HV HV3 NV NV3 PV PV3 Conventional Diamond Core Barrel for exploration drilling
Conventional Diamond Core Drilling
Conventional Core Barrel Complete
Conventional core barrel 1.5 meter , Conventional core barrel 3.0 meters
Conventional core barrel 5 ft / 10 ft 1.5 meters / 3.0 meters for exploration core drilling
Conventional Diamond Core Drilling Conventional core barrel 5 ft / 10 ft for exploration core drilling
Conventional Diamond Core Drilling HV HV3 NV NV3 PV PV3 Conventional Core Barrel Complete for exploration core drilling
Conventional Diamond Core Drilling
ROSCHEN have the capability to carry out diamond core drilling in various diameters - to depths up to 450m.
NLMC = 47.6mm diameter core, resulting in a 75.7mm diameter holes.
HQ = 63.5mm diameter core, resulting in a 96mm diameter hole
4C (Equivalent to PQ) = 85mm diameter core, resulting in 122.6mm diameter hole.
Core drilling is different to other drilling techniques in that a solid core of rock rather than cuttings is extracted from the hole. The diamond drill bit comprises a short steel shank with a cutting head using natural ("surface set") or man-made ("impregnated") diamonds as the cutting medium. In softer sedimentary formations and often coal, other cutting elements are used such as tungsten-carbide and polycrystalline diamond compacts (PCD). Water is the usual circulation fluid used to remove the cuttings and cool the drill bit.
As the drill bit advances, a cylindrical core of rock progressively fills a triple tube core barrel (double tube barrels are also used by some companies) immediately above the core bit. Core samples are periodically recovered, (ROSCHEN use 3.0m long core barrels,) at the end of the core "run" the complete barrel and the drill rods are pulled from the hole, the end of the barrel is disassembled by removing the core bit and catcher, the the stainless steel splits are then pumped out of the inner barrel by using high pressure water. The splits are then opened to reveal the core in virtually undisturbed condition.
Rotation speeds during diamond core drilling can vary from 150 to 400rpm for surface set bits, to more than 1500 rpm for impregnated bits. Penetration rates are much slower than other methods generally due to the hardness and at times the weakness of the rock, plus the time taken to retrieve the core barrel when drilling at deeper depths. An alternative to Conventional core drilling is wireline core drilling this can speed the drilling progress up especially when drilling deeper holes -
Wireline Core Drilling
ROSCHEN also have the capability to carry out wireline core drilling.
Wireline core drilling is the same principle as conventional core drilling whereby a solid core of rock is collected within the core barrel, the difference is how the core barrel is retrieved from the borehole. When the core barrel is full or the run is finished instead of the complete drill string - rods and core barrel being pulled from the hole, the core rods and outer core barrel remain in the hole and only the inner core barrel is retrieved by lowering a cable with an overshot down the core rods. The overshot attaches to the top of the inner tube/barrel of the core barrel and then the assembly is winched to the surface. The inner barrel is disassembled and the core pumped from the inner barrel as is done in conventional core drilling.
Wireline core drilling requires a completely different set of gear - bits, rods and associated tooling to that used for conventional core drilling which is not generally carried with the rigs at all times - please let your ROSCHEN contact know if you require wireline core drilling prior to mobilisation to site.
DCDMA sizes B, N, H, and P.
T2 56mm, T2 66mm, T2 76mm, T2 86mm, T2 89mm, T2 101mm, T2 116mm, T2 130mm
AQ, BQ, NQ, HQ, PQ/ BQ3, NQ2, NQ3, NQTT, HQ3, HQTT, PQ3, PQTT, T2 46, T2 56, T2 66, T2 76, T2 86, T2 101, T6 86, T6 101, T6 116, T6 131
NMLC, HMLC, LTK48, LTK60, BGM, NGM, ADBG, TBW, TNW, ATW, BTW, NTW, NXD3, AX, NX, NXC, AXT, T6H, 4 9/16, NWD4, 412F, SK6L146, TT46, TB56, TS116, CHD101,
AW, BW, HW, NW, PW, SW, ZW