Explosives Today 3

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Explosives Today Series 4 No 3 Detonating cord as a down line with Pentolite boosters Detonating cord as a down line with Pentolite boosters This method of priming a blast hole is used very effectively in hot hole conditions. Hot holes are normally encountered in the surface coal mining industry where previously mined coal seams (that are burning), are being mined from surface. This prevents the use of conventional detonators, and a Pentolite booster and detonating cord provides the solution. Once the cord has been laced through the booster, the tail end should be knotted to prevent the cord pulling out of the booster when charging of the hole takes place. The example shown on the far left is Powercord 8 in combination with a 150g Pentolite booster. The other sample shown is Powercord 8 Premium in combination with a 400g Pentolite booster shell. ENVIRONMENTAL CONCERNS It is important to remember that detonating cord can have negative impacts on the surrounding environment. Airblast is the most significant of these, especially when working with detonating cord in close proximity to built-up areas. Always ensure that when using detonating cord under these circumstances that measures are put in place to limit the impact on the environment. This could include covering of the detonating lines with mats and loose sand. DESTRUCTION OF DETONATING CORD Detonating cord should only be destroyed by burning. Never attempt to destroy detonating cord while it is still wound onto its reel or spool. At the burning area, the detonating cord is first unreeled and inspected for any knots, splices and aluminium caps which must be removed and burned separately. It is then cut into 1 metre lengths, weighed and placed in bags of not more than 5kg. Place the individual 5kg batches in single piles 3m apart as per markers. Do not exceed the license.

This document replaces all previous Explosives Today on this subject including Series 2. No 29: September 1982 (J L Miller)

Safe use of detonating cord in Surface Mining applications Ken Meiring, Senior Explosives Engineer

Detonating cord comprises of a continuous core of high explosive water resistant pentaerythritol tetranitrate (PETN), held in a plastic sheath and wrapped in yarns with a waterproof overcoat. It detonates at a very high velocity (>6000m/s) and will initiate any sufficiently sensitive explosives charge with which it is in contact.

Wealth Unearthed

Disclaimer: Any advice and/or recommendations given by AEL Mining Services Limited (“AEL”) in this publication, is given by AEL in good faith in order to provide assistance to the reader. AEL does not however: 1.1 warrant the correctness of its advice and/or recommendations; 1.2 warrant that particular results or effects will be achieved if AEL’s advice and/or recommendations are implemented; 1.3 accept liability for any losses or damages that may be suffered, as a result of a party acting, or failing to act, on the advice and/or recommendations given by AEL; 1.4 accept liability for any acts or omissions of its employees. representatives and/or agents, whether negligent or otherwise. Copyright: All copyright that subsists in this publication together with any and all diagrams and annexures contained herein, which shall include all and/or any ideas, plans, models and/or intellectual property contained in this document vests in AEL. Any unauthorised reproduction, adaptation, alteration, translation, publication, distribution or dissemination (including, but not limited to, broadcasting and causing the work to be transmitted in a diffusion service) of the whole or any part of this document in any manner, form or medium (including, but not limited to, electronic, oral, aural, visual and tactile media) whatsoever, will constitute an act of copyright infringement in terms of the Copyright Act No.98 of 1978 and will render the transgressor liable to civil action and may in certain circumstances render the transgressor liable to criminal prosecution. This document remains the intellectual property of AEL. Intellectual Property: All ideas, concepts, know-how and designs forming part of this publication belong to AEL, save for where it is clearly indicated to the contrary.

AEL Mining Services Limited (PTY) Ltd 1 Platinum Drive, Longmeadow Business Estate North Modderfontein, 1645 Tel: +27 11 606 0000 www.aelminingservices.com

The AEL detonating cord range is supplied under the trade name of Powercord®, with three standard products, namely Powercord 6, Powercord 8 and Powercord 10 and one premium product, Powercord 8 Premium. These cords are distinguished from each other by their colour and the mass of their core load, as follows:

Product

Colour

Core load

Benefits

Features

Powercord 6

Orange

6 g/m

Powercord 8

Blue

8 g/m

• •

Powercord 10

Yellow

10 g/m

Powercord 8 Premium

Red with black stripe

8 g/m

• • • •

Relatively insensitive to detonation by heat, electrostatic discharge or other forms of electricity Excellent resistance to side penetration by oil or water High tensile strength Easy to handle and tie into knots Flexible High packing density of PETN core (Premium only)

• •

VOD≥6000m/s Reliably initiated with 6D strength detonator Easy to connect branch lines Easy to initiate and can be extended with knots Can be used in very wet conditions (Premium only)


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