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

TECHNICAL PROGRAM
ters requires certain intact rock and rock mass properties (such as abrasivity) as
well as machine parameters are needed. Analysis of cutter consumption information
of several tunnel projects from around the world has revealed that the available
models for estimation of cutter consumption require some revisions to provide
more accurate predictions. The results of the statistical analysis show that in
most cases, NTH model underestimates cutter change time. The preliminary
analysis of data shows that average cutter change time is approximately 66 minutes
for different cutter sizes and there is a minimal difference between corresponding
cutter change times of the large versus small cutters. This paper reviews
the available models for cutter life estimation and cutter consumption data from
various projects. It offers new models for estimation of cutter consumption and
cutter change time as part of TBM down time analysis.
10:05 AM
Installation of Internal Hydraulic Seals for Additional
Environmental Protection
M. Castner; Engineering, Rosebud Mining Company, Kittanning, PA
Permit applications for deep mines in the state of PA require environmental provisions
to prevent post mining water discharge. In some instances, the permit applications
have required the installation of hydraulic seals prior to the completion
of the final drift seals at a mine. Such was the case for Rosebud Mining Company
and the Little Toby Mine, located in Elk County. When the permit was approved,
it was done so on the condition that hydraulic seals would be installed and an acceptable
design was approved as part of the permit issuance. Over the years, conditions
and ideas have changed and developed which resulted in new ideas and
resources that provide some alternative ways for the construction of hydraulic
seal. Thus, the purpose of this report is to show the design of a recently installed
hydraulic seal application, how this new seal design compared to the previously
approved design, and finally how the entire installation procedure was executed
for this new hydraulic seal.
10:25 AM
Using Chemical Grout to Control Groundwater Infiltration
J. Gentry; Avanti International, Webster, TX
Acrylamide grout was selected to address groundwater seepage on three unique
projects. Each project provided special circumstances and geological conditions:
Pre-excavation grouting for combined sewer overflow tanks, 27 miles of leaking
subway, and encapsulation of radioactive hazardous waste. Acrylamide grout
was chosen primarily for its specific characteristics: thinnest grout on the market,
no suspended solids, adjustable set times, and a 362-year half-life in soil as determined
by the U.S. Department of Energy.
10:45 AM
Interaction of Roof Rock Mass Characterization and Ground
Control Design in Weak Roof Conditions
A. Osouli; Civil Engineering, Southern Illinois University,
Edwardsville, IL
Roof rock mass characterization is the critical element for evaluating roof conditions
and designing roof support systems in underground coal mines. Coal Mine
Roof Rating (CMRR) is the most internationally used and empirical-based rock
mass classification system which was developed using a limited number of case
studies. Therefore, using CMRR for cases outside its database has raised concerns.
It was discovered that the current procedure of determining CMRR may
not be appropriate for Illinois coal mines, where due to its weak and moisture
sensitive roof, has the highest number of roof falls among all the United States
(U.S.) coal regions. The erroneous roof rock mass characterization will affect the
selection of roof control methods, mining methods, and as a consequence marketability
of coal. Utilizing CMRR for roof rock mass evaluation has many advantages
including its flexibility to adapt to different roof conditions. This study
will focus on the shortcomings in application of CMRR for weak moisture sensitive
roof conditions and possible modifications to address these shortcomings.
chair:
9:00 AM
Introductions
coal & energy:
Ventilation II
9:00 AM • Tuesday, February 26
K. Luxbacher, Virginia Polytech Institute and State
University, Blacksburg, VA
9:05 AM
Studies of Controlled Recirculation Using CO2 Gas Injection:
Laboratory and Simulation Results
M. Nelson, M. Shriwas and F. Calizaya; Mining Engineering,
University of Utah, Salt Lake City, UT
As an underground mine gets deeper, ventilation systems become more complex.
Conventional methods of ventilation using only surface fans may be inadequate
because of the limitations to increasing surface fan pressure. A high main fan
pressure increases leakage and poses other risks. Controlled recirculation provided
by booster fans can offer advantages, particularly for dust and climate control.
However, the booster fans must be designed, installed, and managed properly.
This study determined the concentrations of CO2 tracer gas in intakes and
returns during controlled recirculation, the recirculation fraction for multiple
headings, and the best combination of main and booster fan pressures to achieve
allowable levels of air contaminants. Results from the laboratory model were
used to calibrate a VentSim numerical. Recirculation can increase air velocity at
the face, reducing risk by decreasing concentrations of gasses to allowable levels.
Controlled recirculation can be a safe method of ventilation, to improve the environmental
conditions at working faces and make them more comfortable and tolerable
for the miners.
9:25 AM
Hazard Identification and Risk Assessment for the Use of Booster
Fans in Underground Coal Mines
F. Calizaya, M. Nelson and M. Shriwas; Mining Engineering,
University of Utah, Salt Lake City, UT
A booster fan is an underground ventilation device installed in the main airstream
to handle the total quantity of air circulated to one or more working districts. It is
installed in a permanent stopping and equipped with airlock doors, a monitoring
system, and interlocking devices between the main fan and the booster fan. When
adequately installed, a booster fan can be used to reduce the main fan pressure, reduce
leakage, and decrease the power requirements. However, an inadequate installation
can also increase the likelihood of mine fires and recirculation of air
contaminants. This study identifies hazards associated with the operation and
maintenance of booster fans. It analyzes the accompanying risks and suggests
control barriers to reduce those risks to acceptable levels. In particular, the ventilation
network of an existing coal mine was updated to include a booster fan system.
The hazards associated with the operation of the fan were identified, the
risks analyzed, and the response to each failure mode established.
9:45 AM
Evaluation of Novel Fire Suppression Systems for
Conveyor Belt Fires
K. Teacoach and R. Thomas; NIOSH, Pittsburgh, PA
For decades the majority of underground coal mine fire suppression systems
have relied on water applied by sprinkler heads to protect the belt line. However,
many other industries utilize fire suppression systems and suppression agents
which are not listed in 30 CFR, but may be practical and effective in coal mines.
This paper summarizes eight full scale conveyor belt fire experiments conducted
under ventilated conditions in the Fire Suppression Facility at Lake Lynn
Laboratory. It also evaluates the suppression capabilities of firefighting foam and
gel in systems installed according to water sprinkler regulations, and the suppression
capabilities of a deluge-type water mist system. The efficacy of these systems
was assessed by comparing several fire characteristics and outcomes to previous
experiments with standard water sprinkler systems. All three novel systems
were able to suppress established fires located in the belt drive area as well as a
typical water sprinkler system. The results were consistent with previous water
sprinkler tests which determined water supply and nozzle placement to be the
two most important factors in the efficacy of a drive area suppression system.
This is the Technical Program as of September 1, 2012. IT IS SUBJECT TO CHANGE.
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