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An open pit production planning method for stage mining is presented in this paper. The method brings solutions to the four most important parameters in stage mining : 1) the number of stages, 2) the size and geometry of each stage pit, 3) the mining sequence of the benches in the stage pits, and 4) the time of transition from one stage to the next. The method can also simultaneously optimize the ultimate pit, mine life, and production rate in each stage.

Jan 1, 1996

By Z. Yu

Dewatering of a -0.5 mm fine coal has been studied extensively. Deep cleaning requires however fine grinding, and dewatering of such ultrafine products presents a great challenge. Several coal samples finely ground and characterized by different wettabilities have b.een used in the filtration tests. Vacuum and press filters have been employed. In this paper only the results obtained with different flocculants (totally hydrophobic. semi-hydrophobic and hydrophilic polymers) are included. The results reveal the effect of coal surface properties and flocculant type on filtration of ultrafine coal.

Jan 1, 1994

By Judson G. Brown

In order to filter small amounts of fine slimy solids the reversible cake-filtration process was developed. The filterable solids contents lion in feeds can range from less than 1 ppm up to about 5%. The relative advantages of this process, are usually the greatest in the range of 0.05% to 1.0% filterable solids. Filterable solids that average in particle size about 20 microns& are non-compressible are very easy for this filtration process. Some feeds have been all sub-micron in particle size. A 1/8 inch thick cake is considered to be very thick. The usual cake is between 13/2 and 1/16 inch thick. A new line of injection molded plastic filter plates were developed for use with the reversible cake filtration process. The first commercial sized installation of this system was made 3 years ago in the Wakefield Y.M.C.A. swimming pool. Over 70 filters ranging in size from one plate to 63 plates have been produced. In addition to the process advantages there are the low cost and corrosion resistance advantages of the plastic plates.

Jan 1, 1962

Optimal gold recoveries largely depend on efficient liberation of the gold or gold-bearing minerals as well as on maximum access for the lixiviant. Thus, crushing and grinding may become the most costly part of gold ore processing. It may, in fact, represent 50% to 70% of a plant's operating costs (Michaelis, 1989). The increasing significance of refractory gold will require even more cost-efficient comminution of ultrafine sulfides and/or native gold. Transitional ore zones with semi refractory gold may respond to direct leaching if better particle fracturing is being achieved (Baum, 1991, 1993a). Many oxide ores have been left in the ground because they were unsuitable for heap leaching since conventional comminution could not facilitate economic gold extraction. Also, the costs of conventional bal1 mill operations did not permit the recovery of gold from many ultrafine, low-grade refractory ores. As shown by Marsden et al. (1993), the trend to treat ores with progressively lower grades will involve power-and leach-efficient grinding applications. Our current laboratory work shows that high-pressure grinding roll (HPGR) Polycom grinding may enable many mining companies to add large amounts of these "non-leachable" ores to their current heap or mill leach feeds. This finding may dramatically change the economics of many oxide gold ore operations and may add significant reserves to ores amenable to direct cyanidation.

