Search Documents

By Brian Young, Ben Pantony

Interferometric Synthetic Aperture Radar (InSAR) has played an integral role in many large scale tunneling projects globally. Until recently, it has been regarded as a complementary monitoring tool. On the Los Angeles Metro Purple Line Phase 1, InSAR was proposed as a primary means to replace weekly and bi-weekly surface monitoring requirements on surrounding critical infrastructure. This paper will summarize the statistical analysis approach engaged in order to compare and contrast a year of historical InSAR data to known geodetic survey data, in order to utilize InSAR as an operational monitoring tool on this project.

Jun 13, 2021

The need for an integrated approach to optimization of unit operations in both the pit and the mill has long been recognized, but the complexity and nature of the overall problem has up to now resisted solution. This paper reports on a modeling methodology which couples symbolic and numeric computing to unify operations in both the pit and mill. The ultimate goal of this work is to optimize all operations that are influenced by blasting. Blasting plays a key role in all facets of operations. Obviously, drilling and blasting costs are determined by blast design, but the down-stream costs that are closely related to blasting results are often treated as separate functions: loading, hauling, cleanup, and crushing and grinding are all heavily influenced. Diggablilty and bucket fill factor are a function of fragmentation, the condition of the floor and uniformity in the shape of the muck pile. Likewise, cycle times and loading delays partially determine haul cycles, while fragmentation distribution and size determines the efficiency of truck loading. Removal and breakage of oversize causes loading delays and increases cleanup costs. The influence of blasting doesn't stop at the crusher. Mill productivity, power consumption, and maintenance are a function of the feed. Even at the SAG mill a reduction of a critical particle size during blasting can increase throughput. Thus, a bottle-neck for production far removed from unit operations in the pit can be alleviated by a modification in blast design. The question is: how do we optimize blasting with respect not only to itself but to al\ related mining and milling operations? For that matter, how do we even model blasting so that we can control the results of a blast?

Jan 1, 1991

By C. A. Holley

Agitative agglomeration is a rapidly expanding field related to many chemical processes. This paper reviews many processes and the particular type of agitative agglomeration that is utilized with each. Many new innovations to produce granular products in place of powder are explored. The operation and theory of the many types of agitative agglomeration equipment is reviewed.

Jan 1, 1988

By Z. Scopa, E. Tarshizi, R. Setterlind, L. Frost, R. Livernois

"THE MINES OF THE FUTURE The mines of the future present a host of challenges, which may appear exciting or daunting depending on one’s perspective. Whether some sectors of the public recognize it or not, the demand for raw resources is not going away any time soon. In fact, it is rising as global population grows, urbanizes and attempts to steadily increase quality of life. Yes, at the same time that much of the highly developed world is calling for greener goods, reduced consumption, and cleaner production, in other areas there are cries for clean water and sanitation, consistent energy supply, access to health care and education, personal security, and support for basic human rights. The balancing act for sustainable development of our global society is indeed precarious, and the mining community is necessarily a key player. Fortunately, many industry members have accepted this role and the responsibility to provide leadership and a solid foundation for progress. Looking ahead, we need new generations of leaders, many of whom will be mine engineers, which are ready to tackle all sorts of complex problems. There are tremendous needs just for technological innovations. Increasingly tough deposits will require that we continue to expand scale toward “super” pits and “deep” underground mining fully develop unconventional recovery techniques like in-situ leaching and gasification or deep-sea extraction, and seriously consider off-earth endeavors. Such work will take entirely autonomous equipment; novel separations, processing and recycling methods; and systems that can withstand extreme physical conditions – just to name a few. It will also take a level of systems integration never-before seen in our field, complete with big data issues, sophisticated analytics and modeling efforts, and cyber-security challenges. Moreover, increasingly complex environmental problems will require creative solutions. Addressing issues like pollution control across multiple media, emerging contaminants, optimal management of wastes, selective mining, and shared use of resources between mine operations and surrounding communities and ecosystems are among top priorities. Really, a complete paradigm shift must occur, such that our focus is on overall improvement of environmental conditions, rather than minimization of impacts. A similar shift will be required in the social realm. How can we make miners safer and healthier on-site and off? How can we contribute to communities such that they are better off, now and long-term, for having a mine next door? How can we help transform artisanal mining practices to also contribute to sustainable development? How can our work be a factor in increasing economic and political stability? How can we improve the public understanding of raw resources and the need for mining enterprises?"

