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By Nathan Painter, Kevin Andrews, Andrew Karpa

Groundwater flow in bedrock units is an important factor to be considered for most mining situations, both underground and open pit excavations. Characterization of the hydrogeologic system into which a mine will advance is an important factor for slope and entry stability, mine dewatering design, and potential environmental considerations including stream loss and water well damage. In addition, hydrogeologic characterization of bedrock is important for locating water wells and for groundwater contamination mitigation. Hydrogeologic characterization for a site begins with a desktop study and often evolves to include drilling, geologic logging, monitoring well installation, groundwater sampling, pump testing, and packer (Lugeon) testing. In addition to these methods of hydrogeologic data collection, downhole geophysical logging of exploration and monitoring well boreholes provides detailed information associated specifically with in-situ conditions of each hole. The basic suite of geophysical logging tools used for hydrogeologic characterization often includes Optical or Acoustic Televiewer (O/ATV), full wave sonic, gamma-density, fluid temperature, resistivity, specific conductance, and flowmeter. For many hydrogeologic settings, groundwater flow in the bedrock is dominated by discontinuities, or fractures, in the rock. O/ATV logging allows for determination of the frequency (clustering), orientation, and aperture width of in-situ fractures, while sonic logging allows for estimation of intact rock strength. Fluid temperature logging and flowmeter measurements provide insight with regard to potential groundwater inflow zones, and other tools provide information for geologic unit contacts. This paper outlines the process and benefits of using downhole geophysical logging for hydrogeologic characterization and provides generalized examples from industry experience.

By Jesse H. Auvil

In January of 1966, during the annual session of Georgia's General Assembly, Representative Paul E. Nessmith of Statesboro, Georgia, walked into my office and asked me what I thought of the advisability and feasibility of a law which would require the mining operators to reclaim their mined out lands. My answer to him was, as a one time mine superintendent and operator, that I probably would not think very highly of the added cost which reclamation would impose on the operation; but that since assuming the job of Chief Geologist and Assistant Director of the Georgia Department of Mines, Mining and Geology, and in retrospect, I could recommend it very highly, particularly in view of the increased pressure being applied by the Federal government along these lines. I stated then and still emphatically state that this sort of administration should be done on the State level rather than the Federal level. He asked me if I would conduct him on a tour through some of the mining country in which I had worked and to this I readily agreed. The result of this trip was that he was adversely impressed by the devastation which the mining operations had wreaked on that area of middle Georgia along the fall line known as the kaolin belt. Very little except talk was done for the remainder of 1966.

Jan 1, 1970

By John R. Riede

Most modern crushing and grinding facilities are automated to some degree. Some, of course, have a very minimum of automatic control whereas others utilize very complex control equipment. However, with very few exceptions, the re has not been a new basic control philosophy applied in this field in the past seven years. The philosophy has been broadened in scope and applied to larger plants, some of them with data logging and so- called computer control, but almost always the same tried and proven basic control philosophy is the basis for the control system. New types of control devices to better implement the automatic control have been developed and are continuing to be developed. These devices and their application will be explained and the advantages and disadvantages of each will be discussed. Automatic lubrication of plant equipment is most essential, but this paper will not cover these systems. The use of data logging and computer analysis of the data obtained is fairly recent and it is hoped that by careful analysis of this information that new and better basic control philosophy will be forthcoming. This paper will describe the basic philosophy applied in its simplest form to several types of crushing and grinding equipment, and it will describe how it is being expanded to more complex systems. Some of the economics with regard to first cost, return on investment and maintenance will be covered.

