Improved fragmentation results in higher productivity for Newcrest
Document type: Case Study

Improved Fragmentation Results in Higher
 Productivity for Newcrest

Project Summary
BLASTING 150M UP-HOLES TO IMPROVE INITIAL
CAVING DYNAMICS
When Newcrest approached Dyno Nobel with the idea of
blasting a 150m long vertical up-hole, the enormity of the
project was quickly realised. Conventional loading
techniques and products were not suitable for such an
undertaking. So a period of design and innovation ensued. During this development period, specifically designed
products such as TITAN® BPC, custom made SmartShot®
detonators and innovative pumping solutions were devised,
put into action and rigorously tested. The project scope was very specific, with the requirement
for an explosive that can maintain sensitivity and have a The mining method employed at the site is Panel Caving
constant density throughout the blast hole being a critical which is a natural caving method that uses ground stresses,
component. Meeting these requirements, combined with rock structures and gravity to break the rock. The Cadia
having control over communication with the initiation East mine is the first panel cave in Australia and the
system and blast timing, meant that the Blast deepest panel cave in the world with the extraction level
Preconditioning (BPC) holes could be blasted safely. lying approximately 1,200m below the ground surface.

d blast timing, meant that the Blast deepest panel cave in the world with the extraction level
Preconditioning (BPC) holes could be blasted safely. lying approximately 1,200m below the ground surface. Ore
 is extracted using a mechanised fleet and delivered to the
This culminated in the successful firing of a single trial hole
 surface through an underground conveying system for
containing almost 3,300kg of explosive in June 2011. processing. Following almost 18 months of planning, multiple pumping
and blasting trials, the first BPC production blast of two
holes was fired successfully on the undercut level in Project Goals
October 2011. Multiple holes have been fired
 IMPROVING ADVANCE AND PRODUCTIVITY
instantaneously since that time. WHILST MINIMISING DAMAGE
 Background Panel and Block Caving operations can experience periods
 of low cave advance and poor productivity when caving is
AUSTRALIA’S LARGEST GOLD PRODUCER HAS initiated due to limited time for in-situ crushing resulting in
SOME UNIQUE CHALLENGES sub optimal fragmentation. Blast Preconditioning of the
 Block Cave is designed to engineer the rock mass to
Newcrest’s Cadia Valley Operations are located
 produce material of a suitable block size and assist in the
approximately 250 kilometres west of Sydney and
 initial propagation of the cave. approximately 20 kilometres from the regional centre of
Orange.

ce material of a suitable block size and assist in the
approximately 250 kilometres west of Sydney and
 initial propagation of the cave. approximately 20 kilometres from the regional centre of
Orange. Newcrest is Australia’s largest gold producer and Protecting mine infrastructure was also of great importance. one the world’s top 5 gold miners. The Cadia East Given that the Blast Preconditioning holes were fired prior
resource, located adjacent to the Cadia Hill open pit, is a to blasting the undercut level, minimising damage to the
massive low grade gold-copper porphyry deposit covered drives was paramount. Consequently, all blasts had to be
by up to 200m of overburden. The system is up to 600m loaded and fired with minimal deviation from design. wide and extends to 1.9km below the surface.

Improved Fragmentation Results in Higher
 Productivity for Newcrest

Technology Applied
DEVELOPMENT OF TITAN BPC AND A PROCESS TO
LOAD AND FIRE
For Newcrest’s panel cave project to be a success it was
vital for Dyno Nobel to develop a new explosive and
delivery system that would be capable of loading such
holes. being initiated without issue – sometimes numerous days
A specifically designed emulsion based explosive, Titan
 after being loaded. BPC, was developed for this application. The requirements
of the explosive were for it to be robust, easy to handle,
able to maintain sensitivity when exposed to high head Value Added
pressures and have a high Velocity of Detonation (VoD). Prior to the use of Titan BPC underground, these IMPROVED FRAGMENTATION RESULTING IN
characteristics were proven in open pit trials. HIGHER PRODUCTIVITY
In order to combat the high head pressures associated with Firing the BPC holes fully confined produces significant
a 150m high column of explosive, re-engineering of the fracturing in the rock mass adjacent to the blast hole. These
delivery system was a prerequisite. The Dyno Nobel fractures assist in the comminution of the rock mass,
Engineering and Operatons teams worked closely to devise improving caving dynamics particularly at the
a new design. Following a series of trials, a modified commencement of the caving process.

mass,
Engineering and Operatons teams worked closely to devise improving caving dynamics particularly at the
a new design. Following a series of trials, a modified commencement of the caving process. The finer
Mobile Processing Unit (MPU) was shown to be capable of fragmentation of the ore body from the BPC process should
consistently loading Titan BPC into a 150 metre long up- result in decreased down time of the drawpoints which in
hole. turn could increase production rates, and ultimately assist
Having almost 3,300kg of Titan BPC in the hole with a 20m to ensure that cave propagation meets or exceeds the
grout plug at the collar meant that a reliable and robust customer’s expectations. initiation system was required. Damage from blasting to backs and drives has been
Custom made SmartShot detonators were manufactured to minimal. Accordingly, the requirement for ground support
ensure accurate initiation together with the benefit of 2-way re-work has decreased and there were safe working
communication to determine the detonator status in-hole. conditions on the undercut level directly below where the
Lead lengths of up to 160 metres were employed to reach BPC holes have been fired. the toe of the hole. The SmartShot system performed Continued, close collaboration with Newcrest ensured that
extremely well in tough conditions with the detonators this project was a success.

fired. the toe of the hole. The SmartShot system performed Continued, close collaboration with Newcrest ensured that
extremely well in tough conditions with the detonators this project was a success. Today, groups of four BPC
surviving intense pressures (up to 30 bar) in the hole and blast holes are fired together, with this occurring several
 times per month.

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