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By Mark Kuchta, Hans Engberg

The Swedish mining company LKAB operates two of the largest underground mines in the world today that together produce around 35 Mton of iron ore per year. During the 1990s, the company embarked on a massive effort to computerize its mine planning system. The goal was to combine various mine planning operations including mine surveying, geologic modeling, mine layout, production planning, and production follow-up into one modular based integrated system. The system was built around a large Oracle database and the Microstation CAD system. This overall design strategy and the various system modules are described, and some experiences gained using the system are discussed.

Jan 1, 2002

By W. L. Price

Recent publication of United States Bureau of Mines figures showed that the sand and gravel (3) industry is the largest single mining industry in the United States in term of yearly tonnage produced. The yearly production of over 500,000,000 tons per year now exceed bituminous coal production. This disclosure caught unawares many observers who have not been following closely the rapid-growth of this phase of mining. Along with this steady growth in production, the sand and gravel industry has gone through an accelerated and varied program of beneficiation in a period of the last ten years.

Jan 1, 1958

When multiple mines operate in an area there are social, economic and environmental impacts which cumulate over space and time. These impacts require special attention. A collective approach is required to identify, assess and manage them. No assessment of sustainability of mining can be considered complete without accounting for cumulative impacts. This paper proposes a framework and typology to deal with cumulative impacts and tests this in a coal mining area in NSW Australia.

Jan 1, 2007

By J. M. Wempen

Booster fans, large underground fans, can increase the volumetric efficiency of ventilation systems by helping to balance the pressure and quantity distribution throughout a mine, reducing leakage and reducing the total power requirement. However, in ventilation systems that use booster fans there is a potential for system recirculation, the leakage of return air to intake air, and also for localized recirculation near the fan through the bulkhead and airlock doors. Air that is recirculated locally decreases the system efficiency because the quantity of air flow through the fan increases without increasing the airflow throughout the system. To understand the detailed flow characteristics of a ventilation system with a booster fan, two-dimensional computational fluid dynamics (CFD) models were developed using the software Ansys-FLUENT. Though two-dimensional models do not represent the full complexity of the flow dynamics, they do provide a good representation of the flow characteristics and they allow for a qualitative analysis of how the flow dynamics are affected by the system characteristics. The CFD models were used to evaluate how the number of booster fans, the booster fan placement, the location and geometry of the fan installation and the construction of the airlock system affect the flow characteristics and the localized efficiency of the ventilation system.

Feb 27, 2013

By W. E. Anderson

As part of a larger study to identify factors influencing the practical operating life of wire rope used on large draglines in surface coal mining, field trips to operating surface coal mines were made during late 1975. Wire rope performance information was obtained from personnel at thirteen mine sites west of the Appalachians. Seventeen pieces of equipment, utilizing buckets ranging from 30-to 220-cubic-yard capacity, were documented. We have judged that U.S. surface coal mining draglines, 30 yards and larger, can be represented as 120 machines having 60-cubic-yard buckets, moving 1.8 x 10 yards of overburden during 6,650 hours of productive availability per year. Based on our limited field study, we have calculated that downtime resulting from rope-related causes averages 105.6 hours per year for each (typical 60-yard) dragline. The total lost production from this source alone is thereby estimated at about 25 x 10 yards annually. Although study findings did not reveal anything about dragline rope life that wasn't known or practiced by one operator or another, most operators could expect improved rope life by periodic review of their practices and by adopting or adapting one or more life-improvement measures employed at other sites. Since rope productivity was found to vary by about five to one, among the sites studied, we believe considerably improved average performance is possible. As little as ten percent overall improvement would mean increased national productivity exceeding two million yards of solid overburden removal, and associated savings in rope costs alone of some two million dollars annually, not to mention any reduction of labor-related expenses. This report outlines preliminary findings which may prove useful to many operators in extending wire rope life, thereby lowering expenses and increasing surface coal mining productivity. Some of these modifications or adjustments in maintenance/operating practices would not require capital investment. We did not find anyone who had tried cost reductions by using presocketed dump

