Safety and health in mines research advisory board
Annual Review 2004
CONTENTS
MINE ENVIRONMENT
Improvement of Climate Conditions in Hot High
Performance Workings
University of Nottingham (UoN) and UK Coal Ltd (UKCL)
research teams have completed their contributions to
European Coal and Steel Community (ECSC) project
7220-PR/116. They designed, conducted and evaluated the
following series of the comprehensive underground
ventilation and climatic surveys.
- The climatic and ventilation survey at a longwall
district
- The climatic and ventilation survey at a development
drivage
- The climatic and ventilation survey at top and
bottom of the downcast shaft
- The climatic and ventilation survey of the
temperature increase across a 90 kW auxiliary force fan
at Stillingfleet, Wistow and Rossington Collieries.
- The geothermal survey (VST) at development drivages
and underground workings within UK Coal.
Through this project the joint UoN and UKCL research
teams have developed an improved understanding in five
areas.
- The development of a comprehensive geothermal and
heat source database for some high temperature mine
workings within the UK.
The Safety and Environment Department of UKCL
collected geothermal data in the vicinity of high
temperature longwall and rapid development workings. This
task involved the drilling of suitable boreholes within
the coal measure strata adjacent to current development
and production workings at a number of UK Coal
collieries. A geothermal probe was inserted within these
boreholes to log the average geothermal virgin strata
temperature. The UKCL research engineers have conducted
this work in liaison with the Protec-DMT engineers on the
procedures in the installation of the geothermal probes
and the interpretation and use of data.
Preliminary field evaluation studies have been
conducted to identify the optimum installation positions
of the temperature/humidity probes and logging units
within the various types of climatic zones under
study.
- The analysis of the survey results to improve the
understanding of the contributions of the various
sensible and latent heat sources to the production of the
mine climate experienced within the workings.
The UoN team has collated the geothermal probe data
obtained from the collieries included in the survey. This
data has been analysed in the update of the current
geothermal map of the particular colliery. This database
may be used to assist in the environmental planning of
current and future mine workings.
The temperature/humidity data has been
cross-correlated with the equipment usage and location
database, and the mineral tonnage production schedule
data. This analysis examined and identified the thermal
contribution of the sensible and latent heat sources to
the mine climate during the various production,
development transport phases of the mineral extraction
process, and also in the weekend no-production
period.
The major heat sources within the district included
the surrounding strata, equipment, and the newly cut
minerals on the conveyor belt and on the AFC, cooling
water, dust suspension spray and goaf.
- The quantifications of the contribution made to
mine climate by the dynamic heat storage potential
provided by the installed equipment and strata within the
workings.
The UKCL engineers have performed a mechanical,
electrical, power and service water usage audit of the
equipment installed within the major mineral transport
roadways, development and longwall workings of the
collieries included in the survey programme. Information
collected included: the shift pattern; the nominal and
actual power of equipment; the location of installed
equipment; the location and duty of switch gear and
transformers; the location of water ranges and the
location and rate of water use; the locations of major
ground water ingress to workings; the extent of wetted
wall and floor areas. Average power usage, average daily
mineral tonnage produced by the longwall and development
workings was monitored.
- The development of improved colliery heat load and
heat exposure mapping procedures.
The UoN and UKCL research teams have employed the
measured temperature/humidity data together with
ventilation data supplied by the colliery in the
development of the improved heat load and heat exposure
mapping procedures.
- Further development and validation of climate
prediction and mine design computer models.
These models will assist the engineer to plan mine
workings that maintain a comfortable mine climate within
high temperature environments.
Improved gas capture and climate control within high
performance workings
MRSL and UoN are both contributing to this project,
with UKCL collaboration, part funded from the EC Research
Fund for Coal and Steel (RFCS), set up following the
expiry of the ECSC treaty, through contract RFC-CR-03010-
SAFETECH.
The overall objective of MRSL's work is to provide an
improved understanding of the ability and shortfalls of
working, emergency procedures and rescue in arduous
climatic and environmental conditions as depth and
distances increase in coal mines. Subsidiary objectives
include:
- Develop hand held, intrinsically safe
instrumentation for real time graphical representation
of local mine environmental conditions and basic
effective temperature (BET);
- Development of an integrated thermal risk assessment
methodology;
- Improvement of emergency procedures and rescue in
high heat stress conditions.
To provide the background to the various tasks, a
review of thermal physiology and physiological
measurement techniques has been undertaken. This review
covered the following primary topics:
- Review of underground climatic conditions
- Management of heat stress in the industrial
workplace
- Mining guidelines and practice
- Core body temperature analytical models
- Monitoring of core body temperature and heart
rate
The first part of the study surveyed underground
climatic conditions and examined what constitutes
practical safe limits in physiological terms. The
subsequent part of the review has examined thermal
analytical models, measurement principles and
instrumentation options for determining key physiological
parameters. Focus has been put on the measurement of deep
body core temperature, since there is a variety of
previous research and anecdotal observation, which
confirms that this is the most critical physiological
parameter concerning physical activities carried out in
hot and humid underground mine conditions. The work in
the latter part of the reporting period concentrated on
determining the characteristic behaviour and accuracy of
candidate measurement techniques, initially considering
application in research investigations, but subsequently
considering possible use in the workplace.
The emphasis here was twofold; firstly to identify
measurement methods which have validated accuracy and
response time, and secondly, to identify non-invasive
temperature measurement techniques which could lead to
practical, robust intrinsically safe instrument
implementations.
A design investigation was also commenced on the
feasibility of developing and designing an ATEX
intrinsically safe instrument to monitor BET. A
preliminary design study has been undertaken, including
consideration of a novel, low cost anemometer approach
for use within a practical BET monitor.
The research work conducted by the University of
Nottingham has involved data acquisition, data analysis
and computerised numerical modelling of the strata
permeability for the first case study site project,
namely that of Panel 43 Thoresby Mine, North
Nottinghamshire.
The data obtained from the mine site has included
detailed panel layout plans showing the relative position
of the panels and adjacent panels, borehole logs and
details in relation to the drainage scheme used for the
adjacent panel and that will be adopted for Panel 43.
Utilising this information a series of models were
constructed using the numerical software code FLAC
(Itasca 1995). The outputs of the numerical models in
relation to fracture planes development, stress
redistributions and strata permeabilities were derived.
This information was used to determine four distinct
regions of characteristic strata permeability.
The project continues to February 2007.
