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By P. M. Soupios

An integrated suite of environmental methods was used to characterize the hydrogeological, geological and tectonic regimes of the study area, to determine the geometry of the landfill (depth and spatial extent of electrically conductive anomalies), to define the anisotropy caused by bedrock fabric fractures and to locate potential zones of electrically conductive contamination. The study area which covers an area of about 0.08 Km2 is a municipal solid waste site (MSW), located 20Km West of Herakleion in the central part of Crete (S. Greece). The landfill is located in a northwest oriented valley with highlands to the northeast and southwest. The combination of geophysical methods and chemical analysis are commonly implemented for characterization and management of land-fills. At the particular site, geophysical methods were focused on studying the electrical insolating properties of the materials, electrical con-ducting properties of fluids (leachates) and electromagnetic properties of the disturbed regolith materials in the burial zones. Three different types of geophysical surveys were performed: 1) 2D electrical tomography (ERT), 2) electro-magnetic measurements using very low frequencies (VLF) and 3) electromagnetic conductivity (EM31). Furthermore, in order to calibrate the geophysical methods dielectric spectrometry measurements are conducted. To evaluate the environmental degradation of the area, soil and liquids samples were collected.

Jan 1, 2005

By José Ricardo Lopes, Alaor Coelho, Marco Gomes, Alfredo Dacio Moraes Filho, Akira Koshima

"Very low strength alluvial peat soil was found under two old drainage galleries with just 4.3m cover above a twin tunnel due to be excavated by a 10.6m diameter EPB Shield for São Paulo Metro’s Line 5. Alignment was required to strengthen soil and drive the TBM through safely without damaging the galleries. The design included six levels of self-drilling forepoling with lengths up to 15m, using 100 mm-diameter SCH160 metal tubing and injection bulbs with estimated 0.20m diameter. Two 6m-diameter circular shafts were excavated along the shield-tunnel axis, one each side of the galleries, and forepoling fanned out under gallery foundations. Given the peculiar soil and confined working space, more data were needed for correct drilling geometry. Ground mass treatment was successfully designed and executed and galleries were fitted with instruments to enable the shield’s advance. DESCRIPTION São Paulo Metro’s Line 5 (aka Lilas or purple line) is adding 11 stations along an 11.5km extension and three EPB TBMs are being used simultaneously (three EPBs on the same job for the first time in Brazil) with one of them excavating a large cross- section twin-track tunnel. Currently the largest work-in-progress for São Paulo Metro, this project has been divided into seven lots and 9km are already operational. This study refers to Lot 6 where the 10.6m - diameter EPB shield excavation is only 4.3m below two galleries running through a 10m layer of very soft peat soil in an old alluvial riverside region ringed by major roads. After recent filling, this area (Parque das Bicicletas) was used for recreation, although temporarily it has become a construction site. This paper will describe the original basic design; precautions in relation to the structural condition of the galleries after inspection; the problem of absence of data for their foundations; subsoil bore tests; evolution of the engineering design for the galleries and conditioning and reinforcing the soft soil below the galleries to ensure safe advance of the EPB shield, and finally the successful outcome of the solution used."

Jan 1, 2016

The purpose of this talk is to report the answers to the-'two following questions: I. What unique services does the mining industry expect of mining and mineral processing engineers? II. What suggestions does industry offer to educators to help revamp curricula to meet the needs of a changing industry? As the result of many questionnaires filled out in person by presidents, managers, superintendents, chief engineers, metallurgists, and other responsible individuals in operations and management of large and small metal and nonmetallic mining companies in the U. S., and to some extent abroad, we now have some, specific answers to the above questions. Although answers to questionnaires continue to arrive at this writing (February 10) the volume already received is sufficient to clearly justify certain conclusions and observations. A copy of the tally of the first 117 questionnaires received accompanies this report, and I am certain that a compilation of additional questionnaire data will merely reinforce, the trends in thinking that have been' established thus far. Here are the results of the survey:

