Improved digability, reduced vibration in Truck Shovel operation
Document type: Case Study

Improved Digability, Reduced Vibration in
 Truck Shovel Operation

Project Summary Project Goals
REDUCED VIBRATION ALLOWS MINE TO DEVELOPING A TECHNIQUE THAT WOULD
DISREGARD SCALED DISTANCE LIMITATIONS ALLOW FOR MINIMIZING THE USE OF DECKED
The close proximity of both power lines and railroad tracks HOLES WHILE MAINTAINING VIBRATION
caused this mine to adopt blast designs that did not result WITHIN DESIRED LIMITS
in optimum digging rates for shovels. Use of scaled
 The decision was made to shoot a series of single hole
distance calculations required multiple decking that did
 test shots and utilize SHA in an effort to determine optimal
nothing to aid in digability while having marginal impact
 firing times for future blasts. The goal was to develop blast
on vibration at key structures. The use of SHA (Signature
 designs and timing scenarios that minimized or eliminated
Hole Analysis) and electronic detonators allowed the mine
 the need for decked holes, allowed for exceeding the
to dial in optimum timing sequences regardless of the
 modified scaled distance charge weight limit and resulted
number of holes per delay, resulting in reduced vibration
 in recorded peak particle velocity values well within the
and better digging rates allowing for faster removal of
 5.0 ips restriction in place for both the railroad tracks and
overburden.
 the power transmission poles.

Background
 S Technology Applied
PIT ADVANCE REQUIRED CHANGES IN BLAST
DESIGN VIBRATION CONTROL SOFTWARE EMPLOYED
The advance of this coal pit has moved steadily toward TO DETERMINE OPTIMUM FIRING TIMES TO BE
the rail loop that serves the mine. In addition, power USED WITH DIGISHOT® ELECTRONIC
transmission lines run parallel to the railroad tracks. Both DETONATORS
the railroad tracks and the power transmission lines have A series of single hole blasts was recorded by an array of
imposed vibration limits based on either seismic seismic units. Data from these seismographs, deployed
monitoring or the use of a modified scaled distance at key locations along the power transmission line right-
formula approved by the state regulatory agency. of-way, was processed and used with the Dyno 42
As the pit advanced, decking became necessary in order vibration control software program. Optimum firing times
to maintain charge weights that met the modified scaled were calculated on a shot by shot basis to determine the
distance factor. While seismic monitoring was performed best delay sequence to create destructive interference
for most shots, blast designs were still based on scaled between transient vibration waves radiating from each
distance. hole.

ring was performed best delay sequence to create destructive interference
for most shots, blast designs were still based on scaled between transient vibration waves radiating from each
distance. hole. Multiple decking resulted in increased loading times as Selected firing times were integrated into the blast
well as increased costs for accessories. Decking also through the use of both DigiShot programmable electronic
required a reduced burden and spacing in order to detonators and NONEL® nonelectric detonators. The use
maintain the desired powder factor. This added of derived timing sequences allowed for exceeding the
significantly to the cost of drilling per unit volume of calculated modified scaled distance charge weight limit
overburden. without risk of exceeding the vibration criteria for the key
 structures.

Improved Digability, Reduced Vibration in
 Truck Shovel Operation

Value Added

IMPROVED VIBRATION AND ENHANCED
DIGABILITY ALLOW PIT PROGRESSION TO
STAY ON TRACK
Blasts using the new timing recommended by Dyno 42
showed reduced vibration that allowed the mine to
disregard exceeding the scaled distance limitations. The
use of DigiShot electronic detonators serves to further
enhance the ability to create destructive interference
within the blast, further reducing vibration.
While the primary objective of this program was to control
and minimize vibration adjacent to critical, restricted
structures, empirical evidence has shown better cycle
times for the shovels leading to faster overburden removal
and increasing coal extraction. Eliminating decking
resulted in an increase in pattern footage by over twenty
percent (20%) effectively reducing drilling costs by unit
volume of material.

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 DYNO NOBEL ASIA PACIFIC PTY LIMITED or its affiliates as to the applicability of any procedures to any particular situation or circumstance or as to
 the completeness or accuracy of any information contained herein. User assumes sole responsibility for all results and consequences.
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