Jan 1, 1994

By Juan Ares, Enrique Fernández, Alejandro Sanz, Francisco González

"INTRODUCTION Crossrail is a subsidiary company of Transport for London created for the construction of a new transverse train line 118 km long between Maidenhead and Heathrow in the West, and Shenfield and Abbey Wood in the East, including 21 km underground below London. Crossrail C305 Eastern Running Tunnels project is the biggest contract within Crossrail Project and involved boring 11.8 km of twin tunnels through London’s city center. Crossrail C305 Project interfaced with different contracts along its alignment and therefore logistics and solutions had to be developed to minimize disruptions or interferences with other contractors and the neighborhood. The paper describes this innovative approach. C305 CONTRACT APPROACH C305 contract was split into three drives, to be excavated by four EPB TBMs 7.1m diameter, as shown in Figure 1. •,Drive Y: 8.2km long between Limmo Peninsula and Farringdon Station in the city center •,Drive Z: 2.7km long between Pudding Mill Lane and Stepney Green Junction •,Drive G: 0.9km long between Limmo Peninsula and Victoria Dock Portal in the East. Crossrail C305 Project scope of works included the excavation of TBM tunnels and shafts at Limmo Peninsula and Stepney Green (including 17m span turnout caverns), along with the requirement to traverse station and shaft structures of other Crossrail contracts. Limmo Peninsula Site was a strategic element as it was the only access point on the tunnel alignment with sufficient available area at the surface for tunnelling logistics and also connected to the Lea River, tributary of the River Thames which facilitated marine operations for segment supply and muck removal. These were the reasons for operating Drive Y & Drive G TBMs from that location. Drive Z TBMs were originally planned to be launched from Stepney Green to Pudding Mill Lane, supplying the TBMs during Drive Z excavation from Limmo Peninsula site through the excavated section of Drive Y between Limmo and Stepney Green. During the early stages of the project, a value engineering proposal with a new tunneling strategy was agreed wherein the Pudding Mill Lane contractor would provide space for TBM assembly and operation in their portal, allowing for reversing Drive Z excavation and launching the two TBMs from Pudding Mill Lane. This optimization reduced some of the shaft requirements at Stepney Green which were contingent upon critical enabling works and provided program certainty and cost savings for the full Crossrail Project. It allowed for the reuse of both the Drive Z TBMs for Drive G excavation from Limmo to Victoria Dock Portal thereby saving on the procurement of two TBMs, in addition to easier logistics for both Drives Y&Z, therefore de-risking the TBM excavation process and the C305 Project program completion."

Jan 1, 2016

By J. Herhold, S. Plaum

"Increasing worldwide energy demands, coupled with desires for cleaner energy, have led to greater research of renewable energies. Strongly weather-dependent energy sources, e.g. solar and wind energy, are unable to provide a constant control energy to withstand the fluctuation of the extensive power systems during peak hours. The pump storage plant Nant de Drance in Switzerland will not only have the capacity of a nuclear power plant, producing 900 MW, but will also combine the environmental aspect and the demand for controlled energy. Nant de Drance is one of the pioneer projects for upcoming energy challenges and serves as a model for future pump storage plants. This paper focuses on the planning process and the project execution of interdisciplinary large-scale projects such as Nant de Drance, including project related data handling, communication systems and project handling skills. Furthermore, the paper discusses mining excavation in the context of large scale projects and their regional environmental challenges, e.g. high alpine rock mass on the site of Nant de Drance. PROJECT BACKGROUND Project Overview Nant de Drance is a 900 MW pump storage plant located in the Swiss Alps. To provide such a high energy storage, six turbines (reversible Francis type), each with a capacity of 150 MW, were installed. Due to the efficiency factor of 80% the pump storage plant is able to provide an energy production of 2500 GWh per annum. Construction of the pump storage plant, which has been selected as “Major Tunneling Project of the Year” in 2014 by NCE and ITA-AITES, will be completed over 10 years. Therefore, the project has been divided in six major phases outlined below: - Launch: 2008 - Access Gallery: 2010 – 2012 - Excavation KMA, KTR: 2011 – 2014 - Concreting KMA, KTR: 2014 – 2016 - Installation of HEM equipment: 2014 – 2018 - Tests & entry into service: 2017 – 2018 Figure 1 outlines the single process phases of the project. For the construction of the shafts, galleries and caverns, 1.7 million m³ of metamorphic rock with sedimentary origin (mica schist & paragneiss of the massif „Aiguilles Rouges“) were excavated. A tunnel network with a total length of 15 km was created. The machine cavern measures 194 m long, 32 m wide and 52 m tall."

