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By C. H. Bucknam

Classical acid-base accounting using modified Sobek titration methods has resulted in interpretation of results for materials with neutralization potential (NP) less than 20 tons of CaCO3/1000 tons of material (2% CaCO3) as "uncertain" due to lack of sensitivity within that content range. Standardization of a "fizzless" acid neutralization potential (ANP) method was undertaken in the American Society for Testing and Materials (ASTM) International using two ranges of sulfuric acid additions based on reaction pH and carbonate carbon estimates rather than subjective fizz testing as well as hydrogen peroxide additions to correct for mineral acidity. The method is identified as the acid neutralization potential acidity (ANPA) titration method. During interlaboratory testing a positive bias was discovered within the "uncertain" range which was further investigated and resolved by increasing the test sample weight from one to five grams for samples needing improved accuracy in materials with ANP <2% CaCO3. Test results from the interlaboratory testing of the low range method is presented and compared with the results from the original ANPA method in the paper.

Feb 27, 2013

By Frederick C. Moore

This paper describes the original planning which actually resulted in the opening of a new aggregate plant located in central New York State. This plant, which is now named the Skaneateles Plant of The General Crushed Stone Company is unique in that the plant itself is a departure not only in design but in concept of operation from the normal aggregate plant the company has operated in the past. Whether or not the concepts which resulted in the Skaneateles Plant are economically feasible remain to be proven by the next few years of operation. By way of background data about our company which will help set the stage for this presentation, we currently operate seventeen stone quarries in the states of New York, Pennsylvania and Virginia. These quarries range in size from 200,000 tons per year to 1,500,000 tons per year with a total annual stone production of approximately 7,500,000 tons. We also produce about 1,250,000 tons of sand and gravel at six sand and gravel plants, 300,000 cubic yards of ready mix concrete, 1,500,000 tons of bituminous concrete, aglime and other minor construction materials. In many cases we are our own best customer consuming a large percentage of the total production of our own aggregates in our various ready mix and blacktop plants. Up to the concept of the Skaneateles Plant our operating facilities have been of the permanent type as opposed to the moveable or portable type plant. The steps involved in the case history of Skaneateles will begin with the basic economic requirements, market research, geologic surveys, land acquisition, zoning and financing and carry through to the final design and construction. We will attempt to show what some of the problems were, how we interpretted them and how we proceeded to solve them. The current results are apparent and can be analysed. The success of the total concepts of the Skaneateles Plant remains for future analysis.

Jan 1, 1968

If it had not been for the almost unbelievable adventures that came before and after, the last ten months of 19 15 would have been exciting enough for anyone. As it was they were a cheerful interlude. I spent most of the time on our Warren operations catching up on a lot of underground work and visiting Ajo every few weeks to see if my Chuquicamata visit might help solve the New Cornelia problem. While the difficulties were finally solved, at times they seemed almost hopeless. About all I could do to help was to make sure that the ore sent to the pilot plants represented the average ore that must be treated in the final 5000 tpd mill. Dr. Ricketts and John Greenway worked tirelessly with the best consulting advice they could obtain. Credit for the final success was due chiefly to their efforts. Since our old group had given up its "Merry Widow" home in Warren, a few of us got rooms in the company-built Cole Building over the Warren grocery store. This included Jim Lewis, Roy Mitchell, Steve Landon, Paul Stevens, and Hubert d&apos;Autremont who came from Duluth to join our legal staff. Later we rented a small house two blocks from the Calumet and Arizona office. With the now flourishing country club only a 10-min walk away, and an electric car running to it every half hour or so, we were able to give parties in return for the hospitality of our friends. One of the most pleasant episodes came by luck a few days after I got back from Chile. Chester Congdon, a leading director in Calumet and Arizona, with his wife and their daughters, Elizabeth and Helen, spent a couple of days at the Greenway house before making an auto- mobile trip across the desert from Tucson to Ajo. At the same time I arranged to examine the small but rich Bush and Baxter copper mine a few miles from Tucson. At a party in Warren we found we would all be staying at the Santa Rita Hotel in Tucson, and I took my South

