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By J. J. Gusek

There are hundreds of passive treatment systems accepting mining influenced water (MIW) throughout the world. Some systems do not perform to design expectations while others, including volunteer systems, have successfully operated relatively unattended for decades. The primary reasons for this situation include the common misconceptions that (1) a “cookbook” approach to design is valid for a wide array of MIW chemistries and site conditions, and (2) low maintenance means “no maintenance.” Passive treatment systems for MIW are typically manmade ecosystems that are designed to handle a specific range of metal loading conditions and MIW geochemistry. Thus, when design conditions are exceeded, the suite of microbial to macroscopic ecosystems may be slow to recover or mature. This should be no surprise to designers. But when a particular system fails, it may be inappropriately attributed to the technology, not the design. This paper presents a standard “phased” design protocol that appears to work and provides examples of sub-par performance of selected passive treatment systems.

Jan 1, 2002

China has made great progress in thick coal seam mining, commonly characterized by longwall top-coal caving mining and single-pass longwall mining with a large cutting height. At present, the maximum mining thickness of longwall top-coal caving reaches 20 m while that of single-pass longwall mining approaches 8.8 m. The top-coal caving–related technologies have significantly improved the mining efficiency of thick coal seams and have also made a great contribution to the centralized underground mining of coal. Thus, the number of underground coal mines is greatly reduced in China. However, due to the increase of the mining height and the changes in mining operations, the overburden movement caused by the mining of thick coal seams is more intense, and the influence scope is larger, which brings a series of new problems on ground control of longwall faces. In order to enhance ground control and improve the mining efficiency of thick coal seams

Jul 28, 2020

By John Trefny

Although mining is currently one of the smallest academic units on the Colorado School of Mines(CSM) campus, it is alive and well, with nearly 100 undergraduate and graduate students. For many years, Mines has had undergraduate and graduate programs in hard-rock mining. The school has recently transferred its physical mineral processing activities to the Mining Department. The program has also expanded to include tunneling, underground construction and industrial minerals. There are current discussions about increased research activities on cement and other construction materials. The Mining Department also teaches its share of what is called the “distributed core” courses with curricular requirements common to related programs, as well as mining safety and health, in conjunction with our continuing education department.

Jan 1, 2002

By Thomas V. Falkie

In bygone days, the mineral engineer spent most of his/her time on the technical aspects of designing, building, and managing mineral operations. In the last few decades, mostly since the 1960s, increasing amounts of engineering man power and time are spent dealing with federal, state, and local government agencies, laws, and regulations. It is not possible to plan, design, build, or operate mines, mills, smelters, or even office buildings without detailed consideration of government regulations and permitting requirements dealing with environment, worker health and safety, etc. The four chapters of this section provide an overview of the social, legal, political, environmental, and health and safety aspects of mineral enterprise. The section sets the stage for the working engineer/geologist in industry, government, consulting, or academe and points the direction for more detailed study in each of these areas.

Jan 1, 2008

By Jr. Pitts

Elevation of surface charge density on colloidal particles in the presence of a high potential electrostatic field is demonstrated as a viable technique for preventing the accumulation of solids in solvent extraction circuits. The effect of the technique is manifest by relative turbidity measurements between pregnant leach solution and raffinate, by changes in the character of the sludge accumulations, by alteration of the zeta potential of particulates, and by a general reduction in the mass of solids.

Jan 1, 1992

By J. Wagner, P. Eger, G. Melchert

In 1991, LTV Steel Mining Company decided to close an open pit taconite mine in northeastern Minnesota, using a passive treatment approach consisting of limiting infiltration into the stockpiles and wetland treatment to remove metals. Over 50 million metric tons of sulfide-containing waste had been stockpiled adjacent to the mine during its 30 years of operation. Drainage from the stockpiles contained elevated levels of copper, nickel, cobalt and zinc. Nickel is the major trace metal in the drainages, and prior to closure annual median concentrations ranged from 1.5-50 mg/L. Copper, cobalt and zinc are also present but are generally less than 5% of the nickel values. Median pH ranges from 5.0 to 7.5, but most of the stockpile drainages have pH greater than 6.5. Based on the chemical composition of each stockpile, a cover material was selected. The higher the potential a stockpile had to produce acid drainage, the lower the permeability of the capping material required. Covers ranged from overburden soil removed at the mine to a flexible plastic liner. Predictions of the reduction in infiltration ranged from 40% for the native soil to over 90% for the plastic liner. Five constructed wetlands have been installed since 1992, and have removed 60-90% of the nickel in the drainages. Total capital costs for all the infiltration reduction and wetlands exceeded $6.5 million, but maintenance costs are less than 1% of those for an active treatment plant. Since mine drainage problems can continue for over a hundred years, the lower annual operating costs should pay for the construction of the wetland treatment systems within seven years.

