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By Arash Habibi, Anna Cable, David Loring, Aleksandar D. Bugarski, Logan Ingalls, Calvin Rutter

The results of diesel particulate matter (DPM) monitoring were used by the underground mining industry to mitigate adverse effects of exposure to DPM. NIOSH Method 5040, currently used for ambient and personal exposure monitoring, does not provide needed real-time information. The objective of this study is to develop a methodology for continuous monitoring of DPM concentrations in an underground environment, founded on the application of the Dekati electrical particle sensor (DePS). The DePS, which measures concentrations of submicron aerosol in real time using a diffusion-charging sensor, was evaluated by comparing the results of the concurrent measurements with reference methods at several locations downstream of the diesel-powered equipment. The DePS results were found to correlate well to those obtained by reference methods. However, it was found that dependence of the response on the physical and chemical properties of aerosols necessitates sitespecific correlation factors for the targeted matrices. The site-specific factors for number and mass of diesel aerosols were derived using the results of concurrent measurements with TSI NanoScan, FLIR Airtec, and carbon analyses performed on the concurrently collected filter samples. The results showed that methodology based on compensated DePS measurements would be suitable for continuous monitoring of DPM in underground mining operations.

Dec 1, 2022

By Enrique Farjeat P.

Mexico City's growth has encourage development of underworks to meet drainage and transport requirements. Deep Drainage System has been constructed through a complex tunnel network, 108 km in total, varying from 30 to 12 m in depth and 6.24 or 4.00 m in diameter. Wide range of stability conditions presented in soils has forced the use of several tunnelling methods, going from the manual procedure by the use of pneumatic tools, to slurry shields, or open face shields, with the aid of or without compressed air. For transport, subway tunnels have been excavated in very compact silty sands, 9.15 and 9.51 m in diameter, with the use of open shields one of which was designed by Mexican engineers as a prototype machine. This paper tries to describe evolution of tunnelling methods used in Mexico City during last 20 years.

Jan 1, 1991

By J. Ugarte-Núñez

Biodiversity assessments that are developed in different stages of a mining project, have different objectives that define the methodology to be used in each of these stages. In this way, we define two stages of a project: 1) the time at which assesses the state of biodiversity or biological components, before any intervention in the project area, previously defining the area of direct influence and indirect influence of the project for each biological group to be evaluated and 2) the time when certain groups or biological, are monitored during the developmental stages of the project with you to obtain information about the level impact they may have, for project activities. It discusses the methodological differences that must be used in both biodiversity assessments: to develop biological baselines and in those assessments aimed at monitoring different components of biodiversity.

Jan 1, 2011

By Jerome C. Neyer

Within most of Canada and the northern third of the United States, the soils overlying bedrock are of glacial origin. Tunnelling in glacial soils presents numerous challenges to the contractor, including abrupt changes in soil type, boulders and glacial erratics, water bearing fine sands and silts, toxic or explosive gases, and glacial till. This paper examines the available techniques for geotechnical exploration in glacial soils; the relationship between subsurface conditions predicted by various techniques and conditions actually encountered during tunnel construction; and potential improvements in the planning and implementation of geotechnical explorations. Case histories of geotechnical exploration and tunnel construction in glacial soils are also reviewed.

Jan 1, 1985

By D. E. Ranta, M. W. Springett

During the 1970's geostatisticians were often accused of not paying sufficient attention to geologic features in the computerized generation of ore reserves. Unfortunately this charge was all-too-often justified and the results of such studies tended to be oversimplified and failed to reveal the full potential of computerized reserve estimation and geostatistical methods. There were some notable exceptions to this trend. Techniques were described that paid a great deal of respect to the geologic characteristics peculiar to certain deposits (Rendu J-M, 1984; Barnes T. E., 1982). At Gold Fields several techniques have been developed for handling the geologic characteristics of orebodies for reserve estimation purposes. These have developed over time and the evolution of their adoption has been a reflection of our own learning experience from the practical application of computerised reserve estimation on many precious metals deposits.

Jan 1, 1992

By Remo Grandori, Fabrizio Antonini, Giorgio Dolcini

The paper describes the anticipated and the encountered geology, the TBM selection concepts and the machine special features, the tunnel sections, the achieved advance rates and the geological problems, the machine behaviour and the main setbacks caused by ground conditions the Authors also discuss the scopes for possible improvements to double telescopic shield machines, with special reference to their application under extreme geological conditions such as those that were met in the course of Los Rosales Tunnel excavation.

Jan 1, 1991

By J. W. Hawley, G. S. Austin, L. A. Brandvold, J. Renault

Soil next to a smelter abandoned about 100 years ago near Socorro, NM was found, by the US Environmental Protection Agency (EPA), to contain high Pb concentrations. Detailed characterization of the soil by the New Mexico Bureau of Mines and Mineral Resources (Bureau) shows that the highest Pb concentration is in the clay-size fraction, although this fraction accounts for only 1 to 3 wt % of the soil. The depth of contamination, determined in areas relatively undisturbed since the smelter was abandoned, is no more than 76 mm (3 in.). Because of the soil's alkalinity, the Pb mobility is dominated by the movement of Pb-bearing particles, as opposed to chemical transport in solution.

