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By M. A. Reyes, L. Yan

Heat and humidity buildup within refuge alternatives (RAs) may expose occupants to physiological hazards such as heat stress. The Mine Safety and Health Administration (MSHA) regulations require RAs in underground coal mines to provide a life-sustaining environment for miners trapped underground when escape is impossible. RAs are required to sustain life for 96 h while maintaining an apparent temperature (AT) below 95 °F (35 °C). The National Institute for Occupational Safety and Health (NIOSH) tested a 10-person tent-type RA, a 23-person tent-type RA, and a 6-person metal-type RA in its underground coal mine facilities to investigate the thermal environment over a 96-h period. The test results showed that mine air and mine strata temperatures surrounding an RA occupied by simulated miners (SMs) increased over the 96-h test period. The test results suggest that RA manufacturers should consider this increase in temperatures when calculating and evaluating RA components during surface and laboratory tests. The findings can equip stakeholders with additional considerations for calculating the interior heat and humidity temperature profiles for occupied RAs not tested in situ

Nov 22, 2019

By Dean Workman

Located in downtown New York City, this project necessitated an innovative conveyor design for successful muck removal. This paper will discuss the technical challenges and engineering solutions of the muck transport system which consists of every commonly recognized version of a belt conveyor. The elaborate system includes a TBM conveyor integral to the back-up system, a wall-mounted extensible conveyor, a crown-mounted transfer conveyor, a floor-mounted fixed-length conveyor, a pocket-belt vertical conveyor, three cascading overland conveyors, and one radial stacker. The most challenging design element was an over-land conveyor featuring a box truss for muck transportation over Northern Boulevard while simultaneously going under the Queens Plaza railroad viaduct. An overview of the project is provided along with the following topics: developing final plans from the proposal concept, interfacing with existing works, communication with the joint venture, and complying with local regulations.

Jan 1, 2008

By D. Campos, J. M. Macedo, S. Chadwick

The incorporation of low cost technology transfer to increase the ability of locals to acquire and maintain long term employment are key ingredients for sustainable industrial development. Alcoa’s Alumar plant on the island of Sao Luis is the largest and most modern refinery/smelter complexes in northern Brazil. The plant has one of the most advanced Environmental, Health, and Safety management process in the aluminum industry. Technical assistance, training and financial support were made available to Alumar to address social sustainability issues. Through several programs led by employees on a voluntary basis and applying intensive and extensive training programs, Alumar has enabled local people to develop skills on agriculture and land management, wastes minimization, small business development and administration, all based on sustainable development and social responsibility concepts.

Jan 1, 2004

By G. Bierie

The conveying of bulk materials is prone to problems. These problems can reduce the capacity and efficiency of the plant, and even threaten the health and safety of the workforce. This presentation will look at new conveyor technologies systems, and how, used separately or in combination, they can improve material handling.

Jan 1, 2007

By G. Tiravanti

A recurrent concern in mining operations is how to deal with the large volumes of fresh water used which in turn generates large volumes of effluents that have to be treated. Water treatment can focus in one of two main strategies: treat the effluent as it is produced, or use a simulation tool to optimize water use in the process and reduce volume of effluents, contaminants concentrations, operational costs, and so on. This article shows a successful tool developed in Matlab-Simulink® that allows modelling a mining process and simulating potential improvements to evaluate the results. This tool has been proven in Cu-Mo operations and recently it has been used in poly-metallic operations. This article reviews the 4 Key Steps required to achieve our goals: a) Elaboration and verification of the mining Operation?s Block Diagram, based on a field survey; b)Model construction and input flows and qualities in selected streams; c)Model Validation and Simulation of new alternatives like recirculation, changes in reagents and dosage, partial treatment, flows merges/separation, and others; d)Development of the Optimal Solution which consists on determining the CAPEX and OPEX.

