Middleton Quarry

VHE were approached by Dalkeith based NWH Group to look at possible options to provide a lining to their Quarry at North Middleton, Gorebridge, Scotland.

SEPA recently published draft guidance on “the recovery and disposal of waste in quarries” and imposed this guidance on NWH requiring them to submit a Pollution Prevention and Control Permit Application detailing a liner system.

Historically, such works would have been undertaken under a Waste Management Licencing Exemption paragraph 9 or paragraph 19. Under section iv of the draft guidance the Financial Considerations were judged to determine the operation disposal and not recovery. This is the first case to be determined under the draft guidance which was published for consultation.

VHE assisted, along with NWH Group designers Dalgleish Associates, in developing a solution and preparing information for the PPC application. VHE suggested the use of a combination of materials GCL (Geocomposite Clay Liner) for basal and reworked clay filter press clay from NWH recycling facility for sidewall lining. Bentomat AS5000, manufactured by Cetco, was selected as the GCL with the clay tested to ensure it met the permeability requirements.

Following the installation of underdrainage to relieve water ingress VHE placed regulating material to the 13,500m2 quarry floor before placing the GCL and containment soil layer. A perimeter clay tie in detail was constructed to allow future placement of clay up the quarry wall to be progressed with the placement of fill.

The works, which commenced in March with CQA verification undertaken by TerraConsult, were successfully completed in April 2017 despite some difficult weather conditions and verification was submitted to allow NWH to commence filling in May.

Since the business was established VHE has developed an excellent reputation for being able to deal with a wide variety of projects. Many of these have involved the remediation of historical former landfill sites, a large number of which were unlicensed with little control over the material deposited. This experience and knowledge is invaluable to modern landfill site operators and waste companies who are tasked with managing and developing their facilities in a controlled and efficient manner.