Search Results

rotary air blast drilling original
notation 2.2
broader
percussion drilling original
definition Percussion rotary air blast drilling (RAB) drilling is an 'open hole' rotary percussion drilling method where rock or sediment chips are derived by using a drag bit or pneumatic reciprocating piston-driven hammer, and the cuttings are blown up the outside of the drill rods by air, or a combination of air and foam, and collected at the surface. It is used most frequently in the mineral exploration industry.
air core original
notation 6
definition Air core drilling and related methods use hardened steel or tungsten blades to bore a hole into unconsolidated ground. The drill bit has three blades arranged around the bit head, which cut the unconsolidated ground. The rods are hollow and contain an inner tube which sits inside the hollow outer rod barrel. The drill cuttings are removed by injection of compressed air into the hole via the annular area between the innertube and the drill rod. The cuttings are then blown back to surface up the inner tube where they pass through the sample separating system and are collected if needed. Drilling continues with the addition of rods to the top of the drill string. Air core drilling can occasionally produce small chunks of cored rock.
auger original
notation 1
definition Auger drilling is done with a helical screw which is driven into the ground with rotation; the earth is lifted up the borehole by the blade of the screw. Auger drills may be either rotated by hand or mechanically driven. Hollow stem auger drilling is used for softer ground such as swamps where the hole will not stay open by itself for environmental drilling, geotechnical drilling, soil engineering and geochemistry reconnaissance work in exploration for mineral deposits. Solid flight augers/bucket augers are used in harder ground construction drilling. In some cases, mine shafts are dug with auger drills. Small augers can be mounted on the back of a utility truck, with large augers used for sinking piles for bridge foundations.
narrower
hand auger original
power auger original
box core original
notation 7
definition A sampling method that obtains a large volume or large surface area core with shallow penetration and minimum disturbance. Commonly uses a double spade system.
cable tool drilling original
notation 2.1
broader
percussion drilling original
definition A percussion drilling method that uses a heavy drilling tool that is raised and lowered with enough force to pulverise the rock, with the debris removed by a bailer. Although this drilling method has largely been supplanted in recent years by other, faster drilling techniques, it is still the most practicable drilling method for large diameter, deep bedrock wells, and in widespread use for small rural water supply wells. The impact of the drill bit fractures the rock and in many shale rock situations increases the water flow into a well over rotary. Many large diameter water supply wells, especially deep wells completed in bedrock aquifers, were completed using this drilling method.
cone penetrometer test probe original
notation 9.1
broader
probe original
definition A metal rod with an instrumented cone tip pushed by hammering or hydraulically into weakly consolidated ground at a controlled rate. Tip resistance, sleeve friction and water pressure are commonly measured parameters. Includes static and dynamic cone penetration tests.
conventional core original
notation 4.1.1
broader
diamond core original
definition Core drilling using a diamond or tungsten carbide bit and a core barrel with fibreglass inner sleeves. To retrieve the core samples, the complete rod string and core barrel assembly has to be removed from the hole. Conventional coring is much more time consuming than wireline coring, as each rod has to be removed from the hole individually, then lowered back into the hole to continue to advance the boring and collect the next core sample. Used in the oil industry.
core drilling original
notation 4
definition A core of sediment, soil, or rock is derived by an unspecified core drilling method.
narrower
diamond core original
direct push original
vibrocore original
Delft sampler original
notation 4.2.1
broader
direct push original
definition The Delft continuous sampler, developed by GeoDelft, is used for obtaining high quality samples within very soft cohesive soils. The sampling system is available in two sizes to take continuous samples, 29 or 66mm in diameter, normally with a maximum penetration of about 18m. A steel outer tube is pushed into the ground using standard CPT (cone penetrometer test) equipment and the soil sample core is fed into a thin-walled plastic inner tube as the sampler advances. After extraction, the samples are cut into 1 m lengths and placed in purpose-made cases, being retained in the plastic tubes.
diamond core original
notation 4.1
broader
core drilling original
definition Diamond core drilling (or diamond drilling) utilizes an annular diamond- or tungsten-carbide-impregnated drill bit attached to the end of hollow drill rods to cut a cylindrical core of solid rock. The diamonds used are fine to microfine industrial grade diamonds. They are set within a matrix of varying hardness, from brass to high-grade steel. Matrix hardness, diamond size and dosing can be varied according to the rock which must be cut. Holes within the bit allow water to be delivered to the cutting face. This provides three essential functions: lubrication, cooling, and removal of drill cuttings from the hole. Core samples are retrieved via the use of a core tube, a hollow tube placed inside the rod string and pumped with water until it locks into the core barrel. As the core is drilled, the core barrel slides over the core as it is cut. An "overshot" attached to the end of the winch cable is lowered inside the rod string and locks on to the backend (aka head assembly), located on the top end of the core barrel. The winch is retracted, pulling the core tube to the surface. The core does not drop out of the inside of the core tube when lifted because either a split ring core lifter or basket retainer allow the core to move into, but not back out of the tube.
narrower
conventional core original