Feb 27, 2013

By A. Eftimie, M. Stanley

The World Bank Group (WBG) believes that extractive industries can make significant contribution to sustainable development and poverty reduction, providing that environmental, social, and corporate governance issues are properly managed. The WBG recognizes that stakeholders have legitimate concerns about the impact of extractive industries, and management proposals are built around the central theme that investments and policy advice in the extractive industries should lead to poverty reduction. To help governments create appropriate policy and regulatory frameworks, this paper focuses on the linkages between overarching policies and laws and the management / governance of extractive industries at the local communities. It encourages the use of new instruments designed to help ensure that local communities benefit from extractive industries.

Jan 1, 2005

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Li-rich red mud was leached using acetic acid to investigate the leaching behavior of lithium followed by neutralizing with hydrochloric or oxalic acid. By neutralizing red mud using diluted hydrochloric acid (0.01 mol/L), 58.04–60.27% of lithium was leached using 25% acetic acid at 95 °C for 60 min. In the meantime, more than 95% of sodium and 85% of calcium were also dissolved in the leachate solution. While oxalic acid (0.5 mol/L) was used to neutralize red mud prior to acetic acid leaching, lithium performed lower leaching efficiencies (42.41–46.88%) in comparison of using of hydrochloric acid–neutralized red mud. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the condition. In this study, 25% (v/v) of acetic acid, at 85 °C for 60 min, was demonstrated as optimum conditions for lithium extraction from oxalic acid–neutralized red mud using acetic acid. The results would be useful and of interest for lithium recovery and purification from red mud.

By Thom Seal, S. J. Jung

This paper will combine three SME annual meeting presentations on reducing gold inventory in cyanide heap leaching. Information on Part I – Side slope leaching (SME 2003), Part II – Determining the dry zones using geophysical resistivity (SME 2004), and Part III - Presents a new technology “Hydro-Jex”, to introduce the required lixiviants to the un-leach or under-leach zones in heaps (SME 2005). This paper will describe how Newmont Mining Corporation continues to improve the economics of the heap leaching process for precious metals recovery.

Jan 1, 2005

By A. Noble

The design of separation circuits can be a complex, labor-intensive and costly process. While the engineer?s experience along with extensive data sets and simulation are crucial tools for determining the final solution, a more fundamental approach is suitable to compare preliminary options and reduce the number of potential alternatives. In light of this need, the authors have developed the Circuit Analysis Reduction Tool (CART?). This software package relies on the fundamental principles of linear circuit analysis; however, the solution methodology has been streamlined to automatically incorporate stream splitting and unique separation performance for each unit. The resulting tool allows preliminary analysis of circuit designs without the need of detailed feed characterization. In addition to the basic analytical approach, this paper supports the veracity of the methodology with several simulated examples for various separation models.

Feb 27, 2013

By Georgy Cherkashov, Svetlana Babaeva, Tamara Stepanova, Firstova. Anna

Seafloor massive sulfides (SMS) study in the Russian Exploration Area at the northern equatorial Mid Atlantic Ridge began after signing the contract with International Seabed Authority in 2012. In order to evaluate the SMS resources in the course of exploration the major and rare metals with economic value should be determined. The evaluation is based on geochemistry and mineralogy and particularly on the type of rare metals occurrence in the SMS. As a case study research of the Semyenov cluster of SMS deposits have been conducted.

Sep 1, 2014

In recent years there have been significant advances in computing power and programming technology, enabling more complicated processes to be modelled in greater detail. This has led to increased understanding of these complex processes, including mineral processing circuits. JKSimMet was developed over the past 35 years, incorporating outcomes from various research projects conducted at the Julius Kruttschnitt Mineral Research Centre (JKMRC), part of the Sustainable Minerals Institute at The University of Queensland. It is a steady-state software program that allows the user to mass balance, model fit and simulate crushing, grinding and classification circuits. JKSimFloat has been developed over the past 20 years, incorporating outcomes from the JKMRC and other institutions around the world through the AMIRA International P9 project ? The Optimisation and Simulation of Mineral Processing Circuits. It is also a steady-state software program, similar to JKSimMet, but is focused on analysing flotation circuits. Both programs have been used in a wide variety of optimisation and design projects over many years. This paper provides an overview of both JKSimMet and JKSimFloat and examples of how both programs have been used to better understand, develop and optimise mineral processing circuits around the world.