Jan 1, 2016

By Q. Feng

Study has been carried out to apply fly ash as a high strength, water-resistant precast construction material through geopolymerization. Experiment results show that the working conditions such as water content, the concentration of NaOH, curing temperature and curing time, significantly affect the mechanical property of geopolymer matrix. Through optimization, an above 100 MPa compressive strength has been achieved with the geopolymerization products. Water soaking tests show that the geopolymerization product has a very high water resistance without losing noticeable compressive strength even after a one month soaking time. To elucidate the geopolymerization mechanism, microscopic techniques such as SEM/EDS and XRD are also applied to investigate the microstructure, the elemental and phase composition of geopolymerization products. The findings of the present work provide a novel method to apply fly ash as a high strength water-resistant precast construction material. INTRODUCTION Geopolymerization is a process of obtaining a polymeric structure from aluminosilicate by dissolving aluminosilicate sources in a strong alkali (NaOH) solution and condensation of free [SiO4] and [AlO4] tetrahedral units (Davidovits, 1985 and 1988; Duxson et al, 2005; Xu et al, 2000, 2002). After being cured at an elevated temperature for a specific time, the geopolymerization product shows a greatly increased compressive strength. Therefore, the product can be used as construction material such as bricks and road pavement. It provides a very promising method to apply aluminosilicate sources such as fly ash as a construction material for a sustainable development. Fly ash is a main industrial waste which needs to be carefully impounded because of its potential impact on environment. Many efforts have been tried to utilize fly ash as construction materials substituting Portland cement because of the following reasons. First, fly ash is a silica/alumina rich aluminosilicate source, which makes the specific material an ideal source for the geopolymerization process. Secondly, the particle size of fly ash is usually very small (< 50 microns) and it saves a lot of energy consumed during the production process of cement for grinding. Thirdly, fly ash is an ideal source for geopolymerization because it is reactive to alkali even at a mild temperature. In the past twenty years, many studies have been carried out on the geopolymerization of fly ash to a make construction material. However, there are some disadvantages associated with the conventional methods of treating fly ash (Palomo et al, 1999; Perera et al, 2007; Temuujin, et al, 2009; Hanjitsuwan et al, 2014). First, in most of the proposed geopolymerization methods, a salient amount of sodium silicate has to be added. It therefore makes it complex whether the achieved mechanical strength of geopolymerization products is due to a real geopolymerization process between fly ash and alkali or just largely the solidification of metal silicate in air at an elevated temperature. Secondly, the authors have noticed that when the geopolymerization product is soaked in water, the solution pH increases sharply and the products will lose its compressive strength gradually in water. Thirdly, the compressive strength of the geopolymerization product as reported is usually less than 50 MPa.

Jan 1, 2019

By S. Frimpong, D. Ali

For achieving bulk economic excavation, large dump trucks are being used in majority of the earth moving operations resulting in high impact shovel loading operations (HISLO) which exposes the operators to high levels of whole body vibrations (WBV). As the truck ages, hydro-pneumatic suspension struts loses their capability to effectively attenuate the vibration. A system is required to monitor and predict the performance of the suspension struts in real time. Machine learning and artificial intelligence (AI) has been applied for modeling and predicting the suspension system performance for lighter/smaller vehicles. However, no work has been done to implement machine learning or AI for modelling and predicting the performance of hydro-pneumatic struts in large dump trucks. Therefore, current work is going to be a pioneering effort towards developing machine learning and AI models for solving this problem. Support vector machine (SVM) and regularized dual non-linear regression has been implemented in order to achieve the goal. 3D virtual simulator for CAT793D was used to conduct experiments in MSC.ADMAS environment. The two main recorded outputs were the RMS accelerations in the vertical and horizontal directions at the operator seat for characterizing the performance of the suspension system. During the development and the training of the models, eighty percent (80%) of the total experimental data was used and the remaining 20% was used during the testing and validation of the developed models. SVM model showed the desired accuracy in terms of hydro-pneumatic suspension system performance prediction for large dump trucks. These models can be implemented in the dump truck controller which can then be used to monitor the performance of the suspension system in real-time, and with that proper maintenance and/or replacement can be scheduled by the maintenance personnel. Workplace safety, operator’s health and the overall system efficiency can be greatly improved with an implementation of such an intelligent system. INTRODUCTION Large capacity dump trucks are being employed in any earth moving operation throughout the world for achieving bulk economic excavation [1, 2]. A large dynamic impact force is produced with large capacity shovels dumping material weighing 100 tons or more in to the dump truck under gravity. This dynamic impact force generates high frequency shockwaves which travels throug0068 the truck body, chassis and reaches the operator’s cabin and thus exposes the operator to severe levels of whole body vibrations (WBV). Recommended safe limits have been listed by the International Standards Organization (ISO) in sections 1, 2, 4 and 5 of ISO 2631 (1997, 2003, 2001 and 2004). An operator can got through a long term back, shoulders, arms and neck disability and disorders if exposed to the WBV levels beyond those limits. The dynamic impact force generated as a result of the high impact shovel loading operations (HISLO) was modelled by Ali and Frimpong [2]. Furthermore, the complete methodology for optimizing the dumping process and reducing the impact force has been provided by Ali and Frimpong [1]. The vibration attenuation system present in the dump truck requires improvement in addition to the dumping process optimization. The vibration attenuation system in the dump truck commonly consists of hydro-pneumatic suspension struts. As the dump truck ages, its suspension system deteriorates and therefore loses its capability to effectively attenuate the shockwaves and the resulting vibrations produced by the dumping process. The deterioration tales place due to the contamination of the hydraulic oil or oil and nitrogen mixing or due to the gas accumulator diaphragm rupturing. The monitoring of the output vibration levels can be used to evaluate the effectiveness of any suspension system. With the dump truck suspension system, the vibration levels at the operator’s seat can be used for the evaluation of the effectiven