Jan 1, 1976

By D. Anderson Willis, Alan A. Campoli, Douglas Mynear, Seth Mittle, J. Steven Gardner

"The diversification of energy sources in the United States has seen some 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 alternative energy sources proliferated as a result of state and federal level incentives and falling capital costs.Coal was once recognized as the primary low-cost fuel source for the generation of electricity in the United States for most of the last century, providing upward of 50 percent of the total generation capacity during much of that period. However, within the past decade, lower-cost natural gas has overtaken coal as the primary source of fuel used in electricity generation, and alternative sources have steadily grown to now account for approximately 10 percent of the overall mix.West Virginia and Kentucky have not experienced the full breadth of the fuel shift, and, as of 2016, still obtained approximately 80-90 percent of electric power generation from coal. However, as coal plants are retired, there has been a shift toward natural gas for new power plants constructed in the region. The economics of power generation (i.e., lowcost fuel source) has typically been the major factor in determining shifts from one fuel source or technology to another. However, governmental energy policies and incentives have more recently been used to promote the development of new alternative technologies such as wind and solar energy growth to diversify the energy mix. The implementation of these incentives has provided some needed traction and resulted in driving the cost of manufacturing and installation of these new wind and solar systems downward to be more cost competitive with conventional fossil-fueled power sources. Future shifts in the generation capacity by fuel type will also be inevitable and impossible to project accurately as policies change and innovative technologies evolve. Determining factors may include the expiration of current incentives, decreasing capital costs, future environmental regulations, evolution of energy storage systems, technical challenges associated with increasing intermittent sources of generation and the development of unforeseen technologies. West Virginia and Kentucky have been among the least solar friendly states, ranking 44th and 48th of the 50 states (Fig. 1 for WV). The ranking of other coal producing states are similarly low:• Ohio 20• Pennsylvania 21• Virginia 38• West Virginia 44• Wyoming 45• Kentucky 48• Alabama 50"

Jun 1, 2019

By A. Rajoria

A dynamic process model for predicting the fluidized bed roasting of copper concentrates with high arsenic content is presented in this work. Mass and energy balances were performed based on roasting mechanism derived from thermodynamic data of species. The reaction rate data, obtained from pilot plant studies on major reactions, were used in tuning the kinetic parameters of the model. DEAS, a dynamic simulation package, is used in setting up the fluidized bed roaster plant model. The effect of process parameters such as concentrate feed rate, concentrate composition, airflow and cooling water rate on the temperature and conversion of roasting reactions are analyzed. The plant model captures the highly transient conditions occurring during the plant start-up, shutdown and other process perturbations. The application of this model in constructing a virtual plant environment for validating the operating procedures and operator training is presented.

Feb 23, 2014

By Yongjun Peng, Yufan Mu

Pyrite depression in the flotation of copper ores is difficult due to the activation of Cu2+ ions on pyrite surface. In this study, the radical chain reaction involving the redox cycling of Cu(I/II) induced by sodium metabisulphite (MBS) was exploited to selectively depress the flotation of copper-activated pyrite at pH 8.0. Electrochemical measurements revealed that the presence of Cu2+ and O2 was essential to the formation of SO•− 5 through sulphite oxidation, the main entity to convert the activating species Cu(I)S on pyrite to Cu(II)-hydroxide/sulphate, causing deactivation of pyrite. The depression role ofMBS on pyrite flotation was closely associated with the type of grinding media which affected the electrochemical conditions of flotation. When forged steel was used as the grinding media, a high dosage of MBS was required to depress pyrite, but a low dosage of MBS could almost completely depressed pyrite when high chrome steel grinding media was used. This is because high chrome steel produced a stronger oxidation condition with a higher amount of Cu2+ and O2 which promoted the formation of SO•− 5

Jan 26, 2021

By R. Pazhianur

Cathodic Protection using impressed current was employed to reduce the wear of the mill wall during ball mill grinding. Wear rates were determined from weight-loss measurements made on four, I-inch diameter, mild steel coupons installed flush with the interior surface of the mill wall. Grinding tests were conducted on quartz, pyrite and quartz-pyrite mixtures at pH values of 4.6, 7.1 and 9.2. Cathodic protection was shown to reduce mill wear by 40-60010. An examination of the coupon surfaces using scanning electron microscopy showed that cathodic protection greatly reduced pitting corrosion. The presence of a sulfide mineral, such as pyrite, was found to increase the wear rate significantly, possibly due to galvanic interactions. It is also found that the wear rate is significantly higher than the sum of abrasive wear and the corrosive wear, due to a synergistic effect.

