t of a mine plan that was technically flawed and second, be-cause of very high production costs mainly due to the low productivity from a very high cost work force. During 1989 a plan was formulated to re-open Superior with the determination to over-come the problems that resulted in closure. A new mine plan was developed and a management style developed that promotes team work and high productivity.

Jan 1, 1992

By Richard Giffen, Martha Gross, Luca Pellegrini, Pa Ousman Njie

The Hampton Roads Bridge-Tunnel (HRBT) Expansion project in Virginia includes parallel 1.5- mile (2.4 km) tunnels constructed using a tunnel boring machine (TBM). The TBM launching and receiving shafts were excavated within the footprint of two reclaimed islands abutting the navigation channel for the Port of Virginia. The shaft excavations—a circular tri-cell shaft at South Island, and a circular-rectangular twin-cell shaft at North Island—were supported by slurry walls up to 190 feet (58 meters) below the island surfaces. This paper describes specic design considerations for these shafts, as well as construction and uality-oversight aspects of their excavation and construction.

Jun 23, 2024

By W. Rocher

The Minera Ojos Del Salado (?MINOSAL?) concentrator is located 20 kilometers southeast of Copiapo, Chile and processes copper ore provided by its Santos and Resguardo mines at a capacity of 4,200 tip (4,620 stpd). Phelps Dodge acquired the majority interest in MINOSAL in 1982. The principal incentive for this purchase was the exploration potential of the property. At that time, the concentrator plant was a small, antiquated installation with a capacity of 674 t/d (740 stpd). In 1982, the majority of the ore was produced from the Santos and Resguardo mines, but custom ores of copper, silver, and gold were also treated. The acquisition occurred at a crucial time in the copper business, since the price had fallen to nearly $0.50 per pound. In 1985, Phelps Dodge purchased the outstanding interest in MINOSAL and acquired 100% of the property. Today, after numerous improvements and two expansion projects, the concentrator is an interesting combination of old and new equipment. The regrind mills, for example, have been in service for about 50 years, while the ceramic concentrate filter represents the latest technology.

Jan 1, 1993

By Martha Gross, Amanda Wachenfeld, Brian Keaney, Jean-Michel Charpentier, Frank Perrone

The Hampton Roads Bridge-Tunnel (HRBT) Expansion widens the existing four-lane bridgetunnel corridor to eight lanes through construction of two parallel tunnels, interstate widening, and bridge expansions. As part of the design-build contract, a supplemental geotechnical investigation was completed to support the design. The investigation for the subaqueous tunnel segment consisted of over 48,400 linear feet of drilling and 7,100 laboratory tests. This paper discusses the challenges of planning and executing a large-scale geotechnical investigation for underground works in a marine environment and the use of big data for effectively managing, interpreting, and transmitting data to the design-builder consistently throughout the investigation.

