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DSI New Developments in Yieldable Rock Bolts

2012 Dynamic Ground Support Application Symposium Thursday, September 13th, 2012

Renn Oler, Engineering DirectorDywidag Systems International (DSI) Underground Sys Inc.

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DSI Ground Support, Inc.Dynatork Bolt OverviewDesign CriteriaDynamic TestingStatic TestingConclusion

DSI Underground Systems

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DSI Underground Systems

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DSI Mining & Tunneling Locations

America Europe

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DSI Underground Systems

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ISO 9001/2000

DSI is committed to:Meeting our customers needsBeing innovative, efficient, quality- and safety-conscious Continuously improving our processes, products and services, and the skills of our employees

Certified according to ISO 9001/2000 since 1994

Highest quality standard from development to application

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83 basic patents193 patents registered worldwide

88 basic patents268 patents registered worldwide

DSI Patents

CONSTRUCTIONPost-Tensioning & GeotechnicsConcrete Accessories

UNDERGROUNDMining & Tunneling

Status: 2009-03

DSI Dynatork Bolt– Overview

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Patent Pending

The purpose of the dynamic bolt is to transfer the dynamic load of a rock burst into the support system through the resin to rock interface.

DSI Dynatork Bolt – Design Criteria

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Overcome the following market limitations:

• Thoroughly Mixing the Resin• Reduce Costs to the Mines• Decrease Quality Failures by limiting process and

excess components• Withstand up to 30kJ of impact energy with limited

deflection• Exceed the industry limit of 3 impacts

DSI – Design Criteria

• Thorough resin mixing helix, patented design• Advanced resin mix and anchoring

ability • Controlled mix• Design utilizes the coefficient of

friction versus the requirement of controlling the friction with a coating.

• Reduce Costs to the Mines• Simple manufacturing method

• 2 components, one step process• Limiting Defects

• Simplistic Design

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DSI – Testing

Testing conducted at the CANMET facility.

• 1.5 – 2.5 tons dropped onto a plate

• drop height 1.5m • Height to Mass ratio

• Hole size of 31mm -34mm

• Drop weight of 1115 kg –2006 kg

pre and post impact

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DSI – Impact Results

Energy# of

ImpactsAverage

DisplacementAverage

Load

16.41 kJ +5 138 mm - 226 mm 7 - 13 tons

22.96 kJ 4 242 mm -300 mm 8 -12 tons

30 kJ 2 208 mm – 379 mm 12 -22 tons

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Visual Summary of Displacement

Dynamic Results

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impact test result at 22.97 kJ (drop 2)

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Holding Force of 11 tons – 17 tons

Static Results

DSI Dynatork Bolt – Dynamic Yielding Solution

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Dynamic Bolt Energy Absorption  15 kJ Tested 23 kJ Tested 30 kJ tested

1055 Modified SteelElongation 10%

Yield Strength 560 MPa 81,200 psiUltimate Tensile Strength 660 MPa 65,700 psiWasher Plate Dimensions 6 in x 6 in x ¼ in  7/16 in ‐ 1 in dome

Washer Plate Yield Strength 160 kN 36,000 psiSmooth Bar Diameter 19.05 mm 3/4 in

Hemispherical Pinnut (dia x len x hole dim) 46 mm x 18 mm x 19 mm

1055 Modified

Smooth Bar

Technologically Advanced – PatentedUnique Mixing Helix

Dome Plate