Jan 1, 1961

By J. S. Spivey

We in the coal industry, especially in the State of Illinois, put tremendous emphasis, including time, money and effort, into on-the-job training. The results of such training and safety have been tremendous. For example, in 1981 Illinois was the first major coal producing state in the history of coal mining to have zero mine-related fatalities. And in 1985, I am very proud to say, we had the second best record in the history of coal mining, with only two fatalities. Obviously, one fatality is one too many. Our goal is, has been and will continue to be to strive for excellence. It is sad, however, that in 1981 while were were celebrating zero fatalities in the workplace, there were 21 fatalities that occurred off the job. Thus, it has become a classic American story. Success with safety has been found in the workplace, but training and preparation to prevent accidents away from the job site have almost been ignored. Accidents are the leading causes of death in the United States for all persons age 1 thru 38, and are the fourth leading cause of death for people of all ages. Every single day, on the average, more than 290 Americans are killed in accidents - a rate of one every five minutes. The leading cause of fatal accidents in the U.S. is motor vehicles. And the number two cause is home accidents. A staggering statistic is that people are being killed off the job at a rate of about 9 to 1 over those on the job.

Jan 1, 1986

By Verya Nasri, Jaeseoung Lee, Ashish Bhargava, Shashank Gupta

This paper presents the unique design and construction challenges for the Technoparc Station, located in downtown Montreal as a part of Réseau Express Métropolitain (REM), a light rail rapid transit system. The station is located 15 m below the street with rock-bearing secant pile wall as the primary structural system working as both the retaining and gravity structure. The paper highlights the challenges related to the support of excavation structure, invert slab resisting high hydrostatic forces, waterproofing tightness etc. It also focuses on the importance of Building Information Modeling (BIM) in underground tunneling projects for effective coordination, clash-free, optimized design and costs.

Jun 13, 2021

By Robert D. Coale

This paper will describe the copper concentrate slurry pipeline and pumping system between the concentrator and the port at Bougainville Copper Ltd. The operations of Bougainville Copper Ltd. are located on the island of Bougainville in the South Pacific. Geographically, it is the northernmost island of the Solomon Group but, politically, it is part of Papua New Guinea. Papua New Guinea is a United Nations Trust territory administered by Australia, having recently been given self-government, with independence scheduled for December 1974. (Fig. 1). The island is approximately 130 miles long by 30 miles wide, with the Crown Prince mountain range forming a spine along its length. The mountains in place are over 8,000 feet high with the mine located on the western flank at an elevation of 2,200 feet. Exploration on Bougainville for copper by Conzinc Riotinto of Australia (CRA) began in 1963 and by 1968, through geophysical, geochemical and diamond drilling methods, an orebody containing nearly one billion tons of ore grading approximately 0.48% Cu. and sane gold had been outlined. Bougainville Copper Ltd., the company operating the mine, is 53.6% wined by CRA, 20% mined by the government of Papua New Guinea with the public Folding the remainder of the shares. The first copper concentrate was produced in early 1972, with production for the first full year, 1973 being:

