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DTH drilling
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DTH
A Down-The-Hole Drill is called DTH in most drilling terms.
The down-the-hole drill is basically a mini jack hammer that screws on the bottom of a drill string.
The fast hammer action breaks hard rock into small flakes and dust and is blown clear by the air exhaust from the DTH hammer.
The DTH hammer is one of the fastest ways to drill hard rock.
It is rotary cum percussive type drilling.
DTH
DTH is short for “Down-The-Hole”.Since the DTH method was originally
developed to drill large-diameter holes downwards in surface-drilling applications.
its name originated from the fact that the percussion mechanism followed the bit down into the hole.
Applications were later found for the DTH method underground.
The direction of drilling is generally upwards instead of downwards
Working of DTH
In DTH drilling, the percussion mechanism commonly called the hammer is located directly behind the drill bit.
The drill pipes transmit the necessary feed force and rotation to hammer and bit plus compressed air or fluids for the hammer and flushing of cuttings.
The drill pipes are added to the drill string successively behind the hammer as the hole gets deeper.
The piston strikes the impact surface of the bit directly, while the hammer casing gives straight and stable guidance of the drill bit.
Working of DTH
The impact energy therefore is not lost in joints allowing for much deeper percussion drilling.
This means that the impact energy does not have to pass through any joints at all.
This is a Great break through for smaller portable water well drilling rigs, that before were limited.
The DTH on smaller rigs now can get same results as large heavy truck rigs.
DTH drilling
4500 meter
By DTH we can drill up to
Uses of DTH
Mining- Drill & Blast holes in Open Pit mining, Where the drill operator will drill several holes.
Then fill with explosives and detonate to lift rock allowing access to ore body RC- Exploration & Pit grade control GW- Geothermal Bore Holes & Water wells Oil & Gas- Deep well Bore Holes Construction- Piling, Footings.
DTH drilling is used in the construction industry to produce piles into rock, also water wells, and drilling bores for geothermal ground source heat pumps.
DTH Drilling Tool
Comparison
Comparison
Comparison
Parameters DTH Hammer Drilling(cost/hour)(40 m)
Rotary Drilling(cost/hour)(24 m)
Depreciation Rs. 1772 Rs. 1441
Repairing Rs. 1000 Rs. 785
Hammer Rs. 993 Rs.-----------------
Drill Bits Rs. 292.72 Rs. 397.00
Drill Tubes Rs. 330.84 Rs. 74.5
Dust collection Rs. 62.03 Rs. 62.03
Labour Rs. 537.62 Rs. 537.62
Fuel Rs. 893.27 Rs. 635.22
lubricants Rs. 181.96 Rs. 165.42
Total cost Rs. 6064 Rs. 4098
Cost/meter Rs. 151.6 Rs. 170.75