Jan 1, 2017

By J. L. Yordan

An induction time apparatus has been constructed in the present work which has a sensitivity limit of 100-150 micro-seconds. The basic unit is similar to the one used by Eigeles and Volova (1960) and Trahar (1983), but it operates with a micro-computer and has a greater sensitivity. Using this apparatus, the flotation chemistry of the quartz-amine system has been studied. It has been found that at a given dodecylamminium hydrochloride concentration, the induction time is at a minimum at approximately pH 10.5. At this pH, the collector hydrolizes to form neutral amine and the flotation recovery reaches a maximumy,suggesting that iono-molecular species are the surface-active species responsible for flotation. This finding confirms the earlier conclusions obtained using the surface tension (Somasundaran, 1976; Finch and Smith, 1973) and contact angle (Smith, 1963) techniques. The induction time measurements have also been conducted as a function of particle size, collector concentration, indifferent electrolyte concentration and temperature. The results are compared with flotation data, and the activation energies for the bubble-particle adhesion have been calculated.

Jan 1, 1986

By Charles M. Brinckerhoff

Everyone -- especially the engineer -- is aware of the great technological and social changes taking place in our world today, We realize that changes have been taking place since man's beginnings on earth, but the element we now face is the speed of change, rather than change itself. Developments in medicine, in transportation, in space exploration, in global communications, and in many other fields, are constantly being made known. These developments are affecting the lives of each of us, although some may appear remote and unrelated to us as individuals. New developments, almost on a daily basis, affect our work as well as our social, religious and educational lives. The effects are immediate and permanent.

Jan 1, 1967

By Donald M. Duncan

An acceptable source of concrete aggregate is available in Kansas City in a continuous, medium bedded, slightly dipping limestone unit. Removal is accomplished in shallow depth, 12 feet to 17 feet high, room and pillar mines. The accepted empirical design spaces 20 foot pillars 60 feet on center. A portion of the 20 foot unit is left in place for roof support. Rock and soil cover is variable to 100± feet maximum. Long-term stability of these mines is affected by numerous factors, including the above mine-rock profile, ground water conditions and mining practice. Crusher-run aggregate sells at the mine for $2.20 per ton, yielding a gross income of $2.00 to $2.80 per square foot of mine. Use of mine space for real estate development requires a new perspective in mine development. Mining practices to obtain long term stabile structures can become an over-riding factor as compared with minimum production costs and maximum extraction ratios. Poorly mined areas are unusuable for secondary purposes. Development cost for lease space in less desirable mines is substantially greater than those planned for a secondary use. Real estate development in mine space involves unique engineering problems. Properly engineered developments offer singular advantages. Warehouse lease space sells for $.50 to $1.00 per square foot per year; fully developed office areas may double these values.

Jan 1, 1968

By A. Röttger, W. Theisen, J. Küpferle, M. Alber

"Wear of TBM tools significantly affects tunneling advance rates. Wear-prediction models are based (amongst others) on the abrasivity of the present geology, which is determined via laboratory tests. To evaluate the results from such tests in context, this work considers the tribological system TBM tool from a materials technology perspective. In so doing, the microstructures of different application-oriented materials are presented and discussed in terms of their wear behavior and wear resistance. The significant influence of tool materials on the abrasivity of the geology and thus wear prediction models has already be identified. LCPC, Cerchar and nano-scratch experiments have been performed as confirmation. Material-dependent wear mechanisms and their correlation in terms of tunneling have shown that it is mandatory to consider the complete tribological system to estimate the wear of TBM tools. 1 INTRODUCTION Mechanized tunneling is vital to ensure necessary infrastructure development in megacities like Tokyo (Bay Tunnel), Istanbul (Eurasia Tunnel) and Mexico City (Tunnel Emisor Oriente). The use of Tunnel Boring Machines (TBMs) has been established for many years. In contrast to other methods such as boring and blasting or excavation using dredgers, tunneling with TBMs allows simultaneous excavation and removal of both the mineral and tunnel lining by tubbing segments or shotcrete. This makes tunneling more efficient, allowing for faster development of the tunnel in both hard rock and soil [1]. When budgeting such tunneling projects, precise planning and coordination in terms of tunneling technique choice (e.g. EPB or Slurry-shield), the relevant geology, and the associated penetration rates and tool wear are required. In particular, wear to TBM tools has a significant impact on tunneling progress. Due to wear, tools become dulled or lose their functionality because of brittle material behavior, thus reducing penetration rates and therefore tunneling efficiency [1]. As a result, additional tool changes are necessary, leading to higher overall costs due to down times and maintenance costs. Therefore, there is strong interest in a reliable and precise wear prediction model for TBMs. As already mentioned, the geology and associated wear of the tunneling tools define the maintenance times."

