Table 7.23.

Summary of terrain and types of equipment suitable for gaining assess

TerrainSI phaseChoice of plant/drilling method
Soft and/or waterlogged groundPreliminary
  • Hand-held auger;

  • Hand-held window sampler;

  • Hand-held penetrometer;

  • Window sampler/dynamic probe equipment mounted on low-ground-pressure tracked chassis;

  • CPT equipment mounted on low-ground-pressure track unit.

Main/detailed
  • CPT equipment mounted on low-ground-pressure track unit

  • Multi-purpose soft ground rig mounted on low-ground-pressure-tracked chassis;

  • Conventional drilling plant used in conjunction with temporary access roadways;

  • Modular cable percussion rigs which may be disassembled into their component parts and carried by hand or on all-terrain vehicles to the drill site.

Rugged terrain/access routesPreliminary
  • Hand-held auger;

  • Hand-held window sampler;

  • Hand-held penetrometer;

  • Track-mounted window sampler/dynamic probe;

  • Track-mounted CPT equipment.

Main/detailed
  • Track-mounted CPT equipment;

  • Track-mounted multi-purpose soft ground rig/rotary rigs;

  • Conventional drilling plant used in conjunction with specially constructed haul roads;

  • Modular cable percussion rigs;

  • Skid-mounted drills and ancillary plant carried by all-terrain vehicles or lifted into position by helicopters.

Confined or restricted access routes.Preliminary
  • Hand-held auger;

  • Hand-held window sampler;

  • Mini-track-mounted window sampler/dynamic probe;

  • Mini-track-mounted CPT.

Main/detailed
  • Mini-track-mounted CPT;

  • Mini-track-mounted multi-purpose soft ground rig/rotary rigs;

  • Modular cable percussion rigs.

Shallow inland waterways, lakes, saltings and mudflatsPreliminary
  • Hand-held augering, window sampling, or probing carried out from mini drilling pontoons or small work vessels and hovercrafts;

  • Mini-track-mounted window sampler/dynamic probe carried out from mini drilling pontoons;

  • Mini-track-mounted CPT carried out from mini jack-up drilling platform.

Main/detailed
  • Small track or skid-mounted conventional rigs deployed on drilling pontoons or mini jack-up drilling platforms.

Nearshore marine waters, rivers and estuariesPreliminary
  • Vibro-coring from small marine survey vessels;

  • Seabed CPTs deployed from marine survey vessels;

  • CPT carried out from JUB drilling platform.

Main/detailed
  • Conventional drilling and sampling equipment deployed from modular pontoons and JUBs;

  • In situ testing deployed from JUBs;

  • CPT deployed on JUBs;

  • Drill ships.

Offshore waters (>25 m water depth)Preliminary
  • Large drill ship with dynamic positioning, heave compensation or mooring systems to deploy rotary drilling or seabed CPT.

Main/detailed