Jan 1, 1974

By D. T. McMurray

INTRODUCTION Shabanie mine, situated some 180 km east of Bula¬wayo, has been a producer of chrysotile asbestos for more than 50 years. The ore bodies occur in serpentinized dunite, which overlies talc-carbonate schist. A zone of relatively competent rock of varying thickness occurs between the schist and the ore bodies, which are gen¬erally less competent. The hanging wall of the ore bodies is economic, and the hanging-wall serpentine carries a variable subeconomic amount of fiber. It is important to note that, in general, the ore body competence is less than that of the foot and hanging-wall formations. Historical After surface operations ceased, cut-and-fill stoping was used to win ore from underground; this was success¬ful until the increasingly stoped-out area caused insta¬bility in the stope pillars and back. Consequently, dur¬ing the early 1950s, a gradual change to cave-mining methods was made, the ore being won by hand lashing in drawpoints, situated in the basement of the stope blocks, and passed through orepasses under gravity to the haulage level some 13 m below. About this time, interest was focused on the sub¬level caving method in use in Swedish iron ore mines: it was felt that it might be applied economically to the Shabanie ore bodies. Accordingly, in 1958, an experi¬mental stope block was laid out in which sublevel inter¬vals and extraction tunnel spacing were 9 m. The tun¬nels (ring drilling drives) were oriented on strike-in contrast to the Swedish system, in which crosscuts that retreat from hanging to footwall are used. The advantages of the method were quickly appre¬ciated by the operating personnel and, despite the in¬evitable teething troubles pertaining to the introduction of any new mining method, it was not long before sub¬level caving was providing a high proportion of the mill feed. The disadvantages also became apparent at an early stage, however, and, from that time to the present, continuing modifications have been made to mining lay¬outs in an effort to improve ore recovery. GENERAL DESCRIPTION OF METHOD The mine is served by a vertical hoisting shaft, in which two skips, a man cage and a service cage, provide adequate capacity for production requirements. The rock hoist is a Ward Leonard control hoist, in which two electric motors drive a common gearbox. The man winder is driven by an a-c motor. Several auxiliary shafts provide secondary egress and intake and return ventilation. Main haulage levels are above (Fig. I a and b). Blasthole fan patterns are drilled by drifters of 100 mm bore, drilling 41-mm holes; when a sufficient strike length has been drilled, a slot is cut in the upper¬most sublevel and the rings are broken into the slot. Initially, a limited tonnage is drawn, since it is essential to ensure that the hanging wall caves behind the retreat¬ing stope face. Once this has been established, maxi¬mum tonnage can be drawn, as described later in this chapter, under the heading "Draw Control." The broken rock is loaded by 0.14 and 0.20-m3 load¬ers into cocopans (rocker-dumping type of tipping truck), which are hand trammed to orepasses, discharg¬ing on the haulage where 11-t electric trolley locomo¬tives haul 3.95-m3 Granby cars to the main shaft bins. As is evident from Fig. 1, the layout is simple, the block is brought rapidly into production, there is a high degree of selectivity and flexibility, and the result is a low-cost high-productivity mining method. DEVELOPMENT Main haulages are developed at 3.2 x 3.2 m, and once the service winze connections have been completed the development of the sublevels is undertaken. The footwall drives are cut first, to obtain access to the block. These ends are of the standard section, 2.4 x 2.8 m, and from them crosscuts at intervals of 70 m are driven through the ore body to the hanging wall. These crosscuts are used to supplement the geo¬logical information previously obtained from diamond core drilling, and they provide additional and more de¬tailed data on fiber percentages and lengths, structural features, and other relevant criteria which are used to build up the geological assessment of the area and to classify it in terms of the geomechanics rock classification (Laubscher and Taylor, 1977). The crosscuts also allow the necessary orepasses to be sited conveniently so that tramming distances from the loading points are not excessive. Development Drilling Once the skeleton development has been completed, the extraction headings are developed at 2.4 x 2.4 m as shown in Fig. 1. Standard development practice is to use crews of a machine operator and his helper, equipped with air-leg mounted jackhammers, to drill rounds of 1.8 m with integral tungsten carbide tipped drill steel. The round drilled is a normal drag round, as shown in Fig. 2, but considerable attention is paid to the drilling of the perimeter holes to use effectively the

Jan 1, 1982

By D. Gatzemeier

The Jewett mine is a surface mine in central Texas, producing about 8,000,000 tons/year of lignite. The mine covers 46,000 acres of land. Approximately 430 people are employed by Northwestern Resources Company and through their efforts, the Jewett Mine is one of the most productive mining operations in the country. The Jewett Mine utilizes a unique structure of staff to convert Operations Research into plans which can be implemented at the "front line" level of the Operations Team. This planning not only makes the mine cost effective and efficient, but promotes creativity in mining, which promotes ongoing research to lower the cost of mining.

Jan 1, 1993

By Olivier Martin

In busy and historic cities, traditional open box metro stations are becoming outrageously difficult, unacceptable for the citizen and uneconomical. Hybrid stations provide an interesting alternative. In-house experience of Gautrain (South Africa), West bay (Qatar), Cairo line 3A (Egypt), and Melbourne (Australia) all aim to reduce disturbance to the city and its inhabitants during construction. Constructed in rock or in deep soil under water table, they take advantages of the latest construction techniques from cement grouting to freezing, and from traditional excavation of cavern to large tunnels constructed by sophisticated tunnel boring machines (TBM). Today, they form the ultimate construction challenge.

