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By J. D. Miller

On the basis of nonequilibrium zeta potential measurements by laser-Doppler electrophoresis, the sign of the surface charge of alkali halides in their saturated brines has been established. The results are generally as expected from simplified lattice ion hydration theory. This recent electrokinetic information coupled with the stability and prevalence of collector colloids in such soluble-salt flotation systems suggests that the selective flotation of alkali halides is due to the adsorption of oppositely charged collector colloids by heterocoagulation. Experimental flotation results confirm this surface-charge/collector-colloid adsorption model and are presented herein.

Jan 1, 1992

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 R. L. Miller

"Why should we care about diesel quality amidst the complexity of mining for minerals? Mining companies use a large amount of diesel fuel in their worldwide operations, both for moving ore from the mine to the processing mills or transportation hubs, and to generate power for onsite processing. This creates a large carbon footprint and poses both environmental risk with the production of emissions, and public perception of how those companies do their business as stewards of the environment while incurring a huge fuel expenditure. To improve diesel quality and create incremental value and greater environmental stewardship, the opportunity is broken down into several segments: 1. Mining industry diesel consumption 2. Fuel quality issues 3. Impacts on operations, economics, and emissions 4. Potential solutions 5. How improved fuel quality saves fuel expenditures 6. Economics of improved fuel quality 7. Recommended testing process 8. Fuel quality analysis checklist MINING INDUSTRY DIESEL CONSUMPTION The average grade of mined Australian ore bodies has halved, while the waste removed to access the minerals has more than doubled over the last 30 years, thus increasing energy consumption by 70%, (http://eex.gov.au/industry-sectors/mining/). Energy consumption and intensity in mining and mineral processing is rising at around 6% per annum. The mining industry is a huge consumer of diesel fuel worldwide, and the SRS Rocco Report of 4 August 2014 gives a better picture of recent trends. To better understand the reasons to reduce both fuel costs and consumption, we need to compare metrics on the amount of diesel consumed per each ounce of gold produced over the last decade. The rate of diesel consumption in gallons per each ounce of gold produced for the top five worldwide gold producers has doubled in the last 8 years from 12.7 gallons per ounce in 2005 to 25.8 in 2013 as shown in Figure 1 below.This is caused by 1) lower ore grades requiring more hauls to get same amount of finished gold product, and 2) haul trucks moving ore from deeper sources in open pit and underground mines. For one large multi-national gold mining company, the 2005 waste rock / production ratio was 52 metric tons/gold ounce; by 2013 that ratio had grown to 113 metric tons/gold ounce per the same SRSrocco 4 August 2014 report. Using the metrics above, the top 5 gold miners used over 591 million gallons of diesel fuel in 2013. The cost of diesel in dollars per ounce of gold has increased from $30.48 in 2005 to $101.14 in 2013, an annual appreciation of 16.2% as shown in Figure 2 below."

Jan 1, 2017

By W. Szymanski

The United States contains one of the world's largest reserves of uranium. Domestic production and exploration activities, however, have declined since the early 1980s due to weaker-than-expected growth in nuclear power demand and to foreign competition. The main result has been that more costly and less productive conventional mines and mills have closed. Meanwhile, industry productivity as measured by uranium output per employee has increased threefold since 1980. At the end of 1992, only six plants, all nonconventional, were operating in the United States. Due to cost considerations and increased environmental awareness, any additions to existing capacity are expected to be met through nonconventional in situ leach plants.

Jan 1, 1994

Power consumption of stirred media mills has been studied by an approach developed from work on stirred reactors. Relationships between torque required to rotate both disc and pin impellers immersed in dense particulate media as a function of speed, impeller and tank dimensions, and other relevant variables are evaluated. Data collected during numerous different experimental conditions are analyzed. The results can be summarized and presented in the form of characteristic plots, general equations and dimensionless group correlations involving power and modified Reynolds numbers. Special attention is directed towards the rheological properties of the media, which is considered as non-Newtonian liquids and hence, the equation of power law liquids is employed. Procedure for estimating parameters of effective viscosity and scale-up guidelines with respect to power consumption are put forward.