Jan 1, 1965

By Panshi Xie, Yan Chen, Shaogang Wu, Yang Hang

In order to realize the intelligent mining of coal seam with large dip Angle, this paper adopts the methods of large proportion variable Angle loading threedimensional physical simulation experiment, numerical simulation and field measurement with digital twin technology. The hydraulic support with large dip Angle and large mining height is used as the prototype to design the physical entity model of 1:5 hydraulic support, combined with modeling and graphics rendering technology. Angle, displacement and load sensors were selected and placed to realize the data channel between the lower machine and the upper computer of the digital twin system, so that the position and load data of the physical entity model and the twin model of the laboratory hydraulic support could be shared in real time. Moreover, the multi-dimensional dynamic and static load transfer law and the position evolution characteristics of the support and surrounding rock under different inclination angles were analyzed. The results show that: with the increase of the Angle of the working face, first, the initial support force required by the support decreases, and the damage degree of the roof increases; When the roof is soft, the lifting operation can avoid the instability of the support to a certain extent. Second, under the action of positive pressure, the load of the top beam under different angles is balanced; Under the backpushing action, the load in the upper inclined area of the shield beam increases gradually, while the load in the lower inclined area decreases gradually. Under the lateral push, the load changes periodically, and the load in each cycle is increased compared with that in the previous cycle. Third, the numerical simulation analysis shows that the load on the lower bracket is less than that on the upper bracket, and the load on the bottom of all the columns is greater than that on the middle and upper brackets. In order to reduce the impact of the columns on the bottom plate or the base, it is necessary to improve the anti-subsidence ability of the base. Finally, according to the research results, the improvement and optimization measures of the support are put forward, and the field test shows that these measures effectively solve the problems of sinking, sliding and tipping of the support in the working face with large inclination Angle, and obtain good application results.

Feb 1, 2024

By James A. L. White

Although the quantity of native sulphur associated with volcanism is large, production from such deposits represents only a very small percentage of total world production, This paper describes the location of the known deposits, the typical geology of these deposits and the nature of the sulphur mineralization. Methods of treatment are discussed and some comments are offered on the economic position of these occurences in world sulphur markets.

Jan 1, 1967

By John P. Hunt

Early disseminated copper mineralization at Quebrada Blanca, Chile, accompanied 38 million year old quartz monzonite stocks and dikes. Early mineralization was followed by hydrothermal mineralization, mineralized breccias, and post-mineral faulting. After supergene leaching and enrichment, Quebrada Blanca was buried under late Tertiary gravels, and then partially re- exposed in Quaternary time. Based on work to date the orebody appears to contain more than one hundred million tons of plus one percent secondarily enriched copper ore, overlying several hundred million tons of protore averaging more than 0.5% copper. A source of industrial water appears to have been located. Pilot scale metallurgical tests, mine planning, and feasibility studies are in progress.

Jan 1, 1981

By Loic Galisson

"Urban tunneling projects are usually extensively monitored. Most of the instruments used rely on benchmarks providing a sustainable datum throughout the life of the project. The monitoring program also is based on a predicted model of deformation induced by specific construction methods. Events can interfere with those assumptions and eventually alter the stability of these datum. In addition, the anticipated ground conditions and hence the theoretical deformation model often differ from reality. Satellite Radar Interferometry provides useful information to overcome the weakness of the hypothesis made before construction. It is also a powerful tool to ensure the continuity of the monitoring program throughout the life of the project, accurately describing the true effect of the project on the surrounding environment. This paper emphasizes the benefits and limitations of this technique for urban tunneling applications, illustrated by examples of major tunneling projects around the world. MONITORING URBAN TUNNEL PROJECTS Why Monitoring? Retrofitting existing tunnels or constructing new tunnels – including access and retrieval shafts, portals and cross passages – implies an alteration of the neighboring soil structure. Excavating, dewatering, grouting, loading tie backs, etc. artificially modifies the natural equilibrium of the pore-water pressure, of the water table level and of soil stability. In many cases, the effects are immediate: ground loss, deformation of utilities, settlements of buildings, and distortion of infrastructure are a few examples resulting from construction activity.Instrumentation and Monitoring Scope To control and mitigate the risks of damage associated with the above effects, tunnel projects usually include an instrumentation and monitoring program. Depending on the level of geotechnical, structural and environmental risk, the magnitude of this program varies. Projects with a low exposure to risk may restrain the program to conventional methods such as limited topographical surveys and intermittent manual readings of geotechnical instruments. On the other hand, iconic projects with high risk or with controversial history may implement complex and extensive instrumentation plans, involving highly technical solutions such as Automated Motorized Total Stations (AMTS – see opposite Picture 1), Multi-Point Borehole Extensometers (MPBX), In-Place Inclinometers (IPI) and a wide series of fully automated geotechnical, structural and environmental sensors. In this case, all the devices are usually connected to field data loggers collecting raw data around the clock at frequencies ranging from days to seconds, depending on the sensors."

