Vibration Control Techniques Unlocks Additional Revenue
Document type: Case Study
Categories: Case Study

CASE STUDY

INNOVATIVE VIBRATION CONTROL TECHNIQUES
UNLOCK $1.82M IN ADDITIONAL REVENUE

$
 PROJECT GOALS
 MAINTAINING COMPLIANCE FOR FULL
 RECOVERY
 15,163 TONS OF TOTAL VALUE The objective of this project was to stay under a 1 IPS limit
 COAL RECOVERED OF $1.82M using any necessary means to allow for the full pit extent
 and recovery of saleable material. Increasing decking was
 no longer an option and the mine was constrained by drill
 size. Shots were already at the smallest size possible.
 BACKGROUND Thus, a new strategy was needed to promote compliance.

PIT EXTENTS NEARING CONTROLLED
STRUCTURE
DynoConsult was contacted by a surface coal mine
for assistance with vibration compliance. This mine is
a shovel and dozer operation located within the Illinois
Basin with two overburden seams of interest. The top
seam is blasted for half of the pit width and dug on the
other. The vibration-critical seam is this top seam, with Example of Customer Cast Blast
anywhere from 60 to 75 feet of overburden cast off every
shot. This area of vibration sensitivity is along a side
of the pit extents where multiple structures exist. As TECHNOLOGY APPLIED
of the time of writing, there were five structures being
monitored by five separate seismographs. Of these DYNO42 AND PRE-SPLIT DESIGN
structures, one required vibration control for compliance. Dyno42 is a proprietary software that utilizes signature hole
 input and analysis to determine the best optimized timing
The mine is under constant-monitoring compliance for schemes to minimize ground vibrations in both frequency
these structures. This state’s vibration limit is held at 1 and peak particle velocity (PPV). Signature hole analysis
Inch Per Second (IPS) when blasting to scaled distance is facilitated by detonating a singular hole within the same
compliance, regardless of frequency. The mine had working area as the blast.

nalysis
Inch Per Second (IPS) when blasting to scaled distance is facilitated by detonating a singular hole within the same
compliance, regardless of frequency. The mine had working area as the blast. This hole is loaded to the same
controlled this vibration with decking and number of specifications (burden, charge weight, stemming, etc.) as
holes within the shot but was at maximum number of the production blastholes. Dyno42 uses the waveform
decks allowed. Vibrations were nearing exceedances at from this singular hole to recreate the total blast vibration
over 100 feet farther away than expected, cutting the waveform that will occur from the production shot using
pit short of full extents. At the time of this project, the the principle of superposition. In this project, using
customer wanted to maintain sub-1 IPS compliance to Dyno42 allowed DynoConsult to analyze various Regular
allow for full recovery of material as stated by the mine Rhythmic Timing (RRT) delays to determine the lowest
plan. possible vibration outcomes. Regular Rhythmic Timing is
 the utilization of a common delay time (for example 25 ms)
 between all charges upon detonation, including between
 decks within the same hole.

Disclaimer: This case study is provided for informational purposes only. No representation or warranty is made or intended by Dyno Nobel 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, and, to the full extent permitted by law, Dyno Nobel expressly disclaims any liability arising from the use of this
document or the information contained herein. User assumes sole responsibility for all results and consequences. © 2020 Dyno Nobel

July 99%
 VALUE ADDED
DYNO42 AND SIGNASHOT PROMOTE Table 1. Reduction in vibration compared to modified
CONTINUED USE OF 2-DELAY BLAST scaled distance law prediction
PATTERNS
Since the customer had a site-specific scaled distance
 Due to the implemented strategy, the mine no longer had
law for this particular mine, the results will be presented
 to stop short of the mine plan due to blast vibrations. in comparison to the PPV prediction of said law. Before
 Now that complete coal extraction would go as planned,
the implementation of the above strategy, PPVs at the
 15,163 tons of coal could now be recovered again. At the
structure in question within this top seam were collected
 time of writing, a conservative estimate of $120.00 per ton
from a period of April 2022 to mid-June 2022. The global
 of coal will yield approximately $1.82 million for the mine. average indicated vibrations were 24% higher than what
the modified scale distance law predicted. It is important
 In addition to this recovery, compliance was the utmost
to note that the other monitored structures within this area
 goal for the customer to not only continue mining, but
were within the site-law predictions. to put all neighbors involved at ease. If complaints were
 being received, the customer would implement a self-
Once this strategy was implemented in mid-June of
 imposed change to remedy the situation.

CASE STUDY

Pre-Split is a common technique for creating a stable
 Time Period Vibration
highwall after a blast. Pre-splitting involves drilling out a
series of holes in a line along the back of the shot and
 April 128%
detonating these holes at a reduced charge weight. Less
commonly, it can be utilized to lower vibrations if set
between blast and structure. The customer had used pre- May 122%
split in the past as a means for highwall stability but not
as a means for reduction in vibrations at this mine. This 1st Half June 119%
technique was implemented along with RRT to provide
the highest likelihood of compliance. 2nd Half June 98%

put all neighbors involved at ease. If complaints were
 being received, the customer would implement a self-
Once this strategy was implemented in mid-June of
 imposed change to remedy the situation. DynoConsult
2022, results were collected for this same structure in
 aided in maintaining this relationship with the surrounding
question until the end of July. The results of the complete
 area. At the time of writing, the mine was on good terms
data collection can be seen in Table 1. The results are
 with the surrounding community. aggregated by month from April 2022 to the end of July. Red indicates before strategy implementation; green
indicates post-strategy implementation. The global
average of results after vibration control measures were
put in place was approximately 98% of the site-specific
modified scale distance law, a vibration reduction of
26% when controlling for distance and charge weight. There were no instances of vibrations being above the 1
IPS mark when this vibration control methodology was
implemented.