Jan 1, 2016

By John Kuyt, Zili Li, Michael Mooney, Michele Mangione

"INTRODUCTIONTwin bored tunnels are commonly used for a variety of road and tunnel projects throughout the world. A major component of these twin tunnel projects is the construction of connecting cross passages that provide emergency access between tunnels and space for tunnel service equipment. Cross passages can present significant geotechnical risk and technical challenges to a project – support systems must be considered for redistributing loads around the mainline tunnel openings and supporting new loading resulting from excavation activities. Additionally, cross passages pose risks to construction schedule and cost because of their sequencing at the end of construction, so mitigation of schedule overruns can be critical. By observing field instrumentation data records from completed projects, a betterunderstanding of the force development in each temporary structure can be achieved with indication of which structures are the most critical to support ground loads.This paper discusses the data obtained during the Brisbane Airport Link construction project, a road tunnel located in Brisbane, Australia. Strain gauge instrumentation data from the precast segmental lining and propped opening steel sets is presented with relation to the construction sequence and local geology. Interpretations and conclusions based on the observed trends are proposed, with several key mechanisms affecting the loading and unloading identified.Brisbane Airport Link Project OverviewThe Brisbane Airport Link project in Brisbane, Australia, connects central Brisbane to the airport located northeast of the downtown with over 7km of twin-bore road tunnels, two lanes each, with several caverns, interchanges, and access ramps constructed along the alignment to connect to other key routes in the city. The project was executed under a Public-Private Partnership (P3) scheme, funded and operated by the consortium BrisConnections. The main contractors were a joint venture of John Holland and Theiss, while the design was carried out by Arup and Parsons Brinckerhoff.Construction of the tunnels was conducted using a combination of 17 roadheaders and two 12.5m double-shield Herrenknecht TBMs [1]. The TBMs were used in EPB-type closed mode for the initial portion of their drive, starting at the northeast end of the alignment. Tunneling started in soft ground, weathered rock, and mixed face conditions initially, progressing to competent sedimentary rocks as the drive continued. Support was accomplished using a 12.1 m diameter steel fiber reinforced concrete (SFRC) segmental lining installed behind the TBMs in a 9 segments + 1 key arrangement. The innovative design of these segments is detailed in the paper by Harding and Francis [2]. Ancillary roads and underground interchange caverns were constructed by sequential excavation techniques using roadheaders, accounting for nearly half of the total underground excavations."

Jan 1, 2016

By Marcel Laflamme, Sebastián Ibarra‑Gutiérrez

Improvement on controlling the stope limits has enabled the assessment of technical performance in several underground mining operations. Technical performance, integrated to stope geotechnical and geomorphological parameters, constitutes the basis which guides mining engineers in the Mineral Reserves Estimation process. Moreover, there are established definitions to report this information in Canada, incorporated in NI 43–101, which stipulates that “A Mineral Reserve includes diluting materials and allowances for losses that may occur when the material is mined” [1]. However, some loopholes have been identified regarding practical standards followed to specify the way to include and report ore losses when the lost material was blasted and must be left behind unrecovered inside the stope. In fact, general efforts to estimate and quantify the negative effects of operational ore losses only consider under-break ore loss. However, mining engineers frequently confront situations requesting the anticipated closure of a stope. Therefore, reconciliation process should reflect the amount of unrecovered Mineral Reserve. This work presents a discussion of possible practices to integrate adequately operational ore losses consisting of blasted but not recovered material and focuses on how different approaches regarding the material constitution could severely affect the stope technical performance interpretation.