Jan 1, 1999

By Maurice Deul

For the first half of the 21st century, the United States will rely on the same mix of fuels it has for the past 50 years. Petroleum for the United States will cost more and availability will decline as developing nations modernize. Increased use of natural gas for electric power generation will result in stress on the gas supply. Coal will be the fuel of last resort. More than half the petroleum used is imported, about the same amount as used for transportation. Only coal can provide relief by fueling railroads through electrification while encouraging “piggy-back” trailer haulage, co-generation for manufacturing and expanded passenger service.

Jan 1, 2002

By Silvano Morelli, Giovanna Cassani, Renzo Bindi, Antonio Nicola

More than 70 km of main line and service tunnels have been excavated to date for crossing the Apennines between Bologna and Florence. A new design and construction approach, known as Analysis of the Controlled Deformation in Rock and Soils, (ADECO-RS), was adopted to tackle the extreme heterogeneity of the ground and the particular stress-strain conditions. The goal of this system is to obtain constant and predictable full section advance rates, even in very poor geology, with the highest possible level of safety and reliability. The execution of this gigantic project required the mobilization of 21 job-sites, with the concurrent operation of 30 excavation headings. The global production rates confirm the high quality of the design and the high level of industrialization reached during the construction stage, levels not previously obtained in similar conditions, using other approaches such as NATM.

Jan 1, 2003

By Richard R. Klimpel

During the last 28 years, I have had the very challenging and rewarding experience of working as an engineering professional in a large multinational company, both as a manager of engineers and engineering projects as well as an inventor and generator of new engineering processes and products. Due to the diversified geographic and tech¬nical nature of my employer's business, my responsibilities have taken me all over the world. This has included interactions with people in different industries including minerals, coal, chemicals, petroleum, pulp and paper, agriculture and pharmaceuticals. As diverse as my experience may seem, it has always amazed me how common the basic underlying technology and economic trends are that shape the working environment that any given engineer in any given geographic loca¬tion will experience. I would like to discuss the industrial evolution from micro to macro engineering. One of the basic truths behind how industry must and will operate is "change," including: • the creation of conditions for change, • the anticipation of change, • the resistance to change, • the rewards that being part of a change can bring and • the destruction that change can bring to the unprepared. This fact was well stated by Heractitus around 500 BC.: "There is nothing permanent except change." This simple truth has been valid since the dawn of time and, if anything, is accelerating in nature every decade.

Jan 1, 1993

By H. K. Lin

Deepwater discharges of sulfide flotation tailings have been practiced for several decades. Oxygen penetration and organic matter content in such environments are the two major factors that determine their reduction-oxidation condition and hence the rate of sulfide mineral dissolution under such discharge environments. In this study, the effects of solution redox potential and pH on the dissolution of some heavy metals from sulfide flotation tailings were examined. Zn, Pb and Cu concentrations in solution were all higher at a higher redox potential and lower pH. Dissolved Zn concentrations reached 100 ppm even at a low redox potential of 105 mV and near neutral pH after 33 days. Pb concentrations were below 2 ppm at 105 mV and near neutral pH after 165 days. At 105 mV, the Cu concentrations were below 0.2 ppm at near neutral pH after 165 days. At pH 2.3, the Fe concentrations were higher at 420 mV than at 105 mV. But at pH 6.8, the Fe concentrations were lower at 420 mV than at 105 mV, due to the oxidation of Fe2+ to Fe3+ and the subsequent precipitation of ferric hydroxide. Arsenic concentrations in solution were all less than 0.002 ppm. For Zn, Cu and Fe, no significant differences were observed between the tests in solutions prepared using seawater and those using distilled water. However, Pb concentrations reached higher levels in solutions prepared using seawater.

Jan 1, 2009

By E. Fernandez

HIGH SPEED RAILWAY NETWORK Spain is a very adequate country to develop the high speed railway network thank to its geographical feature which has a 600km long radius, from Madrid- the capital that covers mostly the whole country. Therefore, the railway is a major competitor of the airline. In Spain, the new access to the north and northwest is nowadays the most important railway project which will allow a significant saving of time in the near future to the central plateau and the northern territories. Time savings as well as strict environmental considerations have been the main objective of various studies during the last decade leading to Guadarrama and Pajares tunnels as ones of the optimum solutions. Cordoba-Malaga high speed railway, the extension of the present Madrid—Sevilleline, through the Abdalajis range and the rail project to cross oriental Pyrenees between Spain and France are another two samples of large tunnels currently underway. In these four projects, the ground already encountered and to be soon encountered is highly variable, from very hard granite and gneiss in Guadarrama and Pertus to very poor argillite in Abdalajis, shale in Pajares and schist in Pertus. A number of faults are also expected. Hence, double shield hard rock TBM has been chosen. Figure 1 shows a general scheme in four projects. These four projects represent a total of 2 × 68 km of which 87 km are under DRAGADOS contracts. PROJECTS UNDERTAKEN BY DRAGADOS Guadarrama Tunnels This project is the longest twin tunnel with 28.377km, in Spain and considered one of the longest in Europe. The operating speed will be 300 km/h. This tunnel will link Madrid and the north territories through Guadarrama range. (Figure 2). The south portal is placed at el. 997.8m above the sea level. The tunnel starts with an inclination of 3‰, increasing until 15‰. After 6,620m length, the tunnel passes under the Morcuera ridge with an overburden of 960m. After 13,400m length, the elevation is 1,024m which is the highest point, and then the tunnel declines with a slope of 9.5‰, 2‰ and 19‰ until the north portal in Segovia province. At the border of Madrid and Segovia that is Penalara peak, the maximum