Jan 1, 2019

By L. M. English

In the past 30 years, the research arena has changed significantly in all fields, mining included. The relative representation of the topics of research, how the research is performed, and who has performed the research have all changed significantly over these decades. Although there are a lot of subjective ideas concerning these changes, and there is a fair amount of anecdotal "analysis," there has been no actual study of these trends to verify the facts. The period studied is divided into six five-year periods for the purposes of comparison. Some of the trends analyzed are as follows: ? Co-authorship ? Research areas ? Research sponsors ? Cooperative efforts

Jan 1, 1995

By Verya Nasri, James Sullivan, Alex Varas

"INTRODUCTION Many major cities in the United States have a combined storm water and sanitary sewer network. Regular rainfall overwhelms the system capacity and results in millions of cubic meters of untreated sewage being dumped into local waterways. One legally mandated solution includes several kilometers of large diameter shallow or deep rock or soil tunnels, a pump station as well as associated collection sewers, diversion structures and drop shafts. In this paper, the basis for design of different system elements including the drop shafts and pump station is explained in detail. Common construction methods used for different type of shafts including tangential vortex and baffle plunge, and also pump station alternatives comprising cavern or various shaft configurations are discussed. DIFFERENT TYPES OF PUMP STATIONS The dewatering pump station serves as the heart of any deep CSO tunnel system and is critical to the goal of reducing CSOs by providing a controlled release of the stored tunnel volume to the wastewater treatment plant. As the major mechanical component of the project, the station will require the greatest attention by operations and maintenance staff. Designing a durable and easily operated pump station requires addressing some major challenges, including the following: • Longevity – equipment, materials of construction, and station environment • Controlling odors • Safety for operators and maintenance personnel • Easy access to equipment • Protection from hydraulic surges Location. Owners face a fundamental decision relative to the location of the pump station, which will affect how these challenges are addressed. The pump station can be built within the tunnel launch shaft or within its own dedicated shaft. This decision is driven by cost and schedule. Use of the tunnel launch shaft may provide owners cost saving opportunities by not having to construct a separate pump station shaft. However, this will likely extend the pump station construction as much as two years until the tunneling has been completed. Furthermore, delays to the tunneling operation would delay the pump station construction work, potentially leading to delay claims. For this reason, it has been more common to utilize a separate pump station shaft on recent CSO tunnel projects (Nasri et al. 2015)."

Jan 1, 2016

By D. L. Monroe

Technical service is assuming an increasingly important role in the sale of asbestos fibre,, Manufacturers are examining raw materials more closely than ever before in order to, obtain the most efficient usage in their processes. Asbestos is one of the more difficult materials to evaluate and consequently has been are of the last to be subjected to evaluation. The main problem encountered in the evaluation of asbestos fibre is that minor differences in grade and texture are not shown up by chemical analysis, and are identified only by specialized physical analyses or actual production use. However, such minor differences become more critical as manufacturing processes are made more efficient, and many purchasing agents and plant chemists are applying a closer scrutiny to their supply of raw asbestos fibre. Many processes have been formulated around grades and qualities of asbestos fibre, which were standard some time ago, but which may now be subject to modification and improvement.