Jan 1, 2016

By J. A. Madonna

Universities and colleges in three countries, Australia, Canada and the United States, recognized the need to establish and/or reorganize geoscience programs at the vocational and two-year technical levels. To accomplish this goal, a cooperative study with industry in one state or province from each country was initiated. These include 1) Tasmania, Australia, 2) British Columbia, Canada and 3) Alaska, United States. Over one hundred mineral industry organizations cooperated in the study by providing information regarding their specific training needs for support personnel. The data gathered has been used to identify training areas for semi-skilled, skilled and technical personnel in geochemical mineral exploration, including, but not limited to, geological skills, geochemical skills, environmental skills and computer skills. With the areas of major educational need defined for geochemical exploration, an educational field skills model has been developed for the three levels of training. The depth of each level of education and the training objectives for the work force at each level will be discussed.

Jan 1, 1993

By R. A. Haney

The Mine Safety and Health Administration has developed a model to estimate diesel particulate (dp) exposures in underground mines. The estimate uses either in-mine measured dp concentrations or engine manufacturers' standardized emission data and through a series of calculations estimates full shift dp concentrations by applying standard engineering principles of ventilation, control technology and work cycle. This model, in the form of a computer spreadsheet, provides the mining industry with a method to estimate diesel particulate levels and determine the impact of various diesel particulate controls on occupational exposure to dp in underground mines. A detailed description of the estimator and several examples demonstrating the results are provided.

Jan 1, 1998

By Mike Hall, Tim Kelly, Mohammad Reza Jafari, Ulf Georg Gwildis

"Qatar’s capital Doha is undergoing major infrastructure improvements including a multiphase stormwater management program. Although located in an arid climate, Doha experiences flooding during rainfall events. Dewatering operations and rising groundwater levels add to the management needs. To address those needs, construction of the Musaimeer collection tunnel along Doha’s southern rim is being followed by a marine outfall tunnel connecting a pump station to a dispersion field 10 km offshore. Qatar’s geology is characterized by sabkha deposits, a series of predominantly weak and karstic rock strata that creates challenging conditions for mechanized tunneling, as highlighted by the uncontrolled flooding of a tunnel boring machine (TBM) used on the Doha Metro tunnels. Risk associated with these challenges is magnified for the outfall tunnel by drive length, sub-sea elevation, and a single access point. This paper describes the outfall exploration strategy and design decisions made in light of experience gained during the collection tunnel construction. CONTEXT – STORMWATER MANAGEMENT PROGRAM Qatar has an arid climate with an average annual precipitation of less than 100 mm. Precipitation is mostly confined to the winter months when rare, but occasionally heavy rainfall events easily lead to flooding in Doha’s metropolitan area. Its coastal location and flat topography a few meters above the sea level mean that the depth to the groundwater table is generally shallow. The karstic aquifers in the regional dolomite and limestone series contain groundwater of high salinity, which is not suitable as a potable water source. For supplying Doha’s population of more than 900,000 (2014) with potable water, the Ras Abu Fontas seawater desalination plant is operated about 10 km south of the city. This potable water production capacity is crucial for Doha’s development and – in conjunction with overirrigation and leaking sewage tanks – is also the root cause for rising groundwater tables that have been observed over the past years."