Feb 27, 2013

By J. D. Doll

MSHA has promulgated a rule to limit the exposure of underground metal/nonmetal miners to diesel particulate matter (DPM). In May 2008, the final personal exposure limit will be lowered to 160 µg/m3 total carbon. To comply with this rule, mine operators are implementing a variety of control technologies. In this study two types of control technologies (ventilation and cabs) which are being implemented in limestone mines were investigated. Two stone mines in this study use large diameter propeller fans for main mine ventilation and direct the air to the faces using auxiliary fans, stoppings, and long pillars while bypassing the old mine workings. NIOSH measured for sub-micrometer elemental carbon (EC) using SKC DPM cassettes (analyzed using NIOSH 5040) and a near real time instrument. With the present ventilation and the number and type of vehicles used, the concentration of EC from DPM at the working areas was at or below 400 µg/m3 for both mines and about 166 µg/m3 and 251 µg/m3 at the returns. The real time data showed that the ventilation was reaching the working areas and effectively diluting the DPM. Environmental cabs were also used to reduce DPM exposures in three underground limestone mines. Using NIOSH method 5040 and near real time EC instrumentation, NIOSH sampled inside and outside of a loader cab at one of these limestone mines to determine the effectiveness of the cab. The cab was found to be over 90% effective in removing DPM as long as the cab system was properly maintained, and doors and windows were closed.

Jan 1, 2009

By Georgene Renner, William R. Yernberg, William Gleason

American Commercial (ACI) offers a selection of ground control solutions. Beginning with steel liner plates installed in the Gratiot Avenue sewer system in Detroit, MI 1920, ACI is one of the leading designers and manufacturers of underground steel supports in North America. ACI is also a leader in fire-proofing underground structures with its Promat Fire Protection Boards. The sandwich panels have been used in many new and retrofit tunnel and underground construction projects worldwide. Ease of installation and replacement, cost effectiveness and superior performance have made this product line the premier choice of owners and designers for structural protection, fire-life safety requirements and architectural finish needs.

Jan 1, 2007

By Steve Kral

The domestic mining industry may be in the doldrums but there appears to be hope, at least from a regulatory standpoint. At least one US senator believes that the events of Sept. 11, 2001 made many citizens see the need for the country to become more self-reliant on its growing energy needs. Even before that tragic day, however, the Bush administration was making a strong push to open up more public land for energy and natural resource development.

Jan 1, 2002

The trend for using larger equipment in open pit mining to achieve cost effectiveness raises the question about the optimum economic point of scale in the current world of globalization. The present paper treats this question through the prism of a new methodology of assessing the impact of the size of production equipment on the economic outcomes of coal mining ventures. The methodology incorporates a production scheduling optimization model that implements both principles of mine planning, coal quality optimization and waste deferment. The implementation of the waste deferment principle dealing with the spatial and time aspects of the mine sequence arrangement allows the adequate modeling of the optimality of production equipment scale through the use of mine investment parameters, such as, purchase and ownership costs and discounted cash flows analysis. A case study is provided to illustrate the applicability of the new methodology.

Jan 1, 2004

By William R. Yernberg

What a difference a year makes. One year ago, the iron mining industry and the steelmaking industry in the United States were in trouble. Many companies were in bankruptcy, and talk of plant and mine shutdowns was rampant. At that time, it seemed difficult, if not impossible, to remain competitive with imported steel. In addition, the World Trade Organization declared as illegal the tariffs placed on imported steel. And many questioned the viability of the ironmining and steel industry in the United States. At that time, global economic conditions were the main contributors to the industry’s problems. However, since last year’s meeting, changes in global economics have actually helped the steel industry in the United States. Heavy global demand for steel has caused raw-material shortages worldwide. Much of the increased demand is a result of the economic boom in China. In addition, because of a weak U.S. dollar and higher international freight rates, steel imports into the United States have been reduced to about 50 percent of recent levels. These factors have contributed to a rebirth of the U.S. iron mining and steel industries.