Jan 1, 1994

By Jeffrey J. Schwoebel, Jianliang Li, Daniel J. Brunner

A United Nations (UN) administered degasification technology transfer project, funded by the Global Environmental Fund (GEF) is underway at the Shihao Mine of the Songzao Coal Mining Ad- ministration in the province of Sichuan, Peoples Republic of China. This mine exploits multiple seams at depths ranging from 300 to 600 m below surface. In-seam boreholes and frequently spaced in-mine vertical boreholes, developed from underlying galleries constructed specifically for this purpose, currently degasify the seams in advance of mining at the Shihao Mine. Because of ventilation system constraints and the in-situ gas con- tent, longwall mining of the coals at this mine could not proceed without some form of pre-mining degasification. This paper presents a simulation based degasification plan of long, in-seam horizontal boreholes for the Shihao Mine. Simulations with a coalbed reservoir program assessed time dependent degasification characteristics of both vertical and in-seam horizontal boreholes. The simulations used input data from reservoir and desorption tests conducted at the mine site. The results produced system design nomograms to assist mine engineers in defining the appropriate borehole spacing necessary to degasify the seam in the time available for pre-mining drainage. The predicted effectiveness of the current vertical degasification scheme was compared with that for a horizontal borehole program and served as the basis for the recommended in-seam borehole configuration for the project at the Shihao Mine. The horizontal borehole degasification program requires substantially less gallery and borehole development than the present vertical degasification scheme.

Jan 1, 1997

By Jim Gebhardt

Douglas W. Fuerstenau (DWF) grew up on a farm and in several small communities in rural South Dakota during the depression years, where he learned the value of hard work. Working hard can produce results but being clever and hardworking will give you a bright future. In his later school years, Fuerstenau’s family moved to Rapid City where his intellectual curiosity and capacity helped him graduate with a B.S. in Metallurgical Engineering from the South Dakota School of Mines and Technology in 1949. His technical interests led to graduate studies and completion of a master’s degree from the Montana School of Mines in 1950 and Sc.D. degree from the Massachusetts Institute of Technology (MIT) in 1953.

By S. Mathur, Pradip

Polyacrylic acid (PAA) was evaluated as a selective flocculant for the dolomite-apatite system. PAA with a molecular weight (MW) of 4 million was found to flocculate both dolomite and apatite. However, the flocculation behaviors of dolomite and apatite were significantly different with 450,000 MW PAA, which was found to be the lowest molecular weight fraction capable of flocculation. In single-mineral tests with a dosage of 2 kg/t PAA, 90% of the dolomite and 35% of the apatite flocculated. Selectivity was achieved in mixed mineral tests. From a feed consisting of an 80:20 mixture of apatite and dolomite, respectively, a concentrate containing 90% apatite was obtained with a 70% recovery. The dolomite rejection was about 75%, which corresponds to a 2% MgO content in the concentrate.

Jan 1, 1997

By William H. Pomroy, Annie M. Carigiet

This U.S. Bureau of Mines report is an analysis of underground coal mine fire incidents occurring in the United States during the 15 years from 1978 through 1992. The fire data used in this analysis were obtained from Federal Mine Safety and Health Administration (MSHA) mine fire investigation reports. Fires were analyzed by year, state, coal bed thickness, mining method, evacuation measures taken, ignition source, burning substance, location, equipment involved, detection method, time of day, number of injuries and fatalities, and method of extinguishment. In all, 164 fires are reported, or an average of 10.8fires per year. The most common ignition source was electricity, the most common burning substance was coal, the most frequent fire location was the belt entry, belt conveyors were the most common equipment involved in fires, and water was the most common extinguishing agent.

Jan 1, 1995

By L. Bernoth, I. Firth, S. Rhodes, P. McAllister

As biotechnologies emerge from laboratories into main-stream application, the benefits they offer are judged against competing technologies and business criteria. Bioremediation technologies have passed this test and are now widely used for the remediation of contaminated soils and groundwaters. Bioremediation includes several distinct techniques that are used for the treatment of excavated soil and includes other techniques that are used for in situ applications. They play an important and growing role in the mining industry, for cost-effective waste management and site remediation. Most applications have been for petroleum contaminants, but advances continue to be made in the treatment of more difficult organic and inorganic species. This paper discusses the role of biotechnologies in remediation and pollution control from a mining-industry perspective. Several case studies are presented, including the land application of oily wastewater from maintenance workshops, the composting of hydrocarbon-contaminated soils and sludges, the bioventing of hydrocarbon solvents, the intrinsic bioremediation of diesel hydrocarbons, the biotreatment of cyanide in water from a gold mine, and the removal of manganese from acidic mine drainage.