Jan 1, 2016

By O. A. Velasquez, A. R. Kumar

"Continuous miners are often equipped with a flooded-bed dust scrubber to clean the air from close to an active underground coal mining face. However, its impingement screen is prone to clogging due to an accumulation of dust, thereby lowering the scrubber’s efficiency and potentially exposing the mine workers to higher levels of dust. Fans can compensate for the increased resistance by varying their operating parameters, but the scrubber screen needs significant maintenance which leads to downtime. The authors have proposed a suitably sized Vortecone as an alternative to the conventional flooded-bed dust scrubber system. Water is used as the filter medium, which is replaced and recycled continuously. Preliminary CFD investigations of Vortecone scrubbers have indicated higher cleaning efficacies, especially in the respirable range. This paper presents the results including the flow characteristics and capture efficacies of a full-scale Vortecone. Multi-phase flows, including free-surface modeling and particle tracking methods, have been adopted. ACKNOWLEDGEMENT The authors acknowledge the National Institute for Occupational Safety and Health (NIOSH) for funding this research project. This research is being developed with the support of a NIOSH Grant 200-2014-59922- ‘Coal Mine Dust Mitigation through Novel Scrubber Development and Numerical Modeling’. The views expressed in this paper are those of the authors and do not necessarily reflect those of NIOSH. This project is aimed at designing novel and efficient scrubbing systems for underground mining operations. The authors acknowledge Dr. Thomas Novak of the Department of Mining Engineering, the University of Kentucky for his support and encouragement. The authors also thank Dr. Sunil Vytala, CFD engineer at Cradle CFD for his invaluable inputs to the numerical models.INTRODUCTION Continuous miners are the main production machines deployed in room and pillar mining operations. These miners extract coal by the shearing action of the wethead cutting drums. Strategically placed water sprays on the drum not only cool the bits extending their useful service life, they also suppress the dust at the point of generation itself. A flooded-bed dust-scrubber (Campbell, et al. 1983) is usually integrated onto the continuous miner to arrest dust from close to the active face. These fan-powered scrubbers have an impingement screen flooded with water, which also serves as the filter element. A demister downstream of the screen removes the excess water from the air cleaned. These conventional scrubbers have been found to be very effective in alleviation of respirable dust levels underground (Chao and De-sheng 2000) (Colinet, Reed and Potts 2013). However, the inefficiencies of the flooded-bed dust scrubbers arise out of their internal components. Depending on the mining conditions, the screen may be clogged by the accumulation of the trapped dust particles. The resistance of the scrubber system is increased reducing the airflow. The flooded-bed dust-scrubber system would, therefore, require frequent maintenance of the screen and the demister (Listak 2010). Since any maintenance needs to be carried out under supported roof, this leads to loss of availability of the equipment as well. In addition to this, the continuous miner operators could be exposed to elevated levels of dust when satisfactory airflow at the face is not achieved."

Jan 1, 2018

By Andy Thompson, Frank Perrone

"As part of the Metropolitan Transportation Authority’s $10.5bn East Side Access Project in New York, 3,200 m of tunnel had to be constructed in rock, mix face and soft ground conditions beneath one of the largest passenger railroad junctions in North America, handling over 780 trains per day. The use of risk based decision making tools was essential in developing the bespoke contract framework that was adopted as well as making informed decisions once excavation commenced. This paper will outline the risk management process adopted, discuss the risks and mitigation strategies adopted and comment on the impacts of this approach on the as built Project cost and schedule. In particular, the paper will outline the unique approach used to establish the baseline against which the Contractors performance would be measured as the selection of a Slurry TBM to excavate the tunnels was considered to compromise the effective use of a Geotechnical Baseline Report. BACKGROUND AND CHALLENGES Contract CQ031, Queens bored Tunnels and Structures was awarded in September 2009 to a joint venture of Granite Northeast/Traylor Brothers/Frontier Kemper (GTF JV) for $717.6m following a negotiated procurement process. A robust approach was taken with regard to the management and payment for risks associated with the construction of these tunnels. Risk assessments were carried out during the design phase and a risk register was developed prior to procurement. During the procurement phase close attention was paid to ensuring that the allocation and pricing of known risks, together with mechanisms for managing future risks were clearly defined between the MTA and GTF JV.In comparison to the excavation work in Manhattan, which was performed in competent hard Manhattan schist, the tunnels in Queens were excavated predominantly through soft ground with a high water table and complex environmental conditions. Not only did this require the use of pressurized face TBM technology, a first in New York, but also a re-evaluation of the contractual mechanisms used to manage the hard rock excavation contracts for their appropriateness to the soft ground tunnel work."

Jan 1, 2016

By A. W. Wensel

The adsorption behavior of sodium oleate on brucite, Mg (OH)2, has been studied by Fourier transform infrared spectroscopy. Both internal reflection and diffuse reflection (DRIFT) methods were used to characterize the adsorbed oleate on brucite. DRIFT measurements were shown to be quantitative, and an equilibrium adsorption isotherm was obtained. The conformational behavior of the adsorbed oleate was investigated as a function of adsorption density. It was found that at sub-monolayer coverage the alkyl chains of the adsorbed oleate had more ?gauche? character than at multi-layer coverages. Also, DRIFT spectra revealed that the adsorbed species were magnesium dioleate. For internal reflection measurements single crystals of MgO were hydrolyzed to form a thin Mg (OH)2 layer.

Jan 1, 1994

By H. J. Bogert

Shallow, gently dipping quartz veins at the Mineral Hill Mine are mined in room and pillar stopes. Ore zones are severely folded and fractured, thus actual pillar strength and physical properties of the rock mass deviate significantly from conventional laboratory tests and pillar theory. Laboratory specimens large enough to include pre-existing fractures proved to be representative of actual pillar strength. Further adjustment for specific pillars was based on RQD. Deformation and stress were measured in several pillars during pillar recovery. Stress data and finite element modeling were used to estimate absolute pillar stress at failure. The stress/strain relation provided an excellent indicator of pillar behavior. Good agreement between lab data and underground data was found.

