HILLINGDON UNITARY DEVELOPMENT PLAN - London Borough ...

(iii)
THE RETENTION ON SITE OF ALL BRICKEARTH TOPSOILS AND SUBSOILS FOR
USE IN RESTORATION.
Chalk Extraction
13.29 The only recent chalk extraction has been from a quarry at Harefield, on a small-scale basis by a
company which has now ceased operations. The chalk was extracted for agricultural purposes. There is
considered to be little likelihood of new proposals and any application would be considered on its merits.
Having regard to the location of existing former chalk quarries on the escarpment along the eastern edge of
the Colne Valley demonstrable harm would be virtually inevitable to this dominating landscape feature if
further working occurred.
MIN13 THE MINERALS PLANNING AUTHORITY WILL NORMALLY OPPOSE
APPLICATIONS SEEKING CHALK EXTRACTION FROM THE ESCARPMENT ON THE
EASTERN EDGE OF THE COLNE VALLEY PARK. IT WILL ASSESS APPLICATIONS
ELSEWHERE ON THEIR MERITS, HAVING PARTICULAR REGARD TO THE
ALTERNATIVE SOURCES AVAILABLE.
Mineral Working and Archaeology
13.30 Past mineral workings have yielded finds which are not only valuable individually but which
collectively enhance knowledge of the history of West London. General policies for archaeology are set
out in Chapter 5; however mineral working presents some special considerations. Because they are much
longer term than most building projects there can be more scope for flexibility in the timing of investigative
works. The Minerals Planning Authority would prefer to see this primarily as a matter for close cooperation
between minerals operators, archaeologists and landowners. Nevertheless it has a statutory duty
to satisfy itself that adequate arrangements are in place before any mineral extraction works commence and
to ensure that phasing of mineral extraction proposals and the conditions imposed on any permission (if
necessary backed by legal agreement) provide an effective means of resolving the situation in the event of
voluntary co-operation breaking down.
13.31 The Planning Authority considers that wherever possible a full archaeological field evaluation
should be carried out to assess archaeological importance prior to preparation of mineral working
applications. It nevertheless recognises that, unlike most building projects, mineral working is a large scale
continuing process often undertaken while other uses are continuing elsewhere within the application area.
Likewise other uses are not normally displaced until that phase of mineral extraction is imminent and this
can present difficulties in securing the agreement of landowners and users to full preliminary investigation
by trenching exploratory works before mineral extraction is commenced and other land uses have ceased.
13.32 Applicants are advised to seek expert archaeological advice at the outset and then to discuss with
the Minerals Planning Authority the timing and phasing of investigation appropriate to the likely
archaeological importance. Particular attention should be given to the advice in Policy Planning Guidance
'Archaeology and Planning' (PPG16) and to the current Confederation of British Industry's Code of Practice
on mineral working agreed with the County Archaeologists’ and County Planning Officers’ Societies. The
Minerals Planning Authority may nevertheless require other arrangements in exceptional circumstances
where these more general arrangements require modification to provide safeguards to meet specific
concerns about their adequacy. In particular the Minerals Planning Authority may request that an applicant
wishing to defer full preliminary field evaluation of the whole site until after a permission is given should
indemnify the Minerals Planning Authority against any subsequent claim for loss in the event of important
discoveries delaying mineral extraction and/or sterilising part of the permitted reserve or in the event of it
being necessary to preserve finds in situ. The primary objective will be to ensure that no mineral extraction
actually commences until archaeological investigation has been completed on that phase.
MIN14 WHERE MINERAL EXTRACTION IS PROPOSED IN A LOCATION WHERE THE
MINERALS PLANNING AUTHORITY IS ADVISED THAT THERE IS A STRONG
PROBABILITY OF SIGNIFICANT ARCHAEOLOGICAL DISCOVERIES REQUIRING TIME
London Borough of Hillingdon Unitary Development Plan