Jun 23, 2024

By A. G. Mayton, D. H. Ambrose, C. C. Jobes, N. K. Kittusamy

In a systematic study, the National Institute for Occupational Safety and Health (NIOSH) evaluated seat designs in low- and mid-seam shuttle cars during production operations at two underground coal mines in southern West Virginia. The purpose was to support, with additional data, earlier findings that NIOSH ergonomic seat designs (featuring viscoelastic foam padding and lower-back support) may help reduce health risks to operators of coal mine shuttle cars. Eight shuttle car operators evaluated seven seat designs (one already in use in each vehicle and five NIOSH designs) relative to perceived and measured whole-body vibration (WBV) exposure (including vehicle jarring/jolting) and discomfort. Operators’ perceptions using a visual analog scale (VAS) and questionnaire ratings were compared with International Standards Organization (ISO) 2631-1:1985 fatigue-decreased proficiency (FDP) limits and measured WBV levels on low- and mid-seam shuttle cars. Objective and subjective data results indicated that NIOSH seat designs (with added adjustability, lower-back support and improved seat padding) performed better to reduce vehicle jarring/jolting levels and that shuttle car operators favored them over existing seat designs. The NIOSH low- and mid-seam shuttle car seats showed 45 to 77 percent better performance in FDP and 9 to 60 percent better performance overall in operators’ ratings. Considering the VAS results for low- and mid-seam shuttle cars under no-load conditions, operators rated the level of jarring/jolting 18 to 89 percent lower with the NIOSH seats. Reductions in measured vehicle jarring/jolting were 19 to 46 percent for the three-directional vector sum accelerations relative to the existing seats on the low- and mid-seam shuttle cars. Questionnaire responses indicated that operators for both shuttle car models rated NIOSH seat designs as more comfortable overall. Vehicle operators most frequently suggested adding armrests to improve the seats on the mid-seam shuttle car. A suggested improvement for the low-seam shuttle car was to make the seat a better fit for the operator compartment, which would enhance clearance between the operator and vehicle controls and allow for better seat adjustment and operator visibility.

Jan 1, 2009

By James S. Hanson

Existing models proposed for the bacterial leaching of metal sulfides generally fail to predict solubilization rates at times greater than a few tens of hours. The reasons for this may be that these models are empirically based and use first order bacterial and chemical oxidation rates. This type of model is satisfactory for short time predictions (on the order of 20 hours) when the bacterially catalyzed dissolution is relatively minor. However, when bacterial action becomes more pronounced, these models consistently predict higher dissolution rates than those commonly observed in laboratory experiments. The present model uses several fundamental chemically and biologically based assumptions to predict the dissolution rate of a chalcopyrite concentrate for extended leach times up to the precipitation of jarosite. The main assumptions made are that Monod growth kinetics prevail, T. ferrooxidans adsorb onto the surface of the mineral (not necessarily mineral specific), and that during periods of high growth oxygen transport may become rate limiting. The model also relies on the energy efficiency of the bacteria in fixing carbon (growth yield) and correlates this value with available surface area of the mineral particles and the bacterial growth rate.

Jan 1, 1989

By R. Gerling

A computer program has been developed for finding a near-optimum schedule of the mining sequence for flat lying, tabular orebodies. The deposit is divided in blocks with equal areas and definite grades, thicknesses and ore contents. Mining is done by room and pillar method and trackless haulage to surface. Access from surface is by adits or ramps with additional vent raises. In total eight different general concepts for access and development can be realized. The optimum mining sequence is found by a heuristic method. Criterion is the maximization of the net present value over the lifetime of the mine. Specific stoping costs per t of ore are taken for con¬stant, whereas development and haulage costs for individual blocks and also sequences will be different. Correct ventilation and a technically sensible sequence are guaranteed. Beginning with a single block, neighbouring blocks are tested and an optimum stoping sequence is generated. The net present value of the total mining operation for the planning period is calculated, taking into account ore, which is mined during development. The program can also be used to investigate given mining sequences.