Jan 1, 2004

By Robert Labbe

The final tunnel lining for this project involved pumping vast quantities of concrete over large distances under the extremely busy streets of lower Manhattan. Approximately 68,000 cubic meters (89,000 cubic yards) were pumped from various locations over 152 meters (500 feet) below ground (Figure 1) to create nearly 14.5 kilometers (9 miles) of 3.05 meter (10 foot) diameter tunnel. Total distances pumped exceeded 1,645 meters (5,400 feet) horizontally after a vertical difference of over 152 meters (500 feet). The urban setting of the operation, coupled with the long distances over which concrete was pumped, created many problems which had to be dealt with along the way. A three-shift labor operation was implemented to allow sequential pouring of tunnel sections nearly every day. The fine tuning of the mix design was critical to make this operation successful.

Following a disaster in a mine, it is important to understand the state of the mine damage immediately with limited information. Computational fluid dynamics can be used to simulate and ascertain information about the state of ventilation controls inside a mine. This paper describes a simulation of tracer gas distribution in an experimental mine with the ventilation controls in various states. Tracer gas measurements were taken in the lab experimental apparatus, and used to validate the numerical model. The distribution of the tracer gas, together with the ventilation status, was analyzed to understand how the damage to the ventilation system related to the distribution of tracer gases. This study will be used in future research in real mine measurements to compare collected and simulated profiles and determine whether damage to the ventilation system has been incurred during an emergency situation, the nature of the damage and the general location of the damage.

Jan 1, 2011

By M. J. Miller, N. Ripepi, M. Karmis, J. M. Conrad

Unmineable coal seams present an opportunity to sequester carbon dioxide emissions from power plants, while enhancing the recovery of coalbed methane. Injected carbon dioxide is adsorbed and stored on the coal surface while releasing methane that can be commercially recovered. Carbon sequestration, therefore, allows the utilization of unexploited mineral resources while reducing “greenhouse” gas emissions. This paper presents the feasibility, efficiency and enhanced recovery potential of coalbed methane production using carbon dioxide sequestration in the Central Appalachian Basin. The focus of research is on geological characterization of unmineable coal seams in Central Appalachia and the corresponding carbon dioxide storage capacity. Virginia Tech and Marshall Miller & Associates, Inc. conducted this research under the Department of Energy’s Southeast Regional Carbon Sequestration Partnership program.

Jan 1, 2006

By Y. Boissonnas

INTRODUCTION, The transalpine rail routes in Switzerland are well over one hundred years old. As the established routes no longer meet the demands of the continually increasing volumes of rail traffic between north and south, two new routes through the Alps were planed. The old Gotthard rail line is in fact a mountain railway. The northern and the southern access ramps?with a maximum speed of 80 km/h and a maximum slope of 2.2%?reach the old Gotthard rail tunnel at an elevation of approximately 1,100 m above sea level. This is approximately 900 m higher than the city of Milan. In 1992, the Swiss electorate people voted with an overwhelming majority in favor of the project to build the new base routes through the Alps. The Swiss voted again in 1998 in favor of the financing proposal for the new infrastructure. Swiss Federal Railways together with the BLS Lötschbergbahn were commissioned for the realization and management of the Gotthard and Lötschberg routes. AlpTransit Gotthard Ltd., founded by Swiss Federal Railways, was given the task of managing the design and realization of the Gotthard route until the start of regular service. In the meantime the shorter Lötschberg Base Tunnel was open to traffic in 2007