Jan 1, 2000

By Liuhuai Ding

Background of Ocean Mining Research Inspired by the 1970?s deep seabed mining activities of other nations, China started ocean mining research work within the framework of the International Law of the Sea Treaty (UNCLOS) and the subsequent establishment of the International Seabed Authority in the 1990?s. This work has been carried out mainly with the cooperation of the Changsha Research Institute of Mining And Metallurgy. We have been committed to this work to fulfill our responsibilities and obligations as a Pioneer investor under UNCLOS and also to support the much needed development of deep-sea technology in China. Exciting recent advances by Nautilus Minerals in the development of seafloor massive sulfide deposit exploitation has led us to a new perspective of ocean mining and some re-evaluation of ocean mining economics. This has provided us with an opportunity to support more efforts in ocean mining research. We will not delay the development of our ocean mining system and corresponding technology, although commercial mining in the deep-sea area may not occur for many years.

Jan 1, 2008

By Didier Michel, Jean Frenay

Integration of amino acids in the thiosulfate gold leaching process has been noted in the literature. This paper presents a theoretical justification of this integration and demonstrates how amino acids can reduce the thiosulfate consumption of the process and contribute to the stabilization of the leaching system.

Jan 1, 1999

By R. L. Teseneer

Pyrite samples from twenty-one locations in the North Carolina Slate Belt were analyzed for cobalt, gold, mercury, and nickel by atomic absorption spectrophotometry. The geographic distribution of relatively high values of certain trace elements in pyrite suggests that, in addition to gold, cobalt and nickel metallogenetic provinces are possible in the slate belt. Northwest trends of province boundaries may be genetically related to subsurface features rather than to surface geology. Within province boundaries gold and nickel exploration programs should be concentrated in areas containing intermediate to mafic tuffs, while cobalt may be more concentrated in argillites and phyllites.

Jan 1, 1979

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

The rare earth element (REE) industry has sought to develop ore deposits where geologic processes have produced mineralized zones with commercially attractive concentrations. These deposits are extremely uncommon, particularly in the United States. Given the criticality of these materials and the need for a sustainable domestic supply, the current research seeks to leverage the generation and treatment of acid mine drainage (AMD) as an autogenous process that can lead to concentrated REE resources. 

By Robert A. Robinson, Steven R. Thompson, Harvey W. Parker

The Mt. Baker Ridge Tunnel, under construction in Seattle, will be the world's largest-diameter soil tunnel with an inside diameter of 19.2 m (63 ft) and an effective outside diameter of about 24.4 m (80 ft). The five-lane highway tunnel will be constructed using a "stacked-drift" scheme in which an articulated or "flexible" tunnel lining consisting of 24 concrete-filled drifts is constructed to form a horizontal compression ring followed by removal of the soil core. Geotechnical factors, including variable strength hard fissured soils, high horizontal stresses, potentially unstable sands, and prior slope instabilities, significantly influenced the innovative design and construction approach.

Jan 1, 1983

By Muhammad Kamran, NIAZ MUHAMMAD SHAHANI

This study elucidates a new idea to predict mine fire levels by employing several machine learning techniques. A total of 120 patterns of various mine fire influencing parameters, such as oxygen, nitrogen, carbon monoxide, and temperature, were compiled from the Adularya coal mine in Turkey. Techniques like t-distributed stochastic neighbor embedding (t-SNE) and k-means clustering were used to process the data, and support vector classification (SVC) was executed to predict various levels of the mine fire. The results revealed that the proposed model has higher credibility to predict the various levels of underground mine fires.

Feb 14, 2022

By Ellis G. Goree, George A. Simmons, Andrew B. Pervis

The pneumatic classifiers are widely used for fine dry powders separation These classifiers can be used for either the removal of fines from coarse feeds or the removal of coarse particles from ultrafine feed To optimize the operation of pneumatic classifiers, a thorough understanding of the impact of operational parameters on the efficiency of classification is essential This paper describes the design features and effects of operational parameters followed by illustrations of pneumatic classifiers usage in two case studies

Jan 1, 1983

By G. D. Hood, C. E. Jordan

The US Bureau of Mines investigated rapid froth flotation through more efficient bubble-particle collisions that improved the overall flotation kinetics. An in-line static mixer efficiently mixed the bubbles, water and ore, selectively attaching these bubbles to the hydrophobic mineral's surface. As the mixture entered the flotation chamber, the hydrophobic mineral was already attached to the bubbles and was quickly floated away from the remaining ore pulp. The rapid flotation system was evaluated for beneficiation with a western porphyry copper ore containing 0.67% copper and with a phosphate-bearing amine flotation tailings sample containing 9.5% P2O5 in a quartz matrix. Over 88% of the copper was recovered from the ore in a rougher concentrate containing 5.9% copper at a rate seven times, faster than conventional flotation. Sixty percent of the quartz in the phosphate-bearing sample was floated at a rate four times faster than conventional flotation. The unfloated product retained 80% of the phosphate in a 16.9% P2O5 concentrate.

Jan 1, 1994