Jan 1, 1986

By Emily Adelsohn, Robert Winn, Anthony Iannacchione

"Over 600 longwall panels have been mined in Pennsylvania in the last 50 years. Of those 600 panels, 25 panels undermined interstate highways. Despite this quantity of panels, much is still unknown regarding the detailed effects of undermining highways. The Gateway Mine, the Emerald Mine, and the Cumberland Mine undermined I-79 with 17 panels between 1982–1989 and 2003–2008, respectively; mine Eighty-Four undermined I-70 with 4 panels between 1987–2000.Through the examination of the panels that undermined I-70 and I-79, it is possible to determine which factors have most impacted the highway alignments. In some locations, the highway intersects with panels at angles ranging from 45 to 80 degrees, and at others, it runs between two panels, which simulates the effect of gateroads on the subsidence. The panels width to overburden ratio varies between 0.64 and 1.7, meaning that the interstates were influenced by both subcritical and supercritical subsidence basins. The face advance rates and overburden depths also vary between the panels.Unfortunately, specific information detailing highway impacts associated with unique characteristics of the subsidence basins are limited. However, using the profile function model and influence function model within the Surface Deformation Prediction System (SDPS), the effects of overburden, panel size, and orientation of the road to highway can be indirectly assessed by profile and influence models of subsidence basin formation.INTRODUCTIONCoal mining has been an integral part of Pennsylvania’s history. Room-and-pillar mines have been active since the late-1700s when coal was extracted from outcrops. By 1830, the city of Pittsburgh alone consumed more than 400 tons of bituminous coal each day for domestic and industrial use (PADEP, 2019). In the late 1960s, the face of mining in Pennsylvania changed with the development of full extraction longwall mines. Since that development, over 600 longwall panels have been mined in the Pittsburgh Coalbed in Pennsylvania alone (PADEP, 2019).As longwall mining and other forms of full extraction mining have increased in popularity, the amount of planned subsidence impacting the surface has also increased. The stresses and strains induced by longwall subsidence can cause damage to the surface as well any structures, water supplies, or water bodies that lie above the panel. Since the behavior of soils and structures vary, one way to study the surface effects of longwall mining is to analyze the impact on flat, rigid, pavement surfaces. Examining factors that vary the impact of subsidence with respect to highway alignment can demonstrate the favorable orientation of an alignment to avoid or mitigate damage and critical impact zones in a subsidence basin."

Jan 1, 2019

By Nicholas Tabor, Norbert Fuegenschuh, Richard Taylor, Jean-Marc Wehrli

The Plymouth Tunnel forms part of the 16-mile long route of the Purple Line Light Rail Project promoted by the Maryland Transit Administration. The tunnel is approximately 1,220 feet in length with a shallow vertical alignment located beneath a residential area. Challenging mixed ground conditions included surficial soils, decomposed Saprolite, and highly weathered to fresh rock requiring the use of the Sequential Excavation Method (SEM) for construction. This paper discusses innovative approaches implemented during construction as well as challenges faced during planning and installation of a spray-applied permanent concrete liner.

Jun 13, 2021

By Randy Ynchausti

ERIC GUTIERREZ, Knowledgescape: Our next speaker is Randy Ynchausti. He's the director of development, Knowledgescape systems division, of EIMCO Process Equip- ment Company. The title of Randy's talk is "An Expert Control System for Phosphate Beneficiation." RANDY YNCHAUSTI: System integration. How does the systems integrator survive when caught between plant engineers, plant management, and third-party engineering firms, and stay within the budget of the corporate goals? I'm not sure that anyone knows how to do all of that on one project. Results are critical when we talk about how systems integrators work with operating people, how the operating people want systems integrators to work with them, and how both groups work together so that at the end of a project, you have been provided with solutions that meet your needs and solve your problems at a fair price. How does the integrator's role change when working with different types of professionals, such as plant managers, plant engineers, engineering firms, or other system integrators? Finally, what is the dynamics of people working with machines and providing services and solving needs? The average number of employees per pound of copper processed has decreased significantly during the past 15 years. I would dare to generalize and say that the average number of employees per whatever unit of measure we have in whatever industry we work in has decreased over the last 15 years. From a system integrator's perspective, there are some clients who lack a bit of internal expertise as corporate downsizing occurs, and that's one reason why we go out to system integrators or third-party vendors and buy things from them to solve our problems. Downsizing really amounts to savings, but more than that, I think Brian expressed this and I agree with him, it also amounts to a cost. Unfortunately, most of us count the savings and none of us count the cost in that approach. It's easy to count the savings, which is one reason why we count it so quickly. Maybe that also accounts for why we set our pencils down so quickly after we get that dollar value. Maybe we should pick that pencil up every once in awhile and refigure the expense, the cost to us, and determine what we're going to pay during the next year or two or three in losing that expense, or that staff. A broad experience base accumulated over projects at various plants helps system integrators to provide services to clients. This experience enables the system integrator to