Jun 13, 2021

By Thomas E. Shufflebarger

Definition of glass sand prospects may be modified by constraints which range from demography to critically important product-control. Characteristics of usable raw materials, physical and chemical, are discussed; an ideal raw material is defined. Following field investigations and preliminary sampling, evaluation of selected prospects includes use of modern drilling techniques, viz.: core, percussion (air-hammer), auger, jet, rotary jet, split-spoon and other. Nearly complete core (sample) return is mandatory. Land-use regulations, availability of water and transportation continue to direct exploration in a major sense. But fitting a prospect to burdensome politics nay be considered a decidedly negative factor.

Jan 1, 1983

By V. Carabias-Hütter, A. J. Basu

The paper aims at promoting sustainability assessment and reporting into practice using a globally acceptable set of guidelines and a common framework for internal and external reporting at a project/site level. Indicators are used for measuring performance, and this paper addresses development and implementation of performance indicators for sustainability assessment and reporting at local as well as global levels. The selection of a proper set of indicators is a challenging task. The indicators selected should provide the expected information for making right decisions. Relevant and credible sustainability reporting supported by a consistent performance indicator system can be the starting point for benchmarking environmental and social performance for the natural resources sector.

Jan 1, 2004

By G. K. Hoffman

Humate, defined as weathered coal or mud-stone rich in humic acid (HA) and fulvic acid (FA) have been mined, primarily as soil amendments or drilling mud additives, in New Mexico for 15-20 years. The New Mexico humate resource is estimated to be 11 Gt, including weathered coal and organic mudstone. The HA and FA content determines the end-use, therefore a simple and consistent method of measuring organic-acid content was developed. The New Mexico Bureau of Mines and Mineral Resources method is based on repeated alkali leaching and acid precipitation. Precipitates of humate are ashed, with mass balance of solids maintained, to correct for material added during alkali-acid treatment. Analyses of upper coal member, Cleary Coal Member (Menefee Formation) and Fruitland Formation samples from the southeast San Juan Basin show ashing to be important in accurate analysis of FA content. Ash in the total FA fraction averages 70% compared to 2% in HA. The FA in weathered coal and organic mudstone are similar, although HA is significantly higher in the former. As weathering progresses, the FA content of weathered coal increases faster than in organic mudstone because of the greater total organic material in coal.

Jan 1, 1994

By Claus Becker

At the RETC 1979 in Atlanta/Georgia it was reported about the beginnings of the Hydroshield system and the first site experiences. Since that time over 10 miles of tunnels in various diameters have been built with that system, and the discussion of the two most interesting projects will be the main topics of this paper. AURELIA TUNNEL, ROME In Rome, the railway system is going to be completed and modernized. Therefore, it is necessary to tunnel through the Roman hills. Part of the new railway system is the Aurelia Tunnel, located some 100 feet below the famous Via Aurelia Antigua, close to the Vatican. The double track railway tunnel has an internal diameter of 9.44 m and a length of 2.410 m. It runs through completely differing soil conditions. (Fig. 1) The first 1000 t are situated in watertight clay, the rear part in water bearing loamy, clayey sands with interlayers of loamy clays. The figure shows the soft change-over from clay to sand. The groundwater head is between [ ]

Jan 1, 1983

By T. S. Golosinski

Most of the 154 t (170 st) truck fleets that were predominant in large surface mines in the 1970s and 1980s are approaching the end of their economic life. One replacement option considered by mine operators is a change to the 2 18 t (240 st) trucks. A comparison of load capacities between the 1.54 t (170 st) and the 2 18 t (240 st) trucks indicates a large productivity advantage in favor of the 218 t (240 st) trucks. This advantage, however, is often reduced by a number of site-specific factors. Therefore, a careful evaluation is required to define the actual benefit of changing to the large trucks. This article discusses some important factors that have an impact on truck size selection, based on several different studies. 218 t (240 st) trucks The 2 18 t (240 st) rear dump trucks were first introduced for surface mine service almost 10 years ago. However, it is only during the last few years that this equipment has gained acceptance in the surface mining industry. About 250 units were employed in surface mines worldwide at the beginning of 1992, and further purchase commitments are being made. Encouraged by the mining industry’s interest, all major off-highway mining truck manufacturers now offer 218 t (240 st) models (Table 1). At present, the existing 218 t (240 st) truck fleets are dominated by electric drive trucks. However, recent introduction of a 2 18 t (240 st) mechanical drive truck rounds out the development of this truck size.

