New Drilling Tools for Hard Rock Nordic Geotechnical Meeting 2012, Copenhagen

Transcription

1 Nordic Geotechnical Meeting 2012, Copenhagen Gordian Ulrich Product Management

2 Nordic Geotechnical Meeting 2012, Copenhagen 1. Commonly used tools for rock 2. Introduction of the Multi Hammer Tool (MHD) 3. Capabilities 4. Case studies

3 Rock Drilling - Kelly Mode (Rotary Drilling) Suitability of conventional tools Unconfined Compressive Strength UCS [MPa] Rock Auger Core Barrel Roller Bit Full Face Cutter

4 MHD Cutting edge technique for rock Limitations - example Singapore (1000 mm down to 30 m) Drilled 5 h with core barrel for 1,8 m (=0,36 m/h) Granite boulders Worn out round shank chisels.

5 Commonly used tools Weak points: Percussion? Performance? Grab Chisel Casing Oscillator

6 Challenges in the subsoil 0 m 3 m 10 m 23 m Fill Boulders 100 MPa Sand and boulders Granite 250 MPa Typical project Diameter 1500 mm Boulders from 3 to 23 m Rock socketing in Granite Options Conventional tools? No Roller bit tools? No Chisel? Very time consuming Solution Multi single down the hole hammer

7 Multi Hammer Drill Standard Kelly bar Ratchet attachment with Kelly box Calyx basket Canister with several hammer Bit

8 Multi Hammer Drill +/- 360 Chippings get flushed upwards Advantage: No Air swivel required! View into Calyx Basket

9 Multi Hammer Drill Calyx Basket Chipping area Canister with Hammers

10 Multi Hammer Drill - Movie Klick picture for movie

11 Multi Hammer Drill How much crowd force is required? Weight on bottom Advantages: No big drilling rigs are required Little torque is sufficent

12 MHD Cutting edge technique for rock Limitations Yes, it is possible to drill dipping rock surfaces These 2 do not exhaust the air MHD Only this one is working casing G-3 technology required MHD does not require high crowd force Start with little crowd force until bottom is flattened Good indicator is the air pressure Dipping rock

13 Multi Hammer Drill What about wear and tear - maintenance? Bit and chuck Lifetime depending on rock condition and operator - Minimum footage 40 m (Granite high silica content) - Up to 200 m (Sandstone, Limestone) Keep up with hardfacing the canister Hammer Lifetime depending on rock condition and maintenance - Average 200 working hours - Can be overhauled (sealing kit available) Periodically inspect hex openings

14 Multi Hammer Drill Case Study Foundation Overlapping secant pile wall No. of piles 135 Diameter 1180 mm Depth 25 m Casing Fully cased to 18 m Rock socket Rock hardness Performance MHD Wear and tear 7 m in Sandstone and some slate MPa Sandstone MPa Slate 7 m rock drilling in 2 h 20 min (3 m/h) including emptying calyx basket maintanence after 120 m rock driling exchanged bits and chucks, hammer were rebuilt They tried doing secondaries with rock auger on BG 40. And got 1,20 m in 2 hours (0,6 m/h).

15 MHD Cutting edge technique for rock Project references Case Foundation in the US Secant Pile Wall Rock Socket length Diameter 25 m deep 7 m Granite 1180 mm Estimated Actual progress 1,2 m/h = day and night shift 2,7 m/h Eliminated all second shift drilling and stayed on pre-planned schedule

16 MHD Cutting edge technique for rock Sizes and Air consumption Full Face MHD Air consumption Each hammer needs 11 m³/min at 11 bar

17 Multi Hammer Drill 1. Can be attached to Kelly bar (no drill pipes required) 2. Performance 3 to 5 times higher compared to conventional tools 3. No impact into the rotary drive or Kelly bar 4. Boulders any size can be drilled 5. Rock up to 300 MPa and above 6. Uniform hammer and bits for every diameter easy handling 7. Economical bit costs

18 Most famous reference Chile miners trapped in 620 m depth, Center Rock drilled them out in 33 days 33 men trapped

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