Aug 9, 2021

By Horace M. Varner

Under sponsorship of the USBM and later of the DOE, a new type of rotary rock drill has been developed by The Bendix Corporation. Originally developed for the production of holes for the installation of longer than seam height roof bolts, the flexible drill is a useful tool for many drilling applications. This drill allows hands-off or remote production of holes for increased drilling speed and greater operator safety in any strata suitable for rotary drilling. The paper discusses various applications and experience for the flexible drill system in coal mining, metal/nonmetal mining, and for general civil engineering uses. Manual, remote control, and automatic roof bolter modules are also discussed.

Jan 1, 1982

By E. Watkins, V. Gangrade, P. Zhang, J. Addis, D. W. H. Su, T. Minoski, C. Hollerich, M. Van Dyke, S. Schatzel, H. Dougherty

"This paper presents the results of a comprehensive study conducted by the Centers for Disease Control (CDC), National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Mining Research Division (PMRD) to evaluate the effects of longwall-induced subsurface deformations and permeability changes on shale gas well integrity and safety under shallow cover. NIOSH researchers selected a study site over a southwestern Pennsylvania coal mine, which extracts 1,500-ft-wide longwall faces under 482 feet of cover. One in-place inclinometer well and three permeability monitoring wells were drilled and installed over a 125-ft by 275-ft centers abutment pillar. In addition to the inclinometer well and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the first 1,500-ft-wide longwall panel on the south side of the abutment pillar mined by the site.A number of FLAC3D finite difference simulations (Itasca Consulting, 2017) were conducted to estimate surface subsidence, coal pillar pressure increases, and horizontal displacements in the in-place inclinometer (IPI) monitoring well. Comparisons of the FLAC3D finite difference simulation results and the surface, subsurface, and underground instrumentation results show that the measured IPI casing deformations are in reasonable agreement with those predicted by the FLAC3D models, and that the measured surface subsidence and underground pillar pressure are in excellent agreement with those predicted by the 3D models. Measured permeability changes were incorporated into a preliminary calculation to evaluate the effect of a hypothetical shale gas well leak on longwall ventilation. Results from this 2018 research clearly indicate that under shallow cover, the measured horizontal displacements within the abutment pillar are at least one order of magnitude higher than those measured in a 2017 study under deep cover and slightly higher than those measured in a 2014 study under medium cover. This research represents a very important step and initiative in utilizing the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the workers in the oil and gas industries"

Jan 1, 2019

By H. C. Harrell

The Tennessee Valley Authority began employing geophysical well logging for foundation investigations in October 1973. Since that time more than 3,000 holes have been evaluated for engineering purposes. The Tennessee Valley Authority has not actively used geo-physical well logging for exploration of construction materials, but we feel that much of the information derived from geophysical logs for foundation exploration is applicable to the construction materials industry. This paper will then discuss geophysical logging as applied to foundation engineering and, by implication, the feasibility of use in construction materials exploration. The use of geophysical logging and percussion drilling instead of coring has greatly expanded TVA's data acquisition capabilities and has also resulted in substantial savings in time and money. Economical boreholes are obtained through the use of large percussion track drills (Figure 1). This equipment is capable of drilling through the overburden, setting steel casing on the top of rock, and drilling the rock beneath the casing. Holes as deep as 400 feet (121.9 m) have been drilled by this method.

Jan 1, 1977

By F. S. Knoll

The high tension process which separates materials based on relative differences in surface conductivity has been very successful in recovering non-ferrous metals from municipal waste. Aluminum is by far the largest constitutent of the total non-ferrous metal fraction; accounting for >95% in most localities. Wire and insulation mixtures from industrial wastes have been treated commercially for several years by a high tension process initially developed for use in the iron ore industry. The wire and insulation application was a forerunner of municipal waste dry treatment technology. In the past eighteen months the rotating-drum-type electrostatic separator has undergone extensive testing and development in order that the process might be efficiently adapted to the recovery of aluminum from municipal waste.