Jan 1, 1977

By Marina Carreiro-Silva, Cátia Cardoso, Bruce Shillito, Lisa Mevenkamp, Alastair Brown, Maria J. Bebianno, Juliette Ravaux, Inês Martins, Nélia C. Mestre, S. Sousa Vânia

Mineral extraction activities in the deep sea will expose the local fauna to potentially toxic compounds. However, very few data are currently available on the complex ecotoxicological risks to deep-sea fauna from the potential release of heavy metals, trace metals and Rare Earth Elements (REEs). Nonetheless, this is key information essential to support the regulation of industrial activities in the deep sea. One of the fundamental issues that the MIDAS project will address consists in exploring the concept of whether the existing toxicity test protocols and limits established in shallow-water species are applicable to deep-sea mining. We will detail the specific challenges to recommending exposure limits within the deep sea and show preliminary results of comparative toxicity tests in the shallow-water and in the deep-sea environment.

Sep 1, 2014

By J. M. Melluish

The metallurgical response of the Point Leamington deposit has been studied. Two series of bench tests were conducted and various ore samples and flotation products were examined using image analysis techniques. The majority of sphalerite and chalcopyrite grains in this texturally complex ore were found to be smaller than 10 micrometers. Copper recoveries were low with losses mainly as fine inclusions in pyrite. Sphalerite recoveries were somewhat better due to a generally coarser habit. Gold and silver recoveries were also low and only solid solution silver was identified in the ore. The deposit shows poor economic prospects unless additional tonnage of high grade zinc ore can be delineated.

Jan 1, 1989

By David S. Yang, Osamu Taki

The innovative Soil-Cement Mixing Wall Technique, developed independently in Japan, consists of mixing in-place soils with cement grout using multi-axis augers and mixing paddles to construct overlapping soil-cement columns. The applications of overlapped soil-cement columns include cutoff walls for groundwater control and structural diaphragm walls for excavation support. The special features of this technique include water tightness, versatile strength design, and efficient installation in subsurface materials varying from clayey soils to cobbles or soft rocks. Through the introduction of two recent subway projects in Japan, this paper presents the design parameters, construction procedure, quality control and performance of soil-cement wall for excavation support and groundwater control.

Jan 1, 1989

The 2012 North American Tunneling (NAT) conference is expected to attract more than 800 tunneling and underground construction professionals. But don?t let the North American part of the meeting?s title fool you. Many of the attendees will come from all over the world. The meeting is scheduled for June 24-27 at the JW Marriott Indianapolis Hotel in Indianapolis, IN. In addition to two and a half days of technical programming, the accompanying exhibit has attracted 116 exhibitors in 140 booths. And the conference will include short courses, a field trip and plenty of social activities that will give attendees the opportunity to catch up with each other.

Jan 1, 2012

By R. W. Hutson

One of the fundamental precepts of experimentation is the isolation of a single variable to quantify its individual effect. Unfortunately, the variability of natural rock joints has frustrated such isolation. This variability and the high cost of securing a large member of natural joints has lead to increasing experimental dependence on stage shearing, artificial tension fractures and/or model materials. The new apparatus described herein allows for the first time replication of real joints with field scale asperities. It employs a diamond band-saw blade with computer controlled feed table to cut joints with high precision. The feed system is capable of placement to tolerances similar to those of a high quality computer plotter. The accompanying software allows the table to cut any desired joint shape (repeating or non-repeating) within certain, over-all size limitations. Resulting joint surface dimensions and roughness as well as shear resistance indicates that the joint surfaces are reproduced with a precision similar to that possible for the control of other experimental variables such as normal and shear forces.

