LAPC, under section 3.1 (a) of Schedule 1 to the Environmental Protection (Prescribed Processes and Substances) Regulations 1991, SI 472 (as amended).
LAPPC, under section 3.5 Part B of Schedule 1 of the Pollution Prevention and Control (England and Wales) Regulations 2000 SI 1973.6
This note refers to general quarry processes associated with the processing of designated minerals, but excluding:
The drilling/blasting/extraction of minerals, the removal of overburden, and the cutting and dressing of stone these are not prescribed processes.
Clay the handling of clay at quarries is not normally likely to result in the release into air of particulate matter unless crushing, grinding or screening is taking place at the quarry. The processing and drying of clay is covered by Guidance Note PG 3/ 2(04).
Sand and gravel the extraction of sand and gravel is not a prescribed process. Crushing, grinding, screening and grading of wet material is not normally likely to result in the release into air of particulate matter except in a quantity which is trivial. The drying of sand and minerals is covered by Guidance Note PG 3/15b(04).
Coal.
The manufacture of plaster from gypsum .
Chalk the processing of chalk is not normally likely to result in the release into air of particulate matter except in a quantity which is trivial.
Quarry processes that use silos may refer to the Guidance Note PG 3/15b(04) for information regarding controls relevant to silos.
Quarry processes using mobile plant for crushing or screening should use the requirements contained within this note, unless the mobile plant is separately authorised, in which case the requirements of PG 3/16(04) should be referred to.
Aggregate Quarrying processes
Hard rock is a generic term which includes minerals such as granite and other types of igneous rock, as well as the harder sandstones and gritstones. Variation occurs in both grain size and mineralogy throughout the country. Hard rock is extracted, crushed and sized and used primarily as construction aggregates. Size reduction is an energy intensive process and without adequate mitigation the potential for dust emissions is high. (A small proportion of hard rock is used as dimension stone for building but this use does not usually employ crushing and screening processes and is therefore not a prescribed process.)
Limestone and dolomite are generally softer than hard rock and are forms of calcium carbonate but dolomite has a high magnesium content. Their end use may differ from hard rock types as they are frequently used to manufacture lime, cement and fine powders for use as a feedstock for other industrial processes.
The handling and processing of both hard rocks and limestone/dolomite are similar and described below:
Quarried material is delivered to the primary crusher directly from the quarry by a conveyor or dump truck, or it may be transferred from a surge pile (which provides a large capacity storage facility). The primary crushing and screening produces material of manageable size, typically 300 400 mm in size. The screening process removes undersized material and rejects oversize material which is usually fed back into the crushing process for further size reduction. Crushed material undergoes further secondary, tertiary and sometimes even quaternary crushing and screening operations to produce a range of differently sized and shaped aggregate products. The material is generally transported between different units of plant by conveyor, enclosed to protect it from the wind. Surplus material may be deposited onto a surge pile and will be loaded back onto conveyors via vibrating feeders, or into feed hoppers by hydraulic shovel.
The aggregate products produced by the crushing processes may be further processed, either by coating with molten bitumen to form roadstone or by batching with cement and sand to form concrete. These activities are subject to PG notes 3/ 15 and 3/1 respectively.