Jan 1, 1959

By D. K. Mynear, J. S. Gardner, S. Mittle, A. A. Campoli

West Virginia, although having adequate solar insolation, has witnessed very little actual solar development to date. The reasons for this lack of development are varied, but the primary obstacles to future development appear to be the absence of state-level policies and regulations promoting growth in the solar industry. West Virginia possesses large tracts of under-utilized land throughout the state created by previous mountaintop mining operations that could theoretically be re-purposed for solar farm development. Accomplishing this task will require not only revisions to the current legislation, but also acceptance by utility companies, landowners, and mining companies. Solar developers will need confidence that they can secure revenue from the electricity and Renewable Energy Certificates (RECs) generated by solar projects. Additionally, solar companies will need assurance they will be protected from any non-related environmental liabilities that could arise in the future. The primary avenue in bringing significant solar development to West Virginia will come through large corporate clients demanding or partnering with utility companies for incorporation of solar options into their energy portfolio to help meet established sustainability goals. This scenario has been witnessed in other states where a large client demands renewable options. Solar development could also represent a means through which mine operators might alleviate some of their reclamation and bonding obligations; where the landowner could supplement income from their underutilized land holdings; and where displaced miners could be repurposed in solar installation/maintenance jobs. Utilizing data from the West Virginia Permit Database, this report identifies several mine sites that hold potential for solar development in the future. INTRODUCTION The diversification of energy sources in the United States (US) has seen major shifts during the past decade resulting from: • A sudden abundance of low-cost natural gas becoming available through advanced horizontal drilling and hydraulic fracturing techniques. • Incentive-driven policies leading to new development in alternative energy. • The emergence of renewable energy sources, proliferated by state and federal level incentives and falling capital costs. Coal was once the primary low-cost fuel source for the generation of electricity in the US for most of the last century, providing approximately 50 percent of the total production capacity. However, within the past decade lower-cost natural gas has overtaken coal as the primary source of fuel used in electricity generation, and renewable sources have steadily grown to account for approximately 10 percent of the overall mix.

Jan 1, 2019

By L. Yuan, R. A. Thomas

"Atmospheric monitoring systems (AMS) have been widely used in underground coal mines in the U.S. for the detection of fire in the belt entry and monitoring of other ventilation-related parameters such as airflow velocity and methane concentration in specific mine locations. In addition to an AMS being able to detect a mine fire, the AMS data has the potential to provide fire characteristic information such as fire growth (heat release rate) and exact fire location. This information is critical in making decisions regarding fire-fighting strategies, underground personnel evacuation, and optimal escape routes. In this study, a methodology was developed to calculate the fire heat release rate using AMS sensor data for carbon monoxide (CO), carbon dioxide (CO2), and airflow velocity based on the theory of heat and species transfer in ventilation airflow. Full-scale mine fire experiments were then conducted in the Pittsburgh Mining Research Division (PMRD) Safety Research Coal Mine using an AMS with different fire sources. Sensor data collected from the experiments were used to calculate the heat release rates of the fires using this methodology. The calculated heat release rate was compared with the value determined from the mass loss rate of the combustible material using a digital load cell. The experimental results show that the heat release rate of a mine fire can be calculated using AMS sensor data with reasonable accuracy. INTRODUCTION Fires at different stages generate different gases and smoke toxicity hazards. When fires occur in underground mines, a significant amount of toxic gases and smoke enter the mine ventilation system and are carried throughout the mine ventilation network, increasing the hazard potential for personnel even if far away from the actual fire. Although fires that develop to the point of rapid flame spread pose imminent hazards, fires in their smoldering, pre-flaming stages can also contaminate the mine atmosphere with debilitating levels of smoke and toxic gases. The most important parameter for evaluating the fire hazard in mines is the heat release rate (HRR), which is directly related to the rate at which heat, smoke, and toxic gases are produced and transported by the ventilation system, and provides an indication of the time available for escape or firefighting [1]. The HRR is also an important input parameter to mine fire simulation models. Measuring the HRR of an actual fire can be a difficult task. Early experimental measurement of HRR focused on the heat output as represented by the temperature of the product gases. In ASTM E1321 (LIFT test), an array of thermocouples was positioned in a duct which captured all gaseous combustion products to measure their average temperature. This approach assumed the flow is adiabatic, which is never a reality. Significant progress on measuring HRR was made when Huggett showed that, for most common materials containing C, H, O, and N, the average heat release per unit mass of oxygen is 13.1 MJ/kg O2 [2]. Thus, the oxygen deficit is a measure of the HRR in the flow that the duct captures. This approach is termed oxygen consumption calorimetry (or the oxygen consumption method), and is widely used in the fire protection community."