Jan 1, 1998

By William Gleason

Despite a global slowdown in most mining sectors, Caterpillar, the world?s largest mining equipment maker continues to forge ahead with new, and improved offerings to the global mining industry. On Nov. 10, as part of its Loading and Hauling Mining Focus Session at its Tinaja Hills proving grounds south of Tucson, AZ, Caterpillar unveiled to customers and media its two latest mining products, the 994K wheel loader and 6020B hydraulic shovel. The Caterpillar 994K wheel loader builds on a nearly 25-year history of the 994 model but with one noticeable difference ? the 994K is bigger ? much bigger. Weighing in at 239,142 kg (527,218 lb) the 994 K is up to 20 percent larger and comes with up to 30 percent increase in payload capacity. This behemoth of a machine is currently being tested at Caterpillar?s Tucson Proving Grounds, Anglo Gold Ashanti?s Cripple Creek and Victor gold mine in Colorado and Taseko?s Gibraltor copper and molybdenum mine in British Columbia, Canada.

By L. Yan, B. Lambie, J. Srednicki, J. Carr

Electromagnetic emissions from electrical devices may interfere with electronic safety systems or other devices in the mining environment. This electromagnetic interference (EMI) may cause unwanted changes in the performance of the affected devices and may cause safety issues for miners. To minimize the risk of EMI, the National Institute for Occupational Safety and Health (NIOSH) has conducted research quantifying the electromagnetic emissions of several types of equipment that might be used in the mining environment. Previous research has shown that welding arcs can give off ultraviolet (UV) emissions, visible light, and infrared (IR) emissions that can cause health problem on skin and eyes. In this study, the electromagnetic emissions of the shielded metal arc welding (SMAW) process were monitored and measured. Several factors including operating mode (AC, DC positive or DC+, DC negative or DC-), current setting (low, medium, high, maximum), and electrode type were investigated to compare their effect on emission level. The test shows that the emission level from the welding process can be affected by those factors. The test data also shows that, among those factors, the operating mode has more influence on emission level than do current setting and electrode type. The information in this paper can be useful for the mining industry to better understand the emission in the 9-kHz to 500-MHz frequency range from a SMAW welder.

Feb 1, 2023

By Robert W. Curtis

Kaiser Aluminum & Chemical Corporation's (KACC) entrance into the alumina market began in 1946 with the purchase of a small plant in Baton Rouge. Louisiana. Since that time KACC has been involved with the design, construct; on, and operation of many alumina plants around the world. One of these plants is located in Gramercy, Louisiana. The Gramercy Works is a multiplant installation consisting of an alumina plant, a caustic-chlorine plant, a petroleum coke calciner and a fluorochemicals plant. Each of these plants require their own specific environmental control programs to abate pollution. Kaiser has made significant progress through the years on their own initiative in pollution control. But many new challenges have been and continue to be created with the enactment of environmental laws. The 1970 Clean Air Act Amendments, the resurrection of the old "Refuse Act" in 1970 and finally the 1972 Federal Water Pollution Control Act Amendments prompted the formulation of our current philosophy towards the abatement of pollution. Since the formulation of these complicated pieces of legislation, others equally complicated, have come to being. The Federal Insecticide, Fungicide and Rodenticide Act as amended by the Federal Environmental Pesticide Control Act of October, 1972, the Toxic Substances Control Act of 1976, the Solid Waste Disposal and Resource Recovery Act of 1976 and the Safe Drinking Water Act sighed in December of 1974 have all contributed to the challenge for an alumina plant to meet regulatory constraints. However, this paper will only discuss the alumina plant?s environmental programs designed to meet compliance with air and water pollution legislation. At the Gramercy Alumina Plant, over $25 million has been spent for pollution control since 1969. The Gramercy Plant is a prime example of KACC's commitment to meeting the environmental challenge.