Jan 1, 1994

By I. Martinez-Dominguez

In September 1992, mining in Mexico was opened again to foreign investment by President Salinas-de Gortari, after thirty years of "Mexicanization" of mining industry which limited foreign participation up to a 49 % (or 34 % in case of national reserves) on a Mexican mining corporation. During said period mining in Mexico was controlled by four or five big mining companies and besides mining production was focused mainly on silver, lead, zinc, copper and fluorspar. Suddenly in middle of a big crisis on Mexican mining industry due to low prices of minerals in the world and also in a period on which it seems that mining industry in the United States and Canada has been condemned to die for environmental reasons, it appears a new Mexican Mining Law to permit foreigners to participate in mining in Mexico' trough Mexican mining corporations that they may control up to 100 %

Jan 1, 1994

By M. Polat

Variations in flotation rate by particle size and specific gravity have been investigated for three different bituminous coals. The flotation rates for various components were determined by separating the products of bulk flotation into size-specific gravity fractions. The effects of feed size and reagent addition on the flotation response of individual size-specific gravity fractions were evaluated.

Jan 1, 1994

By Rainer Antretter

"THE CHALLENGE The 14km long, Arlbergtunnel, closed for public traffic during summer 2015, receiving a comprehensive and substantial renovation from 2015 to 2017. The main works discussed here, carried out during 2015, comprise 37 drill and blast SEM/NATM emergency escape tunnels from road level to the ventilation duct plenum have to be constructed as well as eight additional lay-by niches and three transformer tunnels. This presentation comprises the construction ventilation design, designed according to national regulations, suitable for 150 employees working 24/7 simultaneously at more than 40 single working sites lined up along the tunnel. The ventilation-system chosen was utilising two existing shafts for intake/discharge and a cross passage to surface, to handle a total fan power of 1.600kW. DESCRIPTION OF RENOVATION WORKS Linking Tyrol and Vorarlberg, two Federal States of Austria, the Arlbergtunnel is a single tube two-way road tunnel with vent duct plenum, constructed in the mid-1970s. According to latest EU legislation, additional escape exits have become obligatory. The existing seven cross passage links to the adjacent Arlberg Railway Tunnel, with average spacing of about 1.500m constructed in 2007, an additional upgrade to shorter escape spaces of approx. 400m was now required to comply with the updated legislation. Additional transformer tunnels, lay-by niches and small niches for emergency maintenance use, cleaning and other purposes, as well as a the installation of a new fire main in the invert, coupled with the simultaneous replacement of virtually the entire power and signaling cables, generated several dozen small and large single sites distributed along the 14km of tunnel.Purpose of the 37 walkable emergency escape tunnels is to reach the “upper deck” of the Arlbergtunnel, the vent duct plenum. These have an 180deg curve in plan, inclined at 10% and approx. 60m (65yd) long tunnels, excavated using drill and blast method starting from road level and working upwards to the level of an “intermediate soffit”, the vent duct plenum in the crown of the tunnel. The vent duct plenum is separated into a fresh air part and an exhaust air part, shown in Figure 1. The escape tunnels end with a pressure door in the fresh air section of the ventilation duct plenum. From there illuminated signs show the shortest escape route to the safe area between the road tunnel and the railway tunnel, as shown in Figure 2."

Jan 1, 2016

By Raymond A. Bradbury

A significant news item appearing in a coal mining journal in November 1969 stated simply that a Caterpillar D-333-CNA engine had received Bureau of Mines Schedule 31 approval. This item occurring at the time a new mining property in Martin County of East Kentucky was being prospected and prepared for mining, resulted in the manage-ment of Martin County Coal Corporation asking the question, "Why not use diesel equipment in our new operation?" Martin County Coal Corporation is part of the A. T. Massey Coal Company, Incorporated organization. The property being developed is on a 17,500 acre leasehold obtained from Pocahontas Land Corporation and lies in the Wolf Creek area of Martin County. The Norfolk and Western Railway Company built a 24-mile railroad into this undeveloped section of Kentucky to tap a huge reserve of steam coal. Duke Power Company is the customer who will take all of the production from Martin County Coal Corporation mines which ultimately is projected to be 2,000,000 tons annually. Four coal seams, all above drainage, are included in the lease. The Middle Coalburg and Stockton are being deep mined now and it is in those mines that the diesel haulage equipment was introduced. This paper will endeavor to trace the steps loading to the introduction of the first diesel-powered Wagner Mining Equipment Company ScoopTram in a coal mine in America. It will further elaborate on the features which make this unit a very versatile and useful utility unit as well as the safety features which are incorporated in the machine. The success of this first unit led to the placing of

Jan 1, 1972

By J. Wiebmer

The two most important influencers of cost-per-ton in an underground mining machine are its productivity (tons/hour) and its availability-utilization (hours/year). Operating cost and initial price have far less impact. This paper reviews a cost-per-ton sensitivity analysis for underground mining equipment and discusses benchmarks for measuring its performance. The conclusion is that miner-supplier partnerships and the Information Age are the two most significant trends in cost-per-ton reduction.