Jan 1, 2017

By Henk L. C. Meuzelaar

Most of us are aware of the relationship between the golden-yellow resin spots on Upper Cretaceous Wasatch Plateau coals and fossil tree resins (?amber?). Nevertheless, confusion remains about the exact chemical composition and structure of commercial coal resin preparations as well as their observed heterogeneity. In order to arrive at a more detailed chemical description we need to distinguish between micropetrographic, organic geochemical and process technological definitions of coal resins, which may include substantial quantities of constituents unrelated to fossil tree resins. New information on composition and origin obtained by Curie-point pyrolysis/evaporation in combination with isobutane chemical ionization mass spectrometry, as presented in this paper, points to the presence of four more or less distinct resin components: (1) a sesquiterpenoid polymer; (2) sesqui-and triterpenoid monomers and dimers; (3) a suite of triterpenoid alcohols, ketones and acids; and (4) a series of increasingly aromatized hydrocarbons with naphthalene and picene type skeletons. Moreover, a strong similarity is found between the composition of recent Dammar resin and fossil Wasatch Plateau coal resins. Some of the technological implications of these findings and the consequent need for a more precise chemical definition and nomenclature are discussed.

Jan 1, 1990

By V. N. Kolesnikov

The Sikhote-Alin part of the Circum-Pacific Ore Belt is characterized by wide distribution of Sn, Pb, Zn, W; Au, Ag, and other mineralization. This mineralization is regionally associated with the Late Cretaceous-Tertiary East Sikhote-Alin volcanic belt where it overlaps the Taukha accretiollary-wedge terrane of the Early Cretaceous age. The Pb-Zn deposits of the Dalnegorsk ore district may be grouped into the skarn (about 80%) and vein types. The skarn deposits are of major commercial value. Their geological position is controlled by the carbonate units located within tectonic melange of the Taukha terrane. Some other lithological and tectonic factors also play a significant role ill distribution of the mineralization. The ore bodies are traced to the depth of 1000-1500 m below the surface, having a pipe-lens shape and vertical zonation. Major minerals of the ores are galena, sphalerite, pyrrhotine, chalkopyrite, hedenbergite, quartz, and calcite. The minor elements of the Pb-Zn mineralization are cadmium, silver, bismuth, and copper. The paper describes relationships between mineral suites and minor element contents in the ores, as well as their significance for processing the ores. The metallurgy applied allows high recovering of the major components (Pb -93.9%; Zn -91.4%). However the tails contain some minor components that may be of commercial interest.

Jan 1, 1998

By Henry P. Ehrlinger

These are exciting times for those of us involved in the discovery, development, beneficiation, sales and end uses of industrial minerals. The known sources of traditional raw materials are rapidly being consumed or covered up with highways and urban developments. We would never knowingly cover up a source of gold, silver, diamonds, or even base metals with a shopping center, but it has been difficult to justify not locating construction atop a limestone, granite, or sand dune deposit. During the last ten or so years most of the users of significant amounts of industrial minerals have established task forces made up of geologists, mining engineers, beneficiation experts, ceramic and refractory scientists, and senior members of their purchasing departments whose duty it is to determine where the raw materials for their particular finished products will come from now and farther down the road, like 20 years from now. Likewise, these same ceramic and refractory scientists are developing new materials which require a never ending change into different raw materials and the traditional materials must be refined by selective mining, exotic beneficiation practices and expensive but necessary post-beneficiation treatments to produce minerals for commercial use that were either theoretical minerals or at best showcase specimens when most of us here today were in school studiously acquiring a vocabulary which included Calcite, Magnesite, Dolomite , Feldspar, (Labradorite had the play of colors the prof could see but which I rarely focused on) Wollastonite, Celestite, Chromite, Olivine, Barite and Lepidolite to name a few.