Jan 1, 1986

By J. Sammarco

Proper illumination is critical to a miner?s ability to detect hazards in underground mines. Moving hazards are often located in the miner?s peripheral field-of-view, while slip/trip/fall hazards are often located in the forward field-of-view. The objective of the research described in this paper was to determine if light-emitting diodes (LEDs) improve visual performance as compared to traditional incandescent (INC) cap lamps. The research presented focuses on comparative studies of a National Institute for Occupational Safety and Health (NIOSH) prototype LED, a commercial LED, and an INC camp lamp. Thirty subjects participated in these studies; ten subjects in each of the age groups: 18 to 25 years, 40 to 50 years, and 51+ years. Visual performance was quantified by the subjects? speed and accuracy in detecting hazards, while visual performance for disability glare was quantified by the use of contrast sensitivity tests. Results suggest that LEDs with a visible spectrum containing a higher concentration of the shorter wavelengths can enable visual performance improvements with respect to disability glare, the detection of moving hazards in the peripheral field-of-view, and the detection of floor hazards in the forward field-of-view. The NIOSH prototype LED cap lamp provided the best visual performance improvements for the older age groups in every test. Disclaimer: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By Dr. Richard F. Coon, James D. Mavis

Risks and abatements associated with preliminary reconnaissance, plugging and filling, and maintenance of perched mine water pool are examined. This case history showed that the initial appeal of portal plugging was replaced by concern over potential environmental hazards when details of implementation were investigated.

Jan 1, 1992

By Eugene M. Trisko

Presentation Overview State-Of-The-Art Scrub/Switch Analyses > Allegheny Power System > PSI Energy UMWA Phase I Coal Interests > 16 Phase I Scrub Plant Coal Profiles > Coal Price/Emission Allowance Interaction Southern Company Case Study > 2+ Million Ton Phase II Allowance Purchases > 10+ Million Ton Phase I Coal Switch > Georgia PSC Proposed Fuel Price Cap > Shift/Avoid Georgia Scub Costs Through System Allowance Purchases

Jan 1, 1993

By T. M. Yegulalp

A numerical model is being developed to assess the enhancement of permeability by improved fracture connectivity by micro-hydrofracturing. A generic two-dimensional percolation model has been developed to test the impact of various field conditions on permeability. Field data from Cyprus Minerals' Mineral Park Mine has been used to establish statistical properties of the observed fracture systems. Results of statistical anlyses of the field data and examples of the use of percolation model are presented.

Jan 1, 1995

The feasibility of exploiting a mineral deposit by developing a surface mine is closely related to the environmental protection and land reclamation costs. This issue has utmost importance for West Macedonia Lignite Centre (WMLC) of Greece, where there is still a lot of interest for opening of new mines and for further development of the existing open-pits. The decision-making process in these cases can be based on a decision tree that takes into consideration the various cost components of environmental management, the alternative solutions, the environmental permits and the cost reports of environmental management actions carried out so far. Moreover, the mine planning procedure is affected indirectly by numerous uncertain environmental and socioeconomic parameters, such as the delays caused by the bureaucratic procedures and the settlement of arguments in the Court.

Jan 1, 2006

By S. Holtermann

Through the process of Riverbank Filtration (RBF), the Louisville Water Company plans to obtain a higher quality source of water for their B.E. Payne Water Treatment Plant (WTP) by means of four collector wells located in the alluvial aquifer along the bank of the Ohio River. The collector wells are connected to a 2,850 L/s (65 mgd) pumping station by a 2,362 m (7,750 ft) long, 3 m (10 ft) finished diameter tunnel located in limestone and shale bedrock, which is approximately 45 m (150 ft) below the surface. High tunnel boring machine (TBM) production rates were achieved in this moderately weak bedrock; most of the tunnel only required support in the crown. An unanticipated water-bearing fault and unanticipated ground behavior proved challenging and required quick thinking to minimize impacts to construction. Tunneling conditions are discussed in detail, together with the methods used for overcoming the groundwater and ground behavior challenges. The tunnel is expected to be completed in April 2009.

By Richard L. Bullock

The hard rock mining industry has long envied its counterparts in underground mining of evaporites, coal and soft iron ore, who have made great strides in productivity using mechanical excavators. Continuous mining machines produce large tonnages in Canadian potash mines and in modern longwall coal mines. Hard rock is defined here as having an unconfined compressive strength (UCS) of more than 124 MPa (18,000 psi). Silica content, rock quality designation (RQD) and fractures affect the ability of mechanical tools to excavate rock, but the UCS is the main factor. Much research and development work has been devoted to continuous mechanical mining of hard rock, and the technology continues to improve. A few commercial applications have been reported. The development process has been slow and costly, but the outlook for the technology has never been more promising. The current state-of-the-art of continuous, mechanized underground mining technology is reviewed here, with examples of commercial applications that have been tried in recent years.