Jan 1, 1997

By J. Platt

Debate over acid rain legislation has presented a moving target for coal and utility company planners attempting to figure out how legislation will affect their business environment. In spite of disagreement among experts, the prospect for continued change, and persistent --perhaps even growing --uncertainty, a great deal has been learned about coal market dynamics. This paper reviews progress and describes some of the major problems and controversies.

Jan 1, 1990

By A. E. Koski

This paper describes the implementation of specialized software in mine planning at the Cleveland-Cliffs' managed Empire Mine on Michigan's Marquette Iron Range. The application puts together years of mining experience on the eastern end of the Marquette Range beginning in the early 1960's. The Empire Mine, in its thirty-fifth year of production, uses the software to model a complex and highly variable low grade magnetite ore body, capturing the economics of mining and processing to the final product. With special attention given to geostatistical methods, the software is used for all geologic modeling, ore reserve estimation, ore control, pit design and short and long range planning.

Jan 1, 1999

By S. J. Jung

Determining the correct combination of mix components and water for high-density paste backfills with the transport and deposition properties necessary in a mining operation is a difficult task. Rheologic properties cannot be determined without conducting full-scale pumping tests, and data from existing tests are very limited. The following presents the findings of investigations undertaken to determine if paste backfill rheology can be determined using existing techniques and which mix and system variables have the greatest influence on transport pressure loss. Data from lab-oratory-scale pumping tests were used to produce a rheologic model of flow behavior for comparison, and a statistical analysis was conducted to determine the most significant factors affecting transport pressure loss.

Jan 1, 1994

By G. C. Kachel

Significant effort has been expended and considerable success has been realized m the application of instrumentation and automatic control equipment in the mining and ore processing industries. This effort has been applied principally to process equipment with the objective of increasing throughput, minimizing labor requirements and/or improving grade or product quality. Less spectacular, but quite rewarding has been the successful application of instrumentation and automatic control equipment to a wide variety of material handling equipments. This paper describes some of this work including: (1) automatic weighment of load-haul-dump units and trams underground; (2) automation of skip loading; (3) instrumentation applied in feeders and conveyors; (4) level measurement in bins, silos, vessels and sumps; (5) automatic blending of sized materials; (6) automatic loading of ships, trains and trucks; (7) automatic control of tailings disposal facilities

Jan 1, 1973

By R. G. Sinclair, E. Sangine, S. M. Fortier, J. Brainard, K. Stone

"The U.S. Geological Survey and Natural Resources Canada conducted a study on the net import reliance of each North American country, and the impact of North American trade on the net import reliance of 12 nonfuel mineral commodities that are associated with advanced technology products: cadmium, cobalt, gallium, germanium, graphite, indium, lithium, nickel, rare earth elements, selenium, silver and tellurium. The combined results for North America, using 2014 data, showed greatly reduced net import reliance for nearly all of the commodities evaluated, which is largely the result of pooling the resources of production and recovery in Canada and Mexico of materials that are consumed in the United States. This study highlights the mitigation of potential supply risk for critical materials that results from trade within the North American trade bloc. IntroductionMultiple metrics and definitions exist for what constitutes a critical material, but there is broad acknowledgment that a mineral commodity may be considered critical if, among other factors, its production is geographically concentrated, if it has few or no substitutes, or if the country of origin is politically unstable. Numerous governmental and independent researchers have proposed methods of investigating criticality, with differing priorities such as economic resilience or strategic military supplies (European Commission, 2014; Graedel et al., 2015; U.S. National Science and Technology Council Subcommittee on Critical and Strategic Mineral Supply Chains, 2016). While criticality really depends on who is asking the question, and despite the differing priorities, there are several commodities that are commonly found to be of concern. In particular, some critical or potentially critical materials are used increasingly in advanced technologies, or they have complicated supply chains because they are coproduced or are produced in controlled markets.Commodities for which imports are required to satisfy domestic demand are those for which the importing country is net import reliant. Net import reliance (NIR) in this study is calculated as the amount of imported material, including changes in stockpiles, minus exports and is expressed as a percentage of domestic consumption:"

