Percussion Drilling

percussion drilling

[pər′kəsh·ən ‚dril·iŋ]
(mechanical engineering)
A drilling method in which hammer blows are transmitted by the drill rods to the drill bit.

Percussion Drilling


the process of drilling blastholes and boreholes by percussive destruction of rock with a boring tool whose working cutters are usually wedge-shaped.

Cable-tool percussion drilling of vertical blastholes and exploratory, hydrogeological, and ventilation wells 150–600 mm in diameter to depths of 20–500 m and more is done with drillrigs that use a cutter weighing 0.5–3.0 tons. The cutter delivers 40–60 blows per minute to the face. Percussion-rotary drilling of blast-holes 36–85 mm in diameter is done using hammer drills with dependent (discontinuous) rotation of the bit, striking 1,800–2,000 blows per minute with an axial force of 0.5–1.2 kilonewtons (kN), or 50–120 kilograms-force (kgf). Rotary-air-percussion drilling of blastholes and boreholes is done using hammer drills with independent rotation of a bit 36–85 mm in diameter and bottom-hole pneumatic strikers (seePNEUMATIC PERCUSSION DRILLING). The tool rotates at 20–75 rpm and has a specific striking force of 10–25 joules per cm (J/cm) of diameter and an axial forward force of 1–3 kN (100–300 kgf). Rotary-percussion drilling of blastholes is done by special machines mounted on frames; the machines rotate at 100–150 rpm, delivering 1,500–4,000 blows per minute, with a specific striking force of 5–20 J/cm of diameter and an axial force of 10–15 kN (1,000–1,500 kgf). Hydraulic percussion machines and bottom-hole hydraulic strikers are also used. Electric hammer drills are being developed (1977).


References in periodicals archive ?
Ranger Drilling Services has been awarded a percussion drilling contract for all reverse circulation (RC) and aircore drilling services.
Drilling has been limited to percussion drilling in the 1980s, with anomalous values of gold up to 1.
HammerHead Trenchless Equipment has introduced the HammerHead Roughneck R600, the largest of its pneumatic percussion drilling systems for use in horizontal directional drilling applications.
The programs were a mixture of reverse circulation (RC) percussion drilling and diamond core drilling, targeting upgrades at THW and new mineralised areas at THE.
In 2011, a total of 13,630 m (52 holes) of diamond drilling and 2,940 m (21 holes) of reverse circulation percussion drilling was completed on the Klaza property.
The company has completed 358 metres of percussion drilling in 32 holes on the mineralised Macalder tailings and these are being prepared for multi-element and metallurgical testing.
The most common methods are mud and air rotary drilling and down-hole hammer or percussion drilling.
These confined gases take the path of least resistance -- the micro fractures created during the percussion drilling in the surrounding rock.
The initial results of percussion drilling rates confirmed the speed rate was ten times faster, when compared to trepanning.
These UV lasers do not have the pulse energy or frequency to utilize percussion drilling for greater productivity.
The JV partners have committed to the rapid evaluation of the prospect, which to date has included surface rockchip sampling; evaluation RC percussion drilling programs, aeromagnetic interpretation and a detailed geological mapping - all with positive results.
Whether a customer chooses rotary or percussion drilling, it's important for them to understand and know how to determine the right compressed-air volume and pressure for the selected drilling application, explained Karl Ingmarsson, vice president of marketing for Sandvik Mining & Construction.