Abstract
HMX Based Electronic Initiation System for Blasting in High Temperature Ground and/or Extremely Reactive Ground
Phase 2 – Blasting Campaign in Western USA
Karl Dufresne, Market Development Manager, DynaEnergetics Europe GmbH
Troisdorf, Germany
Abstract
Blasting in geothermally high temperature ground and/or extremely reactive ground is an increasing common challenge for surface and underground mines.
Many current PETN based non-electric and electronic detonators have manufacturer published in-hole temperature limits ranging from 55°C to 65°C (131°F to 150°F). When confronting blasthole temperatures above the manufacturer published limits, operations may request site-specific guidance and qualification for use. The advised safe loading window for in-hole PETN based detonators is often too short to be practicable for production blasting.
To overcome limitations of PETN based initiation systems, surface mines with high temperature ground and/or reactive ground are known to load blastholes with a qualified high temperature bulk emulsion that are top primed with a cartridge of temperature qualified detonator sensitive emulsion plus an RDX detonating cord downline. As there is no in-hole delay detonator in this system, blasthole timing is accomplished with surface delays. Although this system is safe, top priming and surface delaying does influence floor quality and top size fragmentation, and safe loading windows times reduce blast block size and increase blasting frequency.
A mining company with a site characterized by geothermally high temperature ground plus highly reactive ground employed a blasting system like the one described above. At the request of the mining house, DynaEnergetics developed an electronic initiation system for application in geothermally high temperature ground and/or extremely reactive ground conditions.
The DynaEnergetics IGNEO high temperature electronic initiation system is rated for in-hole use in ground up to 150C (302°F) for 48 hours. The detonator consists of a high strength detonator with an HMX base charge and thermally resistant downline. To make up a primer, the detonator is inserted into a booster charge assembly that is fitted with a small HMX shape charge. This high energy primer is designed to be compatible and reliable for firing bulk emulsions, including those with high percentages of urea inhibition to combat reactive ground. The system is controlled by a digital firing panel that can be used with either a wired or wireless trigger.
The system enables high temperature and/or reactive ground sites to utilize in-hole delay initiation and realize the associated performance benefits.
Western USA
An underground mine in Western USA has several areas in their development heading with very high temperature, in view of this, they decided to use the IGNEO detonators to evaluate the effectiveness and performance of the system.
The first blast took place on Aril 17 and the in-hole temperature average were between 170- and 270-degree F.
Subsequent blasts were delayed due to an unforeseen event that delayed the campaign. The mine is working on rehabilitating the area. They should resume blasting in Q1 of 2025.