Annual Meeting Preliminary Program - Full Brochure (PDF) - SME

TECHNICAL PROGRAM
side it. The results also show that the size of the recirculation regions increased
with the increase in the angle of the overcast influencing significantly the flow
field and pressure losses. Results for the pressure and velocity distributions and
the effect of overcast angles on these results are presented. The streamlines are
also plotted to show the three-dimensional structure of the flow field. The results
from the simulation can guide design of overcast in underground coal mines.
3:05 PM
Ventilation Risk Management in Underground Coal Mines:
Atmospheric Monitoring in the United States
K. Griffin 1 , K. Luxbacher 1 and M. Karmis 2 ; 1 Mining and Minerals
Engineering, Virginia Tech, Blacksburg, VA and 2 Virginia Center for
Coal and Energy Research, Virginia Tech, Blacksburg, VA
Atmospheric conditions underground are constantly trending which makes it
necessary to examine a mines ventilation using a risk based approach. The implementation
of risk assessment and management allows operators to identify
comprehensive site specific ventilation parameters, trends, and modify ventilation
plans as a mine develops. Atmospheric monitoring in underground coal mines allows
mine operators to analyze atmospheric conditions underground in real-time.
Real-time monitoring can be used to identify whether atmospheric conditions underground
are abnormally trending or have become problematic. Ventilation risk
assessment and management allows developing atmospheric monitoring technologies
to be fully utilized in order to increase safety standards in the United
States. This paper reviews general risk assessment approaches, state of the art
ventilation based risk assessment, and risk assessment and management application
within the United States regulatory framework.
3:25 PM
Impact of Nitrogen Inertization on Methane Distribution in
Bleederless Longwall Gobs
J. Brune, D. Worrall, J. Grubb and D. Munoz; Mining Engineering,
Colo. School of Miners, Golden, CO
Underground longwall coal mining sections are operated as bleederless or sealed
gobs if the coal is prone to spontaneous combustion. Sealing along the gate roads
as the longwall face retreats limits the flow of fresh air into the gob and thus deprives
spontaneous combustion of oxygen. In a project sponsored by the National
Institute for Occupational Safety and Health (NIOSH), researchers at the
Colorado School of Mines have used computational fluid dynamics (CFD) modeling
to simulate the flow of gases in longwall gobs. Following validation with
limited operational mine data, the models indicate that targeted injection of nitrogen
along the gate roads inby the face can be used to control the size and location
of methane and air clouds within the gob and to minimize or eliminate the
explosion hazard resulting from the formation of flammable methane-air mixtures
in longwall gobs.
chair:
2:00 PM
Introductions
environmental:
Geological Influences on
acid Mine drainage
2:00 PM • Tuesday, February 26
D. Carpenter, ARCADIS, Brighton, MI
2:05 PM
Understanding Uranium Roll-front Ore Body Formation Aids in
Predicting Mine Closure Challenges
D. Carpenter; ARCADIS, Brighton, MI
Previous work (Carpenter, 2012) documented the specific benefits associated
with application of the understanding of the ore genesis of porphyry copper deposits
to acid mine drainage potential and associated mine closure challenges.
This present work will continue this discussion and focus on the currently accepted
ore genesis model for uranium roll-front type deposits; an important uranium
ore body-type especially within the United States. This presentation will describe
the evolution of geochemical conditions leading to ore body formation and
the geochemical effects induced by open pit mining and how these may be used to
understand both the geochemical controls and constraints on residual mine
water. The consequences of thess processes will be shown to represent specific
mine closure challenges. Reference Carpenter, D. J., 2012, Understanding How
Ore Body Formation Aids in Predicting Acid Mine Drainage Potential, SME
2012 Conference.
2:25 PM
Microbial Ecology of Iron Cycling in Mined Environments
L. Kirk, L. Bozeman and M. Kozubal; Enviromin, Inc.,
Bozeman, MT
Biogeochemical cycling of iron is critically important to effective management of
acid rock drainage, trace element attenuation, and carbon cycling in mined environments,
but its control requires better understanding of microbial community
structure and metabolism. A data mining approach has been employed to compile
and characterize the geomicrobiology of iron cycling in mining environments
worldwide where geochemistry, microbial populations and metabolic data
have been published. Results show important differences in microbial ecology depending
on mineralogy, aqueous chemistry, pH, and temperature, and suggest
that conceptual geochemical models of iron cycling can be significantly expanded
through inclusion of microbiological data. Analysis of isolate and environmental
genomes is especially valuable in characterizing the metabolic potential
of in situ microbial communities. This work also indicates important gaps in
understanding of geomicrobiology in mining environments, and offers insight
into methods need to address gaps in knowledge about biogeochemical processes
of critical importance to the mining industry.
2:45 PM
Mineralogical Characterization for Environmental Applications
K. Smith 1 , K. Olson Hoal 2 and K. Pietersen 3 ; 1 Crustal Geophysics
and Geochemistry Science Center, USGS, Denver, CO; 2 JKTech Pty
Ltd., Denver, CO and 3 JKTech Pty Ltd., Brisbane, QLD, Australia
Characterization of ore and gange material using quantitative micro-mineralogical
and elemental techniques (e.g., Electron Probe Microanalysis (EPMA),
QEMSCAN, and Mineral Liberation Analysis (MLA)) have the potential to
complement traditional acid-base accounting techniques when predicting acid
generation and metal release from waste rock. These characterization techniques,
which are currently being used for metallurgical and geometallurgical applications,
can be more broadly applied throughout the mine-life cycle to include environmental
applications. Critical insights into mineral liberation, mineral associations,
particle size, particle texture, and mineralogical residence phase(s) of
environmentally important elements can be used to anticipate potential environmental
challenges. Mineralogical and textural information can be used to help interpret
predictive tests. Resources spent on initial characterization result in lower
uncertainties of environmental impact and potential cost savings associated with
remediation and closure. Examples illustrate mineralogical and textural characterization
of tailings and mining waste materials from sites in the western USA.
3:05 PM
Predicting Total Dissolved Solids Release from Overburden in
West Virginia
J. Skousen, J. Odenheimer and L. McDonald; West Virginia
University, Morgantown, WV
Tthe Appalachian coal industry has been successful in developing technologies to
identify, handle, treat and isolate potentially acid-forming overburden materials
at coal mines in the region. However, the techniques to predict acid mine
drainage potential do not adequately predict the release of total dissolved solids
(TDS). Our objective was to determine the effect of different acidic solutions on
overburden dissolution and the release of constituents contributing to TDS.
Fifteen overburden samples (five strata from three locations) were collected from
surface mines in West Virginia. Ground samples were leached separately with dilute
HNO3 acid, EDTA, and HF acid to obtain the most accurate in-lab experiment
to determine TDS release from overburden materials. Supernatants were
analyzed biweekly for pH, EC, TDS, and other selected ions. Leachate pH was
initially low at around pH 2.0 due to the acid used to leach the materials, but the
majority of the samples quickly increased to pH greater than 7.0. Leachate EC (a
surrogate for TDS) showed high levels initially (some as high as 2,000 uS/cm)
but they quickly dropped to