Jan 1, 1978

By Y. Pan, V. V. S. Vytla, P. Tukkaraja, R. BHARGAVA, S. Jayaraman Sridharan

Panel caving is an underground bulk mining method that utilizes gravitational force for mining massive, steeply dipping, and deep-seated ore deposits at a lower operating cost. To control dust and gas emissions entering the production level during the extraction of ore from the draw points in a panel cave, relatively negative pressure is created in the cave by installing an exhaust fan in the exhaust drift located on top of the cave. Since caving is a dynamic process, the design of an effective ventilation system is a challenging task, and therefore, estimation of airflow resistance offered by the broken rock inside the cave is critical. The complex and dynamic nature of caving also makes it difficult to predict the airflow resistance by using traditional approaches. This study investigates the effect of changes in the bulk porosity of the broken rock on the cave airflow resistance using computational fluid dynamics (CFD) approach. The results show an inverse relationship between the cave airflow resistance and the bulk cave porosity. The pressure-quantity characteristic curves presented in this paper provide valuable information for sizing and operating an exhaust fan used for a mature panel cave ventilation.

May 17, 2022

By Tyler Lahti, Peter Borgacci, Mary Jane Ferraro, Prakash Nadesparan

Toronto Tunnel Partners (TTP), under contract to Metrolinx/IO, is constructing new twin rail tunnels under the Highway 401 & 409 interchange to accommodate additional tracks to support the GO Expansion program for future two-way, all-day service. The new tunnels are being constructed using the Sequential Excavation Method (SEM) and utilize a tunnel pre-support system consisting of a series of 800 mm diameter steel pipes to form a pipe canopy. The pre-support pipes were installed with an Auger Boring Machine (ABM) in four separate headings; one heading from each of the tunnel end portals, and two from a shaft in the middle of the highway. To facilitate the auger boring operation, a custom steel reaction frame was required to counteract the thrust from the ABM at the portals, and a temporary shaft structure was installed in a narrow median space of the highway. The installation of the pipe canopy had to overcome challenges including removal of obstructions, alignment issues, and controlling settlements to the highway surface. This paper discusses the purpose of the pipe canopy, design and installation of the temporary shaft and structures to support the auger boring operation, the experience of the contractor during the installation of the pipes, and brief overview of the experience tunneling below the pipes.

Jun 13, 2021

By Ruichen Ren, Xu Han, Caixia Li, Zengchuan Yue

In this paper, the size-density distribution of coarse middling coking coal (CMCC) with different grinding fineness and flotation concentrates was investigated. Then, the flotation behaviors and liberation characteristics of different size-density fractions in ground CMCC were analyzed, and the different size-density fractions were divided into five categories: mostbeneficial, secondary-beneficial, poorly liberated, insignificant-pollution, and serious-pollution. Based on the content of particles with different liberation characteristics, an evaluation index of the liberation characteristic of ground CMCC, namely, the liberation perfection index (LPI), was proposed. The results indicated that grinding changed the size-density composition of CMCC, which affected the flotation performance. Insufficient grinding and overgrinding were not beneficial to flotation. Insufficient grinding caused a higher content of poorly liberated particles and a lower content of most-beneficial particles. Overgrinding increased the content of serious-pollution particles and reduced the content of most-beneficial particles. The size order of the LPI values of different ground CMCC was consistent with the flotation efficiency, and the LPI values of the other two similar samples were overall positively correlated with their flotation performance, suggesting that the method is universal.