Jan 1, 2005

By Tim M. Benson, Adam L. Lamanna, Carolina Martinez-Gutierrez, Mark J. Stephani

The Lower Concourse C Extension (LCE) 108-in Storm Sewer consists of a 2,797-foot long, 27 to 55-foot deep, 108-in I.D. storm sewer tunnel. Situated beneath active taxiways and a terminal apron at Hare International Airport (D), the tunnel diverts ows from existing storm sewers located within the footprint of a future satellite concourse. The project was delivered via Construction Manager at Risk (CMAR) as part of Chicago Department of Aviation’s (CDA) ongoing O’Hare 21 Capital Program. This paper presents project details, multiple stakeholder coordination, subsurface risks and challenges, TBM performance, and impacts to existing infrastructure.

Jun 23, 2024

By W. R. Boehme

The test work was done in two parts. In Part I, five 6 x 16 mesh activated coconut shell carbon samples made by four different manufacturers were evaluated as to their gold loading rate and total gold loading. The five carbon samples tested are not identified by manufacturer and are simply designated as Types A through E. Then from the carbons tested, a suitable highly active carbon was selected for subsequent studies on impurity effects upon loading, Part II. Test Procedures The procedures and tests descriptions are given for the ultimate gold carbon loading tests and the dynamic gold carbon loading tests.

Jan 1, 1983

By R. K. Singhal, H. Sahay

Introduction In terms of the world's recoverable coal reserves, Canada ranks 10th, providing 0.6% of the world's total. The US is first with 27.8% and the Soviet Union follows with 24.1%. Figure 1 shows the principal coal mines in Canada. Several provinces contain substantial coal deposits, but the largest deposits are found in the western provinces of Alberta, British Columbia, and Saskatchewan. Conservatively, 90% of the lignitic, 80% of high volatile bituminous, and nearly 100% of subbituminous, and low and medium volatile bituminous coals are located in these three provinces. During the past decade, Canadian coal production of all types increased from 18.8 Mt (2 million st) in 1972, to 25 Mt (28 million st) in 1975, to 61 Mt (66 million st) in 1984. About 38 Mt (43 million st) of this output was classified at thermal and 23 Mt (25 million st) as coking and metallurgical coal (Table 1). The three western provinces currently produce 57 Mt (62 million st) of coal - 95% of Canada's total. The remaining 3.6 Mt (4 million st) (5%) is produced in Nova Scotia and New Brunswick on the east coast. The majority of western coal (98%) is produced by surface mining methods. On the east coast, though, mining is predominantly underground and only 15% is produced on the surface. In 1985, Canada exported close to 28 Mt (30 million st) of metallurgical coal and thermal coal. During the same period, 15 Mt (16 million st) of coal were imported, mostly from western US for use in Ontario and Quebec. Almost 60% of the imported coal was used for thermal applications. The remaining 40% was metallurgical coal for the steel industry. It is generally cheaper to import coal into central and eastern Canada from the eastern US to augment local supplies rather than from western Canada. This is mainly because of high transportation costs. Mining methods The suitability of mining methods in a particular area depends largely on the geological setting. Geology, therefore, simplifies or adds complexities to mining operations, directly affecting the economics. It also influences the flexibility required from the min-

Jan 9, 1986

By S. Christiansen, G. R. Winslow, R. W. Kobler

Todays End of Life vehicles are shredded and their metal components recovered and recycled by standard methods. The remaining non-metallic fraction is shredder residue, and contains vast amounts of high value engineering plastics. None are today recovered. Discussed are the developmental approaches used in the first process to recover these valuable plastics. Examined are initial laboratory studies, pilot plant design and construction, product development, results, and flowchart explanations.