Jan 1, 1995

By M. R. Smith

Barrick Goldstrike Inc.'s Betze/Post Open Pit is located at the north end of the Carlin Trend, in Eureka County, Nevada, U.S.A. (see location Map, Figure 1). About ten open pit gold mines exist on the trend, which strikes northwesterly, through the north end of Eureka County and into Elko County. The final Betze/Post Pit configuration is shown in Figure 2, Pit Configuration. The final pit will be about 2450m long by 1550m wide, elongate in a west-northwesterly direction. The pit straddles the Barrick/Newmont property boundary. The highest elevation of the pit perimeter is 1800m at the south wall, with the east end pit bottom elevation at 1200m.

Jan 1, 1993

By T. J. Malterer

Peat has unique physical, chemical, and biological properties. These include high porosity and water retention, high absorption and adsorption properties, high buffering capacity, and it is a rich medium for microorganism activity. Peat has traditionally been used for horticultural purposes. However, in recent years, peat is increasingly being used for waste treatment purposes. This paper reviews North American literature on the use of peat for waste treatment applications. The literature indicates promising use of peat in treating municipal and on-site effluent, removal of low concentrations of heavy metals from wastewaters, and adsorption of liquid and gaseous hydrocarbon pollutants.

Jan 1, 1995

By A Pettersson

LKAB owns and operates two of the largest underground mines in the world in Northern Sweden. In Malmberget, with a production capacity of about 30,000 t/day of iron ore, the current main 815 m haulage level is rapidly approaching the end of Its life and plans are being made for its replacement on the 1000 m level. Due to the separation of the orebodies, trucks have been chosen for transporting the ore from the orepasses to the crushers. The trucks currently in use have a capacity of 120 tons. To increase the efficiency of the loaded haul, the new main level will have a favorable slope from the drawpoint locations to the crushers. From the new level the crushed ore will be transported by conveyor to the 815 m level for hoisting to the surface. The paper discusses the planned mining and transportation system.

Jan 1, 1998

By J. A. Lombardi

Innovative hard rock narrow-vein, longwall, and stope leach mining systems concepts are described and evaluated economically. The principal tool proposed for use in these systems for both mine development and production is the U.S. Bureau of Mines radial-axial splitter. The mining systems concepts are prefeasibility level costed and projected to be cost competitive for steeply dipping veins, 0.6-1.2 m wide, for horizontal tabular ores 2 m -5 m thick, and for leachable ores with greater than a 1.7:1 stripping ratio. In all of the systems the orebody, less swell, is retained underground for use as backfill.

Jan 1, 1994

When I wrote the Railroad portion of "Mining Engineering" magazines 94 Powder River Basin (PRB) Coal Article I described to you some definite destinations the Railroads had in mind. As with many destinations, the ones I wrote of turned out to be merely stops on the way to places that we have yet to reach. Somewhere along the way we discovered that making it better is a continuous process not just something that you can do in phases I, II, III, & IV. We always knew this I suspect, but perhaps not at the awareness level that exists in RR environments in 1997. The purpose of this article is to update the 94 article, which I could do very quickly. Everything I told you we were going to do in 94 is done, end of story! But in addition to making it a very short article it would not be telling you the things RR has done beyond what we were planning in 94 and for the future.

Jan 1, 1998

By J. R. Allan

Loki Gold Corporation of Vancouver, B.C. is developing the Brewery Creek Mine, an open pit heap leach gold mine, 55 km East of Dawson City in Yukon, Canada. Mineable reserves are 17.1 million tonnes of ore grading 1.45 grams/tonne, containing 24.8 tonnes (797 000 oz) of gold. Ore processing will employ a cyanide heap leach using run of mine ore. Permitting this mine has drawn significant attention because the heap leach technology, while proven in other jurisdictions, has not been used in Yukon. Engineering design of the heap leach was similar to that for heaps in more temperate climates, with the added issues of permafrost and cold weather operations. Solution balance with seasonal placement of ore and year -round leaching requires very large pond capacity for spring thaw conditions.

Jan 1, 1996