Feb 14, 2023

By Richard Campbell, Claire Pirona, MEHMET KIZIL, Ismet Canbulat, Stephen Giese, Ravindu Goonawardene, Edward Steed, Serkan Saydam

The Australian longwall mining industry spends millions of dollars per year on proactive and reactive ground consolidation applications across most of the operations currently in production. The design and effectiveness of the applications and products vary widely and are based predominantly on-site precedence or what were considered successful applications at other sites in similar situations. In the continual improve the effectiveness of how consolidation products are used and when by enhancing our knowledge of the mechanical properties of products used in underground coal applications and applying this increased understanding to geotechnical design. One of the current challenges to further developing more appropriate and accurate geotechnical design methods for consolidation activities is the lack of standardised materials testing and knowledge of rock mechanics data on in situ performance. The lack of industry standardisadesign of consolidation programs, with a reliance on experience-based guidance for rockmass consolidation design. consolidation products. The program was designed to provide the industry with a set of geomechanical property index tests and a data set that can be utilised by rock mechanics engineers as baseline information for product evaluation and engineering design. The laboratory work undertaken is critical to understanding the exact small-scale mechanical properties of these products and testing was carried out at Monash University for various states of curing of each product. Recognising that the speed at which a mixed product develops its desired properties to act as a support element in underground coal mines is critical to its serviceability. This paper presents the testing rationale proposed, the testing results, and a framework for how the data set can be used to improve the engineering basis for ground consolidation design, in terms of expected rockmass performance under various mining conditions and application parameters.

Jun 25, 2024

By Dean Brox

Tunnel boring machines (TBMs) have been used for the construction of various tunnels for mining projects for the purpose of access, conveyance of ore and waste, drainage, exploration, water supply and water diversion. Several mining projects have seen the successful and economic beneficial use of TBMs, and there is an increasing awareness of the benefits of TBMs for mining projects. Key technical considerations for the use of TBMs for the construction of tunnels for mining projects include geological issues (rock type, rock alteration, rock strength, rock abrasivity, durability, ground water in flows), depth of cover and the potential for overstressing/rockbursts, site access and terrain, portal locations, TBM constraints, minimum tunnel size, tunnel support requirements, contractor and labor experience, and project schedule demands. TBMs offer key project schedule benefits with high rates of progress, which is a unique economic advantage recognized for mining projects where timing is of the essence in order to advance mining development and achieve early startup for operations. A thorough evaluation of the anticipated ground conditions should be performed as part of the decision to adopt a TBM for a mining project. Minimum specifications for TBMs are necessary in order to prevent the incorrect type of TBM from being used. Appropriate geotechnical investigations are necessary in order to provide key information on the anticipated subsurface conditions for careful planning and design of the proposed tunnel alignment. The overall site and geological conditions associated with some projects may suggest that it is not appropriate to use TBMs for some mining projects due to a perceived higher risk. Key words: TBM, Tunnel boring machines, Tunneling in mining

Feb 1, 2014

By Dean Brox

Tunnel boring machines (TBMs) have been used for the construction of various tunnels for mining projects for the purpose of access, conveyance of ore and waste, drainage, exploration, water supply and water diversion. Several mining projects have seen the successful and economic beneficial use of TBMs, and there is an increasing awareness of the benefits of TBMs for mining projects. Key technical considerations for the use of TBMs for the construction of tunnels for mining projects include geological issues (rock type, rock alteration, rock strength, rock abrasivity, durability, ground water inflows), depth of cover and the potential for overstressing/rockbursts, site access and terrain, portal locations, TBM constraints, minimum tunnel size, tunnel support requirements, contractor and labor experience, and project schedule demands. TBMs offer key project schedule benefits with high rates of progress, which is a unique economic advantage recognized for mining projects where timing is of the essence in order to advance mining development and achieve early startup for operations. A thorough evaluation of the anticipated ground conditions should be performed as part of the decision to adopt a TBM for a mining project. Minimum specifications for TBMs are necessary in order to prevent the incorrect type of TBM from being used. Appropriate geotechnical investigations are necessary in order to provide key information on the anticipated subsurface conditions for careful planning and design of the proposed tunnel alignment. The overall site and geological conditions associated with some projects may suggest that it is not appropriate to use TBMs for some mining projects due to a perceived higher risk.

Jan 1, 2013