Jan 1, 1992

By George Mandarakas, Johan van Zyl, Karl-Heinz Becker

The world’s climate today has changed compared to 10 or 20 years ago. Many countries face water shortages; water sourcing for mining activities has become harder to secure. ESG’s focus on the industry has made us more aware of the need to preserve and responsibly use the water needed for wet processing in our milling and sorting activities. In a recent greenfield project in South Australia, 10 Gigalitres per annum would be required to process 5Mtpa of magnetite [1]. Published information indicates that the mining industry consumes approximately 12 EJ per year—or 3.5% of total global final energy consumption globally [2] or 3.33 trillion kilowatt hrs. This energy consumption is significant, considering the critical role mining plays in extracting and processing essential minerals for economic development and human progress. The perception of the mining industry is that not only does it consume significant power, but it also consumes a lot of the freshwater in the world. In fact, it consumes approximately 5% [3] of the total freshwater demand. According to the Intergovernmental Panel on Climate Change (IPCC), by 2050, 60% of the world’s population will be living in countries that are classed as water-stressed [3]. As more and more emphasis is placed on renewable energy sources, the amount of water used in mineral processing will increase because more and more raw materials require a water-intensive process. This increases the pressure on the mining industry to try and find water-saving initiatives. As part of this review, recent advancements in magnets have enabled magnetite processing facilities to achieve between 30 to 40% dry gangue material rejection before the wet beneficiation process (grinding and sorting). This reduction in energy consumption allows the reduction of energy consumption. Secondly, there is less material ground in the mills, which requires less water for mineral downstream processing.

Feb 1, 2025

By Nicholas S. Lynn

Introduction Borne out of the need for reductions in capital expenditure and increased production, several new and innovative carbon systems have been developed for small precious metal heap leach operations throughout the United States. Perhaps the most important aspect of these systems is the carbon column. Though diverse in design, these columns can be categorized into three basic types. The first is known as the gravity flow type or Cortez type. As the name indicates, solution flows via gravity, throughout 4 to 6 columns which are arranged in a normally stepped con- figuration which is conventionally upflow in design. The second type, known as the vertical column, is an arrangement whereby flow is established through pressurization in an upward manner, throughout 4 to 6 columns in a vertically stacked configuration. This arrangement is typically intended for use with small portable heap leach operations and employs a semi-continuous mode thus preventing gravity from occurring. The third type and newest development in carbon columns is an arrangement whereby the solution flows throughout 4 to 6 columns placed in a side by side configuration and pressurized by a single feed pump (Figure 1). A unique aspect to the third type, is that the adsorb and desorb cycles are accomplished in the same column, due to a fixed carbon charge. An in-depth analysis is warranted due to numerous advantages of this arrangement, and is therefore the subject of this paper. Advantages and Variations One advantage to the third type of carbon column is the fact that initial capital expenditures and operating man- power requirements are reduced. Another advantage is that the system can be made fully portable up to a 0.0315 m3/s (500 gpm) capacity. Systems of this nature are operational at several sites. Above this flow rate, the system's portability is one which can be maintained, but disadvantages (i.e. larger diameter carbon column and greater weights) far outweigh the advantages. There are several variations in each of these systems which allow for unique operation. For example, carbon columns made highly portable, can be moved from unitized heap leach operations to central stripping facilities. Although this method has been used in Colorado, transportation of these units has been known to be quite cumbersome. If distances exceed 5 km (3.2 miles) then special front-end loaders are required. This limits heap locations to within 5 km (3.2 miles) of the central processing facility. Another example transports the carbon charge from the heap leach locations to a centralized processing facility; this method is quite effective. For the past 5 years one mine has employed this technique of transporting carbon in 907 kg (1 ton lots), in DOT containers, towed by company pick-ups. This operation uses a vertical column with a 907 kg (1 ton) carbon charge. A third example uses static carbon columns with fixed carbon charges. Carbon Adsorption System The carbon adsorption system (Figure 1) is fed by a single preg solution feed pump. This feed pump pushes the preg solution through all four to six fixed charged carbon columns, which are on line. The sequencing of the carbon columns is achieved using valves. Expansion of the carbon charge is dependent upon the carbon selected. The carbon typically used is a 6 x 12 mesh size, with a nominal flow rate of 0.00135 - 0.00138 m 3/s (22-25 gpm) per square foot of carbon, based on a 40% bed expansion. With 8 x 16 mesh size,