Jan 1, 1996

The Department of Health and Human Services (HHS), National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), with the assistance of cooperating underground mining operations and state agencies, has conducted research exploring devices and technologies that could be used to assist miners navigating through smoke and dust resulting from a fire or explosion. Recent events in mines confirm that smoke and dust can enter and contaminate mine escapeways creating an atmosphere with severely reduced visibility. This reduced visibility results in substantially increased escape times, possible disorientation or confusion, and increased stress levels, and may prevent evacuation altogether. Tools or devices that assist miners in navigating through smoke-filled areas void of lifelines could make the difference in successful escape from the mine. This paper presents the results of OMSHR research to identify and evaluate tools and devices that could provide meaningful information to evacuating miners in areas with limited visibility and without the benefit of a lifeline.

Jan 1, 2011

Collaboration between education providers is the key to long-term sustainability and improved quality in mining education. The mining industry is now, more than ever, an industry doing business on a global basis. Staff are recruited by global mining companies in many different countries and can find themselves deployed anywhere in the world. The mining engineer of tomorrow must be willing to take on this international challenge, and must be educated to a level where he or she has a comprehensive grounding in technical aspects of mining engineering, but also a well-founded appreciation of management, social, environmental and cultural issues that may be encountered around the world. In order to deliver such an education, academic providers must collaborate at both a national and international level. This paper provides an overview of progress that has been made in Australia through the national joint venture ? Min¬ing Education Australia (MEA). Supported by the mining industry in Australia, through the Minerals Council of Australia (MCA), MEA has been operational since 2007 and is seeing the development of a range of innovative courses and delivery methods, together with a high level of staff cooperation across the country. MEA has also commenced some international teaching initiatives that are seen as a catalyst for a far greater degree of international collaboration in the future. Such activity is not only to the benefit of the students who are taught by experts from around the world, but it also ensures that individual univer¬sity programs remain viable in terms of staffing numbers and financial performance. The paper also presents some statistics on recent upward trends in mining engineering student numbers from around the world, in response to the global shortage of mining engineers.

Jan 2, 2010

By Z. Konstantinovic, M. Ahrens

Due to the large installed electrical power and the large number of electric drives in minerals and mining plants power factor compensation and harmonic filtering has always been an important issue. For the design of harmonic filter and power factor compensation installations several approaches can be taken. The paper describes different concepts and their advantages and analyzes special requirements and design considerations for minerals and mining plants. It also highlights areas where problems can occur and which points need to be addressed carefully. Optimized designs and solutions are discussed in case studies and the resulting energy savings and benefits for the plant operation are shown.

Jan 1, 2007

This chapter contains the edited transcript of the "Gold Heap Leach Information Exchange" session that was held at the 1990 SME/AIME Annual Meeting in Salt Lake City, Utah. The exchange occurred on the afternoon of February 27, 1990. The session was intended to act as a forum for discussing some of the more prominent operating problems associated with heap leaching precious metals. The information exchange was very successful. The exchange consisted of several panelists introducing and discussing different topics, follow by a comment and question period. This transcript contains the panelists&apos; presentations as well as comments and questions from the floor and the panel. Extraneous comments and remarks have been edited out. Some wording has been changed for clarity, but the transcript is basically an accurate account of what was said. At the end of the transcript are two papers submitted as part of the panel discussion

