Development optimisation leads to reduced overbreak and cycle efficiencies
Document type: Case Study

Development Optimisation Leads to
 Reduced Overbreak and Cycle Efficiencies

practices that will deliver benefits whilst ensuring zero harm
 Project Summary to personnel.

Dyno Nobel understood market expectations and recognised
Dyno Nobel and Glencore Xstrata’s George Fisher Mine
 that tangible benefits could be achieved through optimisation
successfully completed a series of development optimisation
 of the development cycle. As a result, a proposal was put
trials where the various elements of drill and blast were
 forward for a development optimisation project.
evaluated in order to establish standards to optimise the
development cycle.
 Project Goals
The elements optimised included perimeter charging, drill
and charge designs utilising bulk emulsion and the use of
precision timing in both perimeter only and full face
development headings.

The trials were conducted in a controlled environment with
each introduced element measured and validated against
captured benchmark practices. Benefits of the optimisation
trial included:
 A 12% saving in direct development costs;
 A 13% reduction in the development cycle time;
 Increased productivity to the development schedule;
 Improved standard in drilling practices.

Background
 The objectives of the project were to:
  Measure and establish a benchmark for current practice;
The George Fisher Mine is situated approximately 25km  Improve the profile integrity and smoothness of backs
north of Mt Isa, it is an underground silver, lead and zinc and walls (half barrel markings) through optimised
operation wholly owned by Glencore Xstrata PLC producing charging and the use of precision initiation;
in excess of 3Mtpa.  Develop a standardised drill design with reduced drill
 holes;
The mine is divided into two separate mining areas, being  Improve blast fragmentation and muckpile positioning
George Fisher North and George Fisher South. Both mining through the flexibility and consistency of precision timing;
areas have dedicated development schedules with a North:  Reduce the costs and cycle times associated with the
South split of 66:34 for the scheduled development metres elements of development mining;
for 2013/14.
  Establish a standard of best practice.

During the last decade, mine sustainability has been
 The plan involved introducing changes to the key elements
impacted by lower ore grades, increased costs in overheads
 in a controlled manner (one change at a time) to evaluate
and consumables, and capital requirements in an
 performance and quantify the benefit of each change against
environment of global financial unrest and volatile metal
 the benchmark.
prices.
 Validation of the changes to various elements in order to
To ensure competitiveness and sustainability in today’s
 optimise development practices was achieved by direct
challenging environment, miners must look to decrease their
 measurement, comparisons against the baseline, digital &
development costs per meter through improved mining
 photogrammetry imaging, cost analysis and operator
 feedback.

Development Optimisation Leads to
 Reduced Overbreak and Cycle Efficiencies

 A standardised drill design used by all jumbo operators
 Technology Applied across all profiles incorporating at least a 9% reduction in
 face holes. The timing flexibility of electronic detonators
 provided the ability to optimise blast hole interaction
Optimal charge designs were achieved in practice using the which allowed for the removal of drill design redundancy;
 ®
DynoMiner™ Profile to deliver TITAN 7000i bulk emulsion  Reduced explosive usage per face by 30%;
utilising string loading capabilities (decoupled charge) for  Butts reduced from 400mm average to 50mm average;
improved perimeter control as well as adjustable density to
  Qualitative feedback indicates reduced scaling and
suit ground conditions. The use of bulk emulsion also
 ground support cycle, together with improved
eliminated traditional manual handling issues associated with
 fragmentation (average 150mm) with a reduction in the
the use of specialised perimeter products. mucking cycle;
  A 12% saving in direct development costs;
The application of Dyno Nobel’s electronic detonators was a
  Decrease in cycle times of 13% resulting in an increase
major enabler of the development optimisation process. The
 in development productivity.

lication of Dyno Nobel’s electronic detonators was a
  Decrease in cycle times of 13% resulting in an increase
major enabler of the development optimisation process. The
 in development productivity. precision timing of the detonators has mitigated “delay
scatter”, while the combination of timing flexibility and
accuracy has resulted in consistent and repeatable blasting
outcomes.

Remote initiation of development headings from the surface
was achieved with a Blast Control Unit (BCU) which
eliminates any potential risk to personnel during firing times
and greatly improves firing reliability.

Photogrammetry analysis was used to capture 3D images
from which volumes of post fired faces can be calculated to
determine under/overbreak and confirm the benefits of the
introduced optimised elements.

Value Added
HEADING

Value added benefits realised from the optimisation project The ability to remain sustainable in the face of adversity and
include: reap the benefits of improved margins in favourable markets
 Safety improvements in the charging process through the is dependent on reducing the cost per metre of development.
 use of bulk emulsion, eliminating manual handling issues To that end, establishing standards from optimising the
 associated with cartridged products; various elements of drill and blast in development mining will
 Improved quality and integrity of the perimeter profile as assist to ensure best practice and optimal cost position.
 evidenced by the half barrels post blasting;
 Overbreak reduced from 25% to 5% due in part to firing
 all perimeter holes at the precisely the same time which
 creates a smooth profile and reduces radial crack
 damage outside the perimeter;

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