Jan 1, 1987

By D. R. Spears

Conventional round tank thickeners have been widely used in the mining industry for many years. The mining industry was well satisfied with the ability of conventional thickeners to improve minerals beneficiation operations. However, development of improved flocculants (the polyacrylamides) made possible much more rapid settling rates, since polyacrylamides produce large flocs rapidly (unlike starch or inorganics). Traditionally considered to be a slow operation if maximum underflow density was achieved, and therefore there was some justification for the expense. Thickeners required large volumes to permit sufficient time for settling. The oversize not considered a drawback but the initial capital cost was. In high rate thickeners, a bed of thickened material is allowed to build around the feedwell, even above the bottom of the feedwell. The slurry is fed directly into the bed at a velocity that allows the material to be evenly dispersed over the thickener area This more efficient use of settling area allows a higher solids throughput per unit surface area (rise rate). In this paper, high rate thickener rise rates and polymer consumption are compared.

Jan 1, 1998

In conjunction with steady increases in production levels, longwall operators have applied greater quantities of ventilating air and spray water in an effort to control respirable dust and/or methane. Air velocities greater than 7.6 m/s (1,500 )fpm) have been measured on longwall faces. Operators have expressed concern over the potential entrainment of respirable dust at these high velocities. The greatest likelihood for entraining dust into the high-velocity airstream may occur as shields are advanced, allowing relatively dry particles to fall from the shield canopy directly into the airstream. Laboratory tests to simulate dust liberation during shield movement were conducted at the Pittsburgh Research Laboratory of NIOSH at velocities ranging from 2.0 to 8.2 m/s (400 to 1,600 fpm). Airborne dust samples were obtained with personal impactors to quantify the size distribution and concentration of the dust entrained at the various air velocities. Statistically significant increases in both total and respirable dust concentrations were measured as test air velocities were increased.

Jan 1, 2002

By ERIK CHARRIER, HUGH MILLER, JOSEF BOURGEOIS

In this study, a unique excavation system was characterized, utilizing waterjet technology as the primary tool for material removal during rehabilitation of reinforced concrete and shotcrete structural liners. Through empiric testing, this research seeks to validate the hypothesis that waterjet removal of these support systems will result in less unintended damage than conventional removal methods. The intent is to develop a viable technology that will reduce the collateral damage caused to surrounding liners during excavation, improve the adhesion between shotcrete and the substrate for longer lasting ground support, and improve overall safety for workers in underground environments. An analysis on the fracture mechanisms and operating parameters of each method was completed. Instrumented shotcrete panels were physically tested and examined through visual inspection and ground penetrating radar (GPR) to compare substrate damage according to each testing method. After testing was completed, the data strongly indicates that waterjet cutting causes less collateral damage to the surrounding intact liner and substrate when compared to that of conventional impact hammers. This research is intended to provide a scientific basis for additional applied research in the rapid excavation and repair of shotcrete support systems.

Sep 23, 2021

By Brianna Eiter, Max Barham, Tim Bauerle

Fatigue-related risk is a persistent safety concern for the mining industry. However, fatigue and sleepiness are often treated interchangeably, which can lead to confusion and potentially less effective reduction of safety risk. To provide clarity, we present an overview of similarities and differences between work-related fatigue risk and sleepiness including definitions, theories, measurements, and mitigation strategies. As a supplement, a summative visual model which highlights these similarities and differences is presented. Expanding industry knowledge in this area will assist safety professionals in crafting more targeted risk management practices appropriate for work-related fatigue risk, sleepiness, or both.

Dec 19, 2023