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Contenido archivado el 2022-11-21

Clearance of blockages in bunkers and boreholes

Objetivo

Blockages frequently occur in mineral clearance bunkers and boreholes in underground coal mines, particularly where the composition of the mineral and its moisture content are such that it is of a clinging consistency. Serious injuries and fatalities occur as a result of sudden unpredictable release of mineral when attempts are being made to clear blockages; five men have been seriously injured and seven men killed in the United Kingdom in the nine years ending March 1990 for this reason.

The purpose of this proposal is to develop a portable means of blockage clearance to be used after the failure of existing fixed means of clearance which will restore normal mineral flow in speed and in safety, without workmen having to work in a danger zone
A review was undertaken into the measures already being applied to clear blockages. These included the use of vibrators, air cannons and water jets and the use of suspended chain systems. Although it was determined that each of these systems could assist in the resolution of the problems the investigation confirmed the requirement for a mobile clearance system.

Extensive searches identified two possible systems which appeared to have the potential to overcome the problems. The first, 'The Ferret', consisted of an air driven rotating head suspended from an articulated arm. Arrangements were in hand to undertake a surface trial of this machine but the trial was abandoned when the colliery closed. Sufficient work was undertaken into the Ferret to indicate that the device did have applications in preventing blockages from occurring by being able to flail the sides of a bunker but as a means of clearing blockages would require a pre driven hole. A second device, 'The Vibradriver' did offer opportunities for piling through a bunker blockage. Surface trials on compacted run of mine material indicated that the equipment would undertake such a task. A specification was developed for the adaptation of this equipment to make it suitable for use underground. In November 1993 British Coal made the decision to discontinue work on this project due to the continuing contraction of the size of the UK coal industry and the recognition that the project had resulted in the identification of two systems either of which were capable of being developed by manufacturers and applied at individual collieries.
Initially, a feasibility study will be undertaken to determine possible methods of blockage clearance, and the applicability of these methods to typical blockage conditions and bunker and borehole configurations employed in coal mines.

This study will encompass methods used outside the coal industry, as well as those used within it. Insofar as the latter methods are concerned, the study will also consider how existing methods such as air cannons, limpet vibrators, water jets, and moving chains might be improved. However, the main thrust of the study will be to identify clearance methods which would normally be used after any fixed aid to blockage clearance has failed.

On completion of the feasibility study, the most promising method will be selected for development of the technique for use in coal mines. The development will be undertaken in conjunction with a suitable manufacturer. The development will address problems such as equipment portability, ease of installation and use, interface with existing fixed blockage clearance aids, and personnel safety.

Prototype equipment will then be manufactured and demonstrated under controlled conditions on the surface. Following successful completion of such trials, the equipment will be used underground to clear an actual blockage as and when it might occur

Convocatoria de propuestas

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Régimen de financiación

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Coordinador

British Coal plc
Aportación de la UE
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Dirección
Eastwood Hall
NG16 3EB Eastwood
Reino Unido

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Coste total
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