Dust control during dry transportation, transloading and pneumatic placing of new mining materials, including determination of the conditions for conversion to hydraulic placing

Ziel

In two ealier research projects, work concentrated on determining dust make around the discharge points of pneumatic conveyors and developing appropriate dust suppression methods. In this project, further work on these areas will be supplemented by

- analysis of various construction materials for content of harmful substances, the resulting content formulae to be used as the basis for establishing criteria for use,
- determination of dust make at transloading points e.g. scraper-loaders, and development of suppression methods,
- improvement of dust control at transfer points between different conveyor systems,
- determination of the conditions necessary for conversion to hydraulic placing following pneumatic transportation.
The dust control studies undertaken on new mining materials (construction materials to which certain amounts of incinerator ash had been added) have shown that the variation in the heavy metal contents of the new materials is substantially greater than in the materials used hitherto. However, heavy metal levels were not found to be universally higher. The lead content of the new materials in partiuclar tended to vary more than the levels of other heavy metals.

Dioxin and furan levels were higher in the new materials examined than in the conventional material examined. A greater proportion of filter ash from waste incinceration was reflected by a rise in the dioxin and furan levels.

It is proposed that individual values for particularly toxic substances such as 2, 3, 7, 8-TCDD and elements with a tendency towards more substantial variation (e.g. lead) be laid down, together with cumulative values for selected substances for which recommended and maximum workplace concentrations exist and for dioxin and furan isomers.
The use of building materials underground for construction of packs, consolidation and backfilling has been increasing for many years. The predominant system is still pneumatic transportation from the shaft to the discharge point with or without intermediate bunker storage. However, transport in containers with intermediate storage and subsequent transfer to pneumatic or hydraulic transport systems via scraper loaders, or screw or chain conveyors is also common.

In the past, the materials most often used were anhydrite-based construction materials with or without the addition of dihydrates from flue gas desulphurization plants. Now, however, iron and potassium sulphate-based hardening agents are increasingly being replaced with calcium-hemihydrates and particularly cement containing power station waste, to guarantee the requisite properties. The presence of heavy metals, particularly in power station ash, cannot be ruled out. These will vary according to coal charge, type of furnace and type of ash. As yet, however, too little is known about the presence of these harmful substances in the dust produced during the handling of construction materials. Use of materials in powder form will obviously create higher initial dust levels. There is therefore an increasing need for better suppression methods at dust sources.

Along with wet dust control processes, new measures and techniques will be developed in the areas of:

- screening off;
- enclosure;
- exhaust ventilation.

Potential improvements to the construction materials themselves will also be tested, e.g. alteration of particle distribution, and the feasibility of conversion to hydraulic placing of pneumatically transported materials will be investigated.

The tests will largely be carried out in operational workings underground but for certain points of detail, laboratory conditons will preferred, as this will allow more accurate control of test parameters.

Programm/Programme

ECSC-MINEHYG 6C - Sixth research programme (ECSC) "Industrial Hygiene in Mines", 1990-1993

Thema/Themen

1 - Technical control of pollutants

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

Data not available

Koordinator

Institut für Gefahrstoff-Forschung der Bergbau-Berufsgenossenschaft

EU-Beitrag

Keine Daten

Adresse

Waldring 97
44789 Bochum
Deutschland

Gesamtkosten