Jan 1, 1990

By H. Verakis, M. A. Hockenberry, A. C. Smith, J. H. Rowland III

Four different types of fire suppression systems were evaluated in large-scale fire experiments to study the effect of air velocity on their effectiveness in extinguishing conveyor belt fires. The four different types of suppression system were water sprinkler, deluge-type water spray and two different dry chemical fire suppression systems. The large-scale fire tests were conducted with 1.8-m- (72-in.)-wide fire-resistant rubber belt that met the Mine Safety and Health Administration flame resistant requirement specified in Title 30, Code of Federal Regulations, Part 18, section 18.65 (also known as the 2G Flame Test). Each fire suppression system was tested at air velocities of 152 - 168 m (500–550 ft) per minute (mpm) and 411 - 457 mpm (1,350 - 1,500 fpm). Two tests were conducted at both air velocities for each fire suppression system. Both of the water-based fire suppression systems were able to suppress the fire to the point that a miner could extinguish it with a fire extinguisher. However, the amount of water needed to suppress the fire to the point where a miner could walk up to and extinguish any smoldering belting was greater than the current MSHA regulations required. MSHA regulations only require 10 minutes of water supply for a suppression system. In the test setup, neither of these systems would have suppressed the fire had the water been turned off to the system after 10 minutes. The dry chemical suppression systems produced mixed results. Dry chemical suppression system A did not suppress the conveyor belt fire at either air velocity. Dry chemical system B suppressed the fire at 152 mpm (500 fpm) air velocity, but produced mixed results at the higher air velocity. Details are presented on the large-scale fire test setup, arrangement of the fire suppression systems and conclusions regarding the effect of air velocity on fire suppression system design and performance.

Jan 1, 2010

By M. De Ladurantaye-Noël, M. Laliberte

Selenium is widely present in the environment at usually low concentration. It is mostly present in the environment at higher oxidation states, i.e., as selenites and selenates (+4 and +6 oxidation states respectively). It is rarely present as selenides (-2 oxidation state) and almost never found as the element (0 oxidation state). Selenites and selenates are generally soluble in water, as such they cannot easily be removed from water by precipitation. Selenites can form insoluble surface complexes with metal oxides such as ferric hydrous oxide and manganese hydroxide, and can therefore be removed that way. However, it is not so common to find selenites in natural environments as it will quickly oxidize to selenate in aerobic conditions. Elemental selenium can also be produced from selenites or selenates by using a reduction process; the end product is a colloid that can be destabilized to be removed from water using the right chemistry. Because of their toxicity, selenides need to be handled with care, and if present, it can form insoluble metal salts or, at low pH, be emitted as H2Se, a noxious and highly toxic gas. The most favorable selenium forms for its removal are therefore selenite and elemental selenium. Organo-selenium species play a crucial part in understanding selenium toxicity. There are a great number of these species. Basically, any organic species that contains sulfur has an equivalent that contains selenium. Of particular interest is the substitution of sulfur by selenium in the two sulfur-bearing amino acids, cysteine and methionine, resulting in selenocysteine and selenomethionine. Methylseleninic acid (CH3SeO2H) is another organo-selenium specie which has been detected in water treated by biological processes and which is biologically active.

Feb 1, 2023

By Y. Pan, V. V. S. Vytla, P. Tukkaraja, R. BHARGAVA, S. Jayaraman Sridharan

Panel caving is an underground bulk mining method that utilizes gravitational force for mining massive, steeply dipping, and deep-seated ore deposits at a lower operating cost. To control dust and gas emissions entering the production level during the extraction of ore from the draw points in a panel cave, relatively negative pressure is created in the cave by installing an exhaust fan in the exhaust drift located on top of the cave. Since caving is a dynamic process, the design of an effective ventilation system is a challenging task, and therefore, estimation of airflow resistance offered by the broken rock inside the cave is critical. The complex and dynamic nature of caving also makes it difficult to predict the airflow resistance by using traditional approaches. This study investigates the effect of changes in the bulk porosity of the broken rock on the cave airflow resistance using computational fluid dynamics (CFD) approach. The results show an inverse relationship between the cave airflow resistance and the bulk cave porosity. The pressure-quantity characteristic curves presented in this paper provide valuable information for sizing and operating an exhaust fan used for a mature panel cave ventilation.