Jan 1, 1976

By Grant Davis

An International Symposium on the Ecology and Revegetation of Drastically Disturbed Areas was held at the Pennsylvania State University in August 1969. Scientists from 13 foreign countries and 18 states in the United States attended this meeting, which focused on those areas disturbed by mining. The symposium enabled scientists from all over the world to get together for two weeks and discuss informally some of the knotty problems of reclaiming these disturbed areas. Trying to present the results of each of the 64 papers delivered at the symposium might be difficult. So, I will try to bring you up to date on the general status of research on the reclamation of surface-mined areas, particularly in revegetation and hydrology. I will also mention some research that is under way but was not presented at the symposium.

Jan 1, 1970

By Sheldon P. Wimpfen

Under the Wilderness Act of 1964 and the accompanying House Conference Report, the Geological Survey and Bureau of Mines are charged with the responsibility of making recurring mineral studies of wilderness and wilderness candidate areas in national forests within and proposed for the National Wilderness Preservation System. The Wilderness Act, a major shift from the multiple-use concept of national forests, identified for the first time the value of mineral resource information in decisions for single-use designation of public lands. This concept was further realized when the Secretary of the Interior in May 1974 recommended that mineral studies be made prior to wilderness recommendations for five large Interior-managed game ranges and the Glacier Bay National Monument aggregating 7.8 million acres. Presently, our studies have been completed on 126 wilderness and proposed wilderness areas totaling 15.4 million acres in the national forests. In 1973, 1 year in advance of the act&apos;s 10-year review deadline, we completed the 34 primitive areas, originally the only potential additions considered by the 1964 Act.

Jan 1, 1975

By L. Yuan, J. H. Rowland, R. A. Thomas

"Hydrogen (H2) gas released during battery charging can result in cross-interference for carbon monoxide (CO) sensors used for early fire detection and compromise the integrity of the mine atmospheric monitoring system (AMS). In this study, a series of laboratory-scale and full-scale experiments were conducted to evaluate the responses of different CO sensors to H2 gas. In the laboratory-scale experiments, constant H2 concentrations in the airflow, from 100 to 500 ppm, pass through sensors. While in the full-scale experiments, increasing H2 concentrations generated as a byproduct from charging the batteries at the battery charging station rise to the sensors under different ventilation scenarios. The H2 concentrations at the CO sensor location were measured using H2 sensors and were correlated with the CO sensor response. The effects of ventilation and sensor location on the CO sensors responses were also analyzed. The results of this study can help mining companies to select appropriate CO sensors and improve the deployment of these sensors to ensure the safeguard of underground miners. INTRODUCTION As many types of battery-powered mining equipment such as scoops and shield haulers are used in underground mining operations, charging stations are required to charge the equipment batteries. These batteries are of lead acid chemistry. A safety issue exists with the battery charging stations as all lead acid batteries produce flammable H2 gas during the normal charging process. Overcharging or excessive heat can quickly cause batteries to produce even more H2. If H2 is not appropriately diluted or dispersed, it builds up, and the risk of fire and explosion increases. Mine Safety and Health Administration (MSHA) regulation (30 CFR Part 75.340) requires that battery charging stations should be housed in noncombustible structures or be equipped with a fire suppression system. When a fire suppression system is used, the battery charging stations must be ventilated with intake air that is directed into a return air course or ventilated with intake air that is monitored for CO or smoke using an AMS. The monitoring of intake air ventilating battery charging stations should be done with sensors that are not affected by H2."

Jan 1, 2018

By Q. Xu

The adsorption behavior of gold in ammoniacal solutions on to activated carbon has been studied. The gold loading capacity of the activated carbon used in the system and the recovery efficiency by the adsorption were examined. The parameters affecting the adsorption of gold on to activated carbon included temperature, agitation speed, concentration of &apos;cation and anion as well as that of ammonia. It was found that the maximum gold loading on activated carbon used was about 10 kg of gold per ton of carbon. The recovery of gold by the adsorption from ammoniacal solutions was dependent upon the initial gold concentration in the solution. A recovery of 98% of gold was obtained on to the activated carbon under experimental conditions after 120 hour adsorption. It was also found that the initial adsorption rate was relatively fast compared to the whole period of the adsorption. The apparent activation energy for the adsorption was measured to be 15.8 kJ/mol. It was believed that the kinetics of gold adsorption on activated carbon was controlled by pore diffusion.

Jan 1, 1995