Jan 1, 1994

In spite of the tremendous amount of research conducted in the last few decades. no single blasting theory has been developed and accepted that adequately explains the mechanisms of rock breakage in all blasting conditions and material types. Given specific test environments, conditions and assumptions, individual researchers have contributed valuable information and insight as inputs into blasting theories, although a simple "plug-in" type formula for predicting optimum fragmentation, muck pile geometry and casting distance, is still largely unresolved. There is as yet, no consistent and widely applicable theory of blasting, but only a number of limited and disconnected theories; many of which are empirical in nature and based on ideal blasting conditions. Blasting theories have been formulated and based on pure speculation, years of blasting experience on a trial-and-error approach, laboratory testing, field investigation, and mathematical and physical models adapted from other disciplines of science.

Jan 1, 1988

By M. Fig, J. Brune, C. Strebinger, G. Bogin

"A fundamental understanding of flame propagation characteristics through and around obstacles is needed to accurately model methane driven longwall coal mine explosions originating or propagating in the gob. Experimental investigations of methane flames in horizontal cylindrical reactors with simulated gob (i.e. rock piles) were carried out alongside coupled Computational Fluid Dynamics (CFD) and combustion simulations. Stoichiometric methane-air mixtures were ignited in semi-open reactor vessels of 5cm, 9.5cm and 71cm diameter, all with a fixed length to diameter (L/D) ratio of 8.6. This was done both with empty reactors and also with a rock pile placed at the open end of the reactor. The rock pile length to reactor length ratio was fixed at 0.3, and the rock pile height to reactor diameter ratio was fixed at 0.33 for all reactors. The smaller two reactor experiments were modeled with ANSYS Fluent in 2D. Experimental results indicate that for this geometry a similar acceleration mode occurs across scales: that the flame speeds up an average of 40% as it passes over a rock pile with this profile. The model is able to capture several important features of the experimental results, including the significant increase in velocity, the speedup ahead of the rock pile, and the leveling off of the empty tube flame front propagation velocity. INTRODUCTION Explosions in underground coal mines are among the largest industrial explosions, known to result in the rapid combustion of 20m3 of fuel gas or more [1,2] Coal beds hold methane gas under pressure, and when the pressure is relieved through mining activity some of this methane is released. The methane then mixes with ventilation air and, if not sufficiently diluted, may form a combustible mixture, which may result in an explosion. Several large coal mine explosions have occurred around the world recently. These include the 2014 Soma Mine disaster in Turkey that killed 301 people [3], and the 2009 Heilongjiang Mine explosion in China that killed 108 [4]. Other recent mine explosions, including the 2010 disaster at the Upper Big Branch mine that caused 29 fatalities [5], have demonstrated that explosive gases can accumulate and ignite within and around the gob area of a longwall coal mine and then expand into the active mining face and nearby areas, endangering workers and equipment. If enough combustible gas is involved, the initial flame can accelerate, eventually transitioning from deflagration to detonation [6]. Researchers are developing a fundamental understanding of the evolution of the explosion process from the laminar kernel to the fully turbulent regime, and its propagation through obstacles such as those found in the gob. Researchers also studied the initial development of methane flames and the potential for the development of a detonation."

Jan 1, 2018

By R. Mittler

Over 100 saprolite samples from Turkey Hill Gold Mine, Lumpkin County, Georgia, were analyzed (-80 mesh) for As, Au, and Sb. Maximum values are 16.2 ppm As, 7.9 ppm Au, and 29.1 ppm Sb. Results show trace element content of saprolite varies with topography: ridge top samples show a pronounced decrease in Au and Sb, and to a lesser degree in As, whereas, slope and valley samples have anomalous Au and Sb concentrations, with no discernable pattern for As. Statistical analysis shows strong correlation between Au and Sb and none between Au and As. This study will serve as a model for gold exploration in deeply weathered terrains with variable relief.

Jan 1, 1987