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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.

Through this project the joint UoN and UKCL research teams have developed an improved understanding in five areas.

  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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:

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:

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.

Updated 2013-12-23