Jan 7, 2018

By Ashish Ranjan Kumar, Barbara Arnold, Luis Sanchez Gonzalez

Mining operations adopt a variety of measures to combat dust underground. These include ventilation systems, water sprays, physical barriers, and personal protective equipment (PPE). Respirators are a class of PPE that can provide clean particulate- free air to the users. Powered Air-Purifying Respirators (PAPRs), used commonly in medical and other sectors, are not prevalent in the mining industry. PAPRs use P100 filters that have 99.97% dust capture efficiency. We present our results from computational fluid dynamics (CFD) simulations performed to understand the impact of a PAPR on airflow and dust particle concentration in the vicinity of a miner. These results show that donning PAPRs can lower the miners’ exposure to respirable coal dust in their workplace.

Feb 1, 2025

By Bruce D. Hebb, Shahin Shadlou

Fiber Reinforced Polymer (FRP) is an excellent material choice for a broad spectrum of corrosive fluids and, in many cases, offers the best value per dollar. FRP Flanges present the greatest design challenge of all standard piping components. The theory underlying the design of flanges is very complex. In addition, due to the nature of FRP material, proper fabrication of the flanges is as critical as the design. In this review, the challenges of making FRP flanges along with the design techniques and best practices of fabrication that will lead to a high-quality flange will be discussed.

Feb 1, 2024

By Francesco Chiappalone, Marco Invernizzi, Franco Gasperin, Brad Yoder, Fabrizio Fara

The Ship Canal Water Quality Project includes a 2.7-mile, 18-ft and 10-in internal-diameter tunnel that extends from Ballard to Wallingford, two popular neighborhoods in the West of Seattle. During the TBM Main drive a 12' × 12' boulder with variable strength up to 47,000psi was encountered resulting on signicant damages to the Cutter ead. The rst part of this paper describes the design and construction of an underground recess in front of the TBM to create a safe working environment for the TBM repairs. The second part describes an injection campaign performed to seal an unforeseen water inow appeared during the excavation of the 11 Avenue Diversion Structure.

Jun 23, 2024

By Reinhard Gertl, Soroush Dabiri, Juan-Carlos de Rueda

The Tunnel of Guillermo Gaviria Echeverri, spanning 6.05 miles, will be Latin America’s longest road tunnel, is currently under construction in Colombia’s Antioquia Department with a single bidirectional tube connected to a parallel rescue tube through multiple cross-passages. The study faces challenges in implementing the prescriptive semitransversal ventilation system due to design restrictions. Different ventilation concepts are eplored to nd the most suitable system for regular operation and re scenarios. A quantitative ris assessment evaluates each alternative system and identies the longitudinal ventilation system, accompanied by ris mitigation measures, as the safest choice, since it surpasses the prescribed semitransversal ventilation concept.

Jun 23, 2024

By Robert Bissonette, Samir Sbai

A critical component of implementing autonomous systems is the ability to use information from a robust sensory and information system to make sound, predictable, and repeatable decisions to assure safety. This means that any such system would need to evaluate what objects (people, equipment, boulders, etc.) of interest exist in that environment (with relevant data about identity, trajectory, characteristics, etc.), project a future continuum of those objects (including considerations for variabilities), and make control intervention choices to minimize risk due to exposures in the present operational area. The components of an overall system would include: a) sensor and data fusion, b) probability projection of future states, c) generation and evaluation of alternate futures, and d) implementation of best course of action to reduce risk. The National Institute for Occupational Safety and Health (NIOSH) Spokane Mining Research Division (SMRD) is studying this framework for applications for autonomous mining equipment. This paper focuses on using information from the sensor fusion engine to generate a continuous projection of future and alternate states (b and c above) incorporating the factors of confidence, accuracy, tolerance, and other variabilities. We refer to this as Machine Situational Awareness (MSA).

Jun 25, 2023