May 17, 2022

By B. Samanta

This paper highlights the use of an innovative mine production scheduling scheme for grade-control planning tasks that take into consideration grade-model uncertainty. The scheduling exercise has been carried out with the help of a multiobjective genetic algorithm (MOGa) for the production scheduling operations. The underlying motive behind the use of MOGa has been the generation of a set of pareto optimal solutions to meet the goals of the target-grade specifications for the considered multiple grade attributes. Several new concepts related to MOGa formulation, in particular the mutation operation and the convergence criteria of this algorithm, are proposed in this paper. The modeling of grade uncertainty into the scheduling outputs has also been incorporated through a set of conditional simulated grade maps. The proposed scheme of production scheduling operations has been applied for the grade-control planning operations in an iron ore mine to meet the targeted grade specifications of iron, silica and alumina, and a risk analysis has been performed to this end.

Jan 1, 2013

By V. A. Leach, J. R. Johnson

The calculation of the dose to the bronchial epithelium, lungs and other body tissues from exposures to airborne radon and thoron daughters requires a knowledge of the pattern of deposition in the respiratory system and clearance from it. Exposure to radon or thoron daughters is measured in units of Working Level Months (WLM), which is independent of the aerosol particle size, the fraction of daughters that are attached to the aerosol and the degree of disequilibria between the daughters, and age and breathing rate of the subject. These factors will influence the deposition and clearance, and hence dose. It is therefore of interest to find the relationship between WLM and calculated dose as a function of aerosol size, unattached fraction, and disequilibria, and of age and breathing rate, and to define ranges for these parameters for which WLM is an acceptable measure of the risk. This presentation briefly reviews the two dosimetry models being considered by a current Nuclear Energy Agency (OECD) Working Group, and using these models, defines limits on parameters for which the WLM is applicable.

Jan 1, 1981

By Chas. F. Jackson

INTRODUCTION This paper is one of a series dealing with mining methods and costs, prepared and published under the sponsorship of the US Bureau of Mines (USBM) and made possible through the cooperation of many mining companies in the US and foreign countries. The data presented have been obtained from papers previously published by the Bureau dealing with indi¬vidual mines, from the technical press, and from infor¬mation furnished by the mining companies. DEFINITIONS Top Slicing The term top slicing is commonly applied to that method of mining in which the ore is extracted by a series of timbered slices, beginning at the capping; the slice is caved, bringing down the capping to the floor of the slice; the succeeding lower slices are mined up to the overlying mat or gob, consisting of an accumulation of timber from the upper slices and broken capping, which follows the mining progressively downward (Fig. 1). The term has also come to be applied to the mining of ore bodies only one slice thick, by a series of tim¬bered slices one beside the other. The timbers are blasted out, bringing the capping down to the floor, suc¬ceeding slices being driven alongside those already caved (Fig. 2). In USBM classifications of mining methods, top slic¬ing has been placed under the heading caved stopes. The method differs fundamentally, however, from the cav¬ing methods of mining in which the breaking of the ore itself is accomplished by caving action induced by undercutting. In top slicing the ore is broken by the ordinary methods of drilling and blasting, and only the capping is broken up by caving. Main Levels or Haulage Levels Main or haulage levels are the main extraction levels on which the ore is hauled to the shaft. These levels and the shaft constitute the preliminary development of the mine.

Jan 1, 1982

By D. R. Spears

As part of its mission to develop technology to assure a continuing supply of minerals, the US Bureau of Mines has investigated the flocculation of a Stillwater, MT, chromite ore. The ore was flocculated at different solids contents and at different stirring speeds to determine the importance and effect of hydrodynamic factors. In acidic and basic pH, the chromite ore was flocculated with high molecular weight polyacrylamides differing in the degree of hydrolysis. Polyacrylamides were found to bind to chromite ore particles through hydrogen bonding. The anionicity of the polymer and the pH affected the degree of polymer-particle interaction, which in turn affected polymer conformation at the surface. A polymer conformation with many loops and tails was used to explain high flocculation efficiency. It was found that such a conformation could compensate for poor hydrodynamic conditions.