Jan 1, 1974

By J. G. Groppo

Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 pm) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20 percent level moisture will be an important step in successful implementation of the advanced cleaning processes. This study is a step in the Department of Energy's program to show that ultra-clean coal could be effectively dewatered to 20 percent or lower moisture using either conventional or advanced dewatering techniques. The main focus of the pilot plant study was on proof-of-concept testing of a dewatering technique for a fine clean coal product. The coal industry is reluctant to use the advanced fine coal recovery technology due to the non-availability of an economical dewatering process.

Jan 1, 1997

By Martín A. Encinas-Romero, GUILLERMO TIBURCIO-MUNIVE, María M. Salazar-Campoy, Patricia Guerrero-Germán, José R. Parga-Torres, Luis S. Quiróz-Castillo, JESÚS L. VALENZUELA-GARCÍA

Pressure oxidation is a hydrometallurgical oxidative pretreatment for refractory ores, such as sulfide ores. Here, simultaneous alkaline pressure oxidation and sodium cyanide leaching treatments were carried out on a pyritic ore from the Mulatos Mine located in Sahuaripa, Sonora, Mexico. Mineral characterization, agitation leaching, hot cyanidation under atmospheric pressure conditions, simultaneous moderated pressure oxidation and leaching, and kinetic testing results are shown. The modified variables were temperature, pressure, and cyanide concentration. Characterization indicated that pyrite was the main mineral. Simultaneous pressure oxidation and leaching experiments were conducted at a temperature range of 40–80 °C, oxygen pressure of 87.5–200 psi, and cyanide concentration of 0.8–1.2 wt% in a 2-L Parr pressure reactor. A dissolution rate of 81–86% was achieved under the following conditions: 87.5 psi, 80 °C, 0.8 wt% NaCN, for 1 h.

May 7, 2020

By L. Patts, J. Rohrbaugh

The Mine Safety and Health Administration (MSHA) has received several reports of filters igniting when high-temperature disposable filters were used on non-cooled diesel exhaust systems in underground coal mines. Based on laboratory testing (to determine the ignition temperature of these filters, which were loaded in the field with diesel particulate matter, or DPM), MSHA determined a maximum safe operating temperature for high-temperature disposable filters. When the results of the laboratory filter ignition testing were reported to the Coal Diesel Partnership (comprised of members of the Coal Industry, Labor, NIOSH and MSHA) the Partnership charged NIOSH with investigating the safe use of high-temperature disposable filters. This paper reports on the design, fabrication and testing of a unique exhaust gas cooling device and the ability of this device to successfully lower filter inlet temperatures and thus reduce the potential for fires.

Jan 1, 2009

By James R. Garvey

The impact of conversion on the coal industry can be summarized very briefly: We are going to have to mine an awful lot of coal. Fortunately, the United States has the coal reserves available, and given the right conditions, we can mine it. The coal reserves of the United States are enormous. If we consider them on the basis of proved reserves, using the standards of the petroleum industry--that is, resources mapped and explored and recoverable with present techniques at close to present costs--and compare that with the reserves of other fuels, coal constitutes 88 per cent of the proved recoverable energy resources of the nation. That includes oil, natural gas, oil shale and uranium, so long as the uranium is used in burner reactors. If we consider resources on the basis of "ultimate recoverable" reserves, that is, those resources which can be extracted with improved technology and at somewhat higher costs--and if we include those resources of all fuels not yet found but believed to be waiting discovery--coal still accounts for 74 per cent of the national total. We have built a hydrocarbon economy in which about 76 per cent of our total energy needs are supplied by petroleum and natural gas, and about 20 per cent by coal. Domestic resources of oil and gas are running dangerously low and, assuming a continued hydrocarbon economy, the 20 per cent supplied by coal may increase dramatically. We already import nearly a quarter of the petroleum we consume, and the chief source of additional imports seems to lie in the politically unstable Middle East. Natural gas is in even shorter supply, and the problems of importing it seem at least as difficult as those of oil. The fact is, the United States is already relying to an increasing extent on foreign fuel sources. There is an obvious national risk in making an important part of energy supply hostage to foreign governments of uncertain tenure and friendliness. There is also an economic risk--one of the chief reasons for last year's economic freeze was to try to correct the deficit in our balance of payments; it is obvious

