Restoration Thrift

Restoration is one of many operating costs and potential liabilities faced by quarry managers. In this article Simon J. Higson, principal at environmental firm SLR Consulting, sets out some ways in which the costs associated with restoration can be reduced without causing detriment to the quality and success of the scheme.

Companies are required to record the fair value of closure costs incurred at any time during the life of an asset under the provisions of the Financial Accounting Standards Board Statement No. 143: Accounting for Asset Retirement Obligations, 2001 (with additional clarity provided in Interpretation No 47: Accounting for Conditional Asset Retirement Obligations, 2005).

For the minerals industry, this provision will usually cover items such as the decommissioning of quarry plant and/or the final or progressive restoration of the site.

In restoration terms, the existing planning permission will be the main influence on the scope of this liability, as this will set out the Local Planning Authority’s (LPA) specific requirements for a site that must be met by the operator. A legal agreement with the landowner or other parties may also set out further requirements.

Inevitably, any restoration work already completed on site will also provide a base against which alternative schemes and future work will be judged by stakeholders. Many operators have achieved considerable success after restoration and these set a strong precedent.

Nevertheless, cost savings can be gained by: reviewing agreed items, such as the final landform, profiles and techniques; the general arrangement of after uses, plant establishment and aftercare; or simply by paying closer attention to the method of working, restoration design and specifications.

Restoration landform

All landform modelling needs to be carried out as part of the stripping operations and directly placed where possible. A phased scheme of working and restoration that minimizes double handling and haul routes should then be carefully prepared, prior to the commencement of works.

The permitted restoration landform should be reviewed in light of the existing circumstances on site. Often older heaps of subsoil can develop interesting ecological communities and there may be benefit in retaining them in situ as part of a revised scheme, minimizing volumes of cut and fill and reducing overall costs.

Any low-level agricultural restoration schemes worked sub-water table, and that require continuous pumping to preserve soils, also need to be reviewed. New wetlands and associated habitats are targeted by many national and local biodiversity action plans. In some cases it may be acceptable to allow the site to flood and permanently submerge the soils or for the soils to be recovered before flooding and sold off site for beneficial use elsewhere.

Restoration profiles and techniques

Earthmoving specifications and the performance of contractors should be reviewed. For agricultural or forestry after-uses, compaction should be avoided and the handling of all soil and other material within the upper restoration profiles should be properly carried out to avoid the need for subsequent mechanical de-compaction or ripping.

Ensuring that all contrasting soil and overburden units are recovered and handled separately will avoid mixing and the loss or denaturing of essential materials, allowing the most economical use of available resources to be determined.

Restoration profiles and thicknesses should also be reviewed to determine whether these are still considered appropriate and best practice for the proposed after-use.

Restoration after-use

Combinations of agricultural land, nature conservation, forestry, recreation or built development will each incur differing items or treatments so the approved restoration after-use needs to be reviewed. For example, agricultural land may require under-drainage, while conservation grassland may not; localized ponding and wetter areas provide habitat diversity.

Recreational after-uses may require access and/or other facilities, ranging from informal stiles and grass paths to more elaborate dog-proof gates, designated and surfaced multi-user routes for cyclists, disabled access, vehicle barriers and way-marking. Quarry hardstandings and entrances could be retained and incorporated for car parking and highways access.

Nature conservation areas and habitat-creation schemes, although typically less intensive in terms of management inputs, may not be wholly without special items. For example, bird hides or nesting boxes and, increasingly, agreements for long-term management beyond the statutory five-year aftercare.

Plant establishment

The options for establishing plants should be reviewed. Steep slopes in visible or conspicuous parts of the site would benefit from early grass seeding to help stabilize the surface and minimize erosion/run-off, as well as assimilating with the surroundings.

Less visible areas of the site that are part of a nature conservation scheme, on the other hand, may benefit from allowing natural regeneration either from the seed bank in the reinstated soil or from wind-blown seed. A wide range of habitats can eventually establish in this way. Alternatively, grass seeding at a low rate can provide an open matrix and allow natural regeneration of grasses and wildflowers.

Agricultural and forestry planting schemes may require fertility to be increased to encourage growth, whereas nature conservation schemes may benefit from the omission of fertilizer to suppress vigorous grasses, which can smother and supplant the preferred wildflowers, so fertilizer requirements should be reviewed.

The size and shape of plantations should be reviewed, as it may be more cost-effective to fence off larger compartments, rather than using individual guards or shelters.

Aftercare

Review replacement requirements for seeding or plant failures as many LPAs vary their percentage requirements – a commitment to a 95% success rate would be less costly than ensuring 98% or 99%, while not necessarily affecting the long-term success of the scheme.

In addition, aim for early treatment of emerging noxious weeds, such as Japanese knotweed, to reduce potential costs as, if left unchecked, they could spread and colonize a larger area.

Conclusion

The costing of restoration liabilities is site specific and directly related to the circumstances of the deposit, stage in the development and the nature of the restoration scheme.

Furthermore, like most services and goods, restoration rates will be subject to variation at the time of appointing contractors according to market conditions or other influencing factors.

Fostering good relations with the LPA is vital to reach agreed standards and expectations. Restoration schemes are undoubtedly part of the permanent legacies of mineral extraction and are increasingly being given equal weighting in the planning application and environmental impact assessment.

Nevertheless, cost savings are possible, without necessarily causing detriment to the quality and success of the scheme, and the quarry manager should plan carefully the various options available.