Jan 1, 2001

By Ian Martin

A precious metals refinery’s switch to personal computer-based, three-dimensional piping design saved many hours in the design of a South African precious metals refinery. Bateman Minerals and Industrial provided engineering, procurement and construction management services for Impala Platinum Limited-Refineries’ new $60 million refinery in Springs, South Africa. This project is one of the largest platinum refineries in the world. Bateman evaluated a new design method during this project that involved developing a three-dimensional model for the project. The new method saved time by reducing the man-hours required to generate complete project documentation, including plans, sections, isometrics and material takeoffs. The new method also saved design and construction time by allowing designers to detect clashes before construction began.

Jan 1, 2000

By M. Deutsch, E. González, M. Williams

"There is uncertainty in ultimate pit limits due to geologic variation and unpredictable economic landscapes. In this work we show how this uncertainty affects the ultimate pit and how it can be analyzed to improve the mine planning process. A stochastic framework using geostatistical simulation and parametric analysis is used to model the effects of geologic and economic variation on ultimate pit limits and overall project economics. This analysis is made possible by a new, highly efficient pit optimization implementation which can be automated and set up to calculate ultimate pits for hundreds of different scenarios in a matter of hours. Quantifying ultimate pit uncertainty early in the mine planning process allows mining engineers to make informed decisions regarding infrastructure placement, and to mitigate the possibility of incurring substantial costs relocating critical mine facilities. INTRODUCTION The mining industry is increasingly concerned with the effects of risk and uncertainty. Uncertain prices, unpredictable global markets, and unknown foreign exchange rates can alter the economic viability of a mining project in substantial ways. This economic uncertainty is compounded by geologic uncertainty. The extent and quality of any given deposit cannot be fully measured and is not known before consequential decisions must be made. These two sources of uncertainty are responsible for the majority of deviation between what happens during operation and what was initially planned. Understanding and explicitly quantifying this uncertainty will lead to better decision making and allow mining engineers and investors to be aware of what may occur. It is unrealistic to believe that one model, estimated from sparse measurements, is enough to capture both geologic and economic uncertainty and allow for optimal decisions. The entire breadth of uncertainty should be considered, as both upside and downside risks have large impacts on the investment potential and operational efficiency of mining projects. The workflow presented here uses Monte Carlo simulation and parametric analysis together to explicitly analyze the breadth of geologic and economic uncertainty as it applies to ultimate pit calculation and long range mine planning."

Jan 1, 2015

By Helmut Hass, Michael S. Shultz

For many tunneling, deep shaft and deep excavation projects ground freezing is one of the best if not the only technique available to create a watertight and load bearing temporary support system in soft ground conditions. When appropriate attention is given to the details of the ground freezing system design, ground freezing is a very safe method and is economically viable with competing techniques and combinations of techniques. Recent innovative uses of the technique in Europe are highlighted in this paper and compared with current uses in North America.

Jan 1, 2005

By Wedam Nyaaba, Samuel Frimpong, Bruno Ayaga Kansake, Irene Akalanyaba Ateng

Haul truck capacities have increased due to their economies of scale in large-scale surface mines. These high-capacity trucks impose dynamic loads on haul roads. A previous study estimated the dynamic forces imposed by ultra-large trucks on haul roads to be more than three times the static load. These dynamic forces exacerbate haul road stresses and deformation. Current haul road response models are 2D and use static truckloads for low-capacity trucks. No models capture the ultra-large truck dynamic effects on haul road structural response. This study uses 3D finite element (FE) modeling to compute the haul road response to ultra-large truck dynamic loading. The dynamic forces were modeled using multibody dynamics (MBD) in MSC.ADAMS. These forces were used in an FE model developed, verified, and validated in ABAQUS, to simulate the response of the haul road to the dynamic truck forces. The road was modeled using an elastoplastic Mohr-Coulomb model. The results showed that road deformation decreases with increasing layer modulus and increases with increasing payload. Increasing the base modulus from 100 MPa to 450 MPa reduced the maximum deformation from 258 mm to 62 mm. When the subbase elastic modulus increased from 100 MPa to 500 MPa, the maximum deformation decreased from 160 mm to 84 mm. Increasing the payload from 0 to 120% of the rated load increased the maximum wearing surface deformation from 131 mm to 216 mm. This study forms a basis for designing structurally competent haul roads for improving haulage efficiency and truck and operator health.

Jan 7, 2023

By Remo Grandori, Manfred Jaeger, Fabrizio Antonini, Luis Vigl

The EVINOS-MORNOS tunnel project with its 30 km of length is one of the longest hydraulic tunnel in the world realised with TBM method. The adverse geological conditions, the high cover and the short construction schedule were a great challenge for the successful construction of this tunnel. The paper will describe: the criteria adopted for the tunnel design, the selection of the construction methods and equipment, the productions of the 4 TBMs adopted and the comparison of the behaviour of the different type of TBMs in the various rock conditions, including special conditions, the characteristics of the adopted in situ and precast linings, a comparison between the foreseen and actual construction schedules, the contractual implications of realising a tunnel in such a severe and complex conditions.

Jan 1, 1995