Jan 1, 1972

"INTRODUCTION The characterization of groundwater hydrogeology is a common component in feasibility studies, geotechnical investigations and regulatory permitting for mining operations. The lithology at a location of interest may include several discrete water-bearing units; and the means of isolating each for testing can be accomplished through the use of inflatable packers. Consideration for testing during drilling program planning and communication between all stakeholders is essential to ensure that the Mine, Drilling Contractor and Hydrogeological Testing Specialist (Specialist) are ready to perform packer testing when the call is made to mobilize. Often, the notice to mobilize can be delayed and then occur with little warning due to the issues that can occur during drilling of very deep boreholes, as well as other factors. Hydrogeological investigation reports and journal articles generally discuss testing methods and results, with limited information available describing the planning and coordination of the field testing program, as evidenced by the lack of references cited below. The source of inspiration for the subject matter of this paper is grounded in the author’s past shortsightedness; with the hope that others not share similar misfortunes but experience success through thorough preparation for their future hydrogeological testing programs. The sections below focus on the planning stages of a field investigation using inflatable packers, including considerations for site specific conditions, designation of stakeholder responsibilities, and communication of testing expectations. Following these sections is a presentation of two examples of successful field programs and lessons learned in addressing problems encountered along the way. PRELIMINARY PROGRAM PLANNING & CONSIDERATIONS From the onset of planning for drilling programs, the Specialist should be in communication with the Mine to review plans and identify fatal flaws which could impede collection of hydrogeological data. Preliminary scope decisions can significantly affect the budget and duration of hydrogeological field programs and may dictate the means by which the field data is collected. The issues that need to be considered include the following factors. Testing Objectives The setup of the packer tool is dependent on the testing objectives. Is the goal to estimate bulk aquifer hydraulic conductivity or to identify discrete discontinuity hydraulic characteristics? Are groundwater samples needed? The answers to these questions affect selection of test interval length and what instrumentation might need to piggyback on the packer tool. Identifying the testing goals initially will provide adequate time to prepare packer equipment for mobilization. Borehole Size While inflatable packers come in many shapes and sizes, some sizes are more readily available and easier to procure on short notice. Packers for NQ and HQ size boreholes have been historically easy to procure and are commonly used in exploration drilling. Packer equipment is available for smaller holes, but it becomes more difficult to fit instrumentation down-hole as the borehole size decreases. This is particularly a consideration if collection of groundwater samples is required. In addition, risks of losing the hole or equipment downhole are greater for smaller boreholes. Larger boreholes require larger packers and clearly require more effort and heavier capacity machinery to manually manipulate due to the increased size."

Jan 1, 2017

By W. Lorenz

The responsible treatment of natural resources, including mineral raw materials, contributes to the protection of the environment. The management of resources and the environment encompasses reduction of emission through application of environmentally friendly processes, economical use of resources, recycling and substitution, application of energy saving processes, land reclamation and recultivation, as well as a well balanced regional and land use planning. A variety of materials are needed for measures to protect the environment. Many of these materials are, or to a large percentage consist of, mineral raw materials, which become effective either directly or indirectly in their natural state or after an appropriate industrial treatment. We call them environmental minerals. Although extraction and processing of these mineral raw materials destined for use in the protection of the environment, may have a negative impact on the environment on one hand, preventive or curing measures to protect the environment on the other would not be possible without them. We have to accept certain smaller burdens of the environment, which naturally will have to be kept at the lowest possible level, in order to avoid or minimize greater damages to nature. In the broad group of industrial minerals and rocks there is a wide variety of mineral raw materials, which lend themselves for countermeasures in favor of the environment. To hamper their production and processing through excessive environmental regulations would make the protection of the very environment more difficult or even impossible.

Jan 1, 1995