Jan 1, 1992

By Derek Brennan, Donald Brennan

"The existing Rondout West Branch Tunnel (RWBT) is part of the Delaware Aqueduct which has been in service since 1944 and accounts for more than 50 percent of New York City’s water supply. In early 2015, the New York City Department of Environmental Protection contracted Kiewit-Shea Constructors, AJV (KSC) to construct the Rondout West Branch Bypass Tunnel project (Rondout) in order to mitigate the leakage of 132 million L/ day (35 million gpd) of water from two areas of the existing tunnel; the Roseton and Wawarsing areas.The scope of the Bypass Tunnel 2 project is separated into two distinct phases. Phase 1 consists of completing the shaft sinking to a depth of approximately 274 m (900 ft) at shaft 5B, 213 m (700 ft) at shaft 6B and the excavation of approximately 3,850 m (12,500 linear ft) of tunnel at a diameter of 6.6 m (21 ft 7 in). This phase also includes the installation of 2,804 m (9,200 linear ft) of 4.8 m (16 ft) diameter steel interliner pipe through the new bypass tunnel with cast-in–place concrete liner for a finished diameter of 4.2 m (14 ft). Access chambers at the top of shafts 5B and 6B will be constructed for access and housing of the mechanical and electrical equipment for supporting pumps and valves.Included in phase 2 is the additional excavation from shafts 5B and 6B to the RWBT, and the drainage tunnel to remove ground water infiltration from RWBT. This work will be completed during a scheduled shutdown of the RWBT and will include approximately 31 m (100 ft) of excavation of the two connection tunnels. Additionally, construction of the permanent plugs within the RWBT will be undertaken. Figure 2 shows the layout of the work.Access to the work through the deep shaft at site 5B was critical to the success of the project. The hoisting system needed to be multi-functional to handle the different types of construction from drill and shoot of the shaft, starter and tail tunnel, the assembly of the tunnel boring machine (TBM), the excavation of the TBM tunnel including the supply of the precast segmental liner, the grouting operations, the installation of the steel interliner pipe and the cast-in-place concrete as well as ingress and egress of personnel. The production of the TBM operations was critical to the schedule of the project. This required a quick cycle for muck haulage and supply of the precast segmental liner in order to keep pace with the excavation time of the TBM. For TBM assembly, components were limited to a maximum weight of 104 t (115 st) for a single lift. Various cranes were analyzed for hoisting, however, none would meet all of the citeria. Therefore, the project team selected a specialized hoisting system designed in house in conjunction with Timberland Equipment Ltd. that consisted of a total of 14 separate hoists and winches with a total of more than 2,833 kW (3,800 hp)."

Mar 1, 2019

Collaboration between education providers is the key to long-term sustainability and improved quality in mining education. The mining industry is now, more than ever, an industry doing business on a global basis. Staff are recruited by global mining companies in many different countries and can find themselves deployed anywhere in the world. The mining engineer of tomorrow must be willing to take on this international challenge, and must be educated to a level where he or she has a comprehensive grounding in technical aspects of mining engineering, but also a well-founded appreciation of management, social, environmental and cultural issues which may be encountered around the world. In order to deliver such an education, academic providers must collaborate at both a national and international level. This paper provides an overview of progress that has been made in Australia through the national joint venture ? Mining Education Australia (MEA). Supported by the mining industry in Australia, through the Minerals Council of Australia (MCA), MEA has now been operational since 2007 and is seeing the development of a range of innovative courses and delivery methods, together with a high level of staff co-operation across the country. MEA has also now commenced some international teaching initiatives which are seen as a catalyst for a far greater degree of international collaboration in the future. Such activity is not only to the benefit of the students who are taught by experts from around the world, but it also ensures that individual university programs remain viable in terms of staffing numbers and financial performance. The paper also presents some statistics on recent upward trends in mining engineering student numbers from around the world, in response to the global shortage of mining engineers.

Jan 1, 2009