Guidelines for Drilling

Both groundwater and surface environmental concerns must be considered, and the location planned so as to minimise or avoid interference with water or pollution sources. Where possible, drillholes should be located downhill from water sources and karst features, and uphill from any pollution sites. There must be full compliance with requirements under the Local Government (Water Pollution) Acts, 1977 to 1990. A photographic record should be kept for all sites, showing the situation before, during, on completion and after a suitable rehabilitation time has elapsed. For certain environmentally sensitive areas (e.g. wetlands), it may be necessary to use modified vehicles for minimum access damage.

Vehicle access routes to the site should be agreed in advance with the landowner.

Where there is a possibility of artesian conditions, precautionary steps should be taken to handle the water flow. If artesian conditions are encountered, the flow must be shut off within the lithological unit in which such conditions arise. If the drillhole is collared in unconsolidated overburden likely to contain an aquifer, the casing should be kept at least 300mm above ground level and the return water prevented from entering the casing area. If groundwater pollution is a potential problem or if there is any groundwater flow from drilling operations, the drillholes should be fully sealed. Where future re-entry of a drillhole is envisaged, secure and lockable caps must be fitted.

Since both fuel and hydraulic oils are used by drilling and pumping equipment, fail-safe storage and anti-vandal spillage precautions must be taken. Bulk tanks should be kept locked and in secure locations well away from areas where spillage could affect people or stock. Fuelling procedures should be specified for contractors and separate containers kept in the vicinity of unattended rigs or pumps should be made secure. Pumps should be located far enough back from water sources so that any pollution can be contained. In case of spillage, contingency provisions should be on hand (e.g. straw bales), and remedial action immediately undertaken. The exploration company is totally responsible for all materials, liquids or other substances brought onto the land and any consequential damage resulting from these materials.

As regards drilling water, the following procedures must be adopted:
(a) Check pumping location relative to downstream abstractions for potable or animal drinking water. If significant abstraction impact is likely, users should be notified, where possible, and their agreement sought, especially in periods of low flow; (b) Where the water quality is suspect it should be analysed, and contaminated water must not be used. Should bacterial contamination be suspected during drilling, the drillhole should be disinfected (chlorinated) before abandonment; (c) Return water should be treated by settling to minimise the possibility of solids being made available to grazing animals; (d) Return water, even after settling, should not be discharged directly into a watercourse. Discharges should be allowed to percolate to the watercourse, allowing further filtering of the return water.

Care should be taken to minimize damage to vegetation, and on cessation of drilling and clearance of the site, rehabilitation should be commenced at the earliest appropriate time.

Noise problems can arise when drilling in proximity to residential areas. Where drilling and pumping must take place in such locations, care should be taken to reduce noise emissions, at source, to acceptable levels and activity should not be permitted during unsocial hours.

In addition, drilling and pumping sites should be securely fenced to exclude grazing animals; drill rods should be stacked in the safest possible manner, inside the site; all oils and greases should be securely stored and at no time should grease be accessible to livestock; the highest possible standard of housekeeping should be insisted upon on the drilling site, storage and assembly areas and meticulous clearance carried out when work is completed; on completion of the work the site and the access routes should be restored to their condition prior to commencement, or as close thereto as possible; in any event, the restoration must be to the satisfaction of the landowner, and if compensation or rehabilitation is required it should be finalised without delay.