Increasing Tunnel Advance Rates at Procon Forrest Kerr
Document type: Case Study
Categories: Case Study

CASE STUDY

INCREASING TUNNEL ADVANCE RATES AT PROCON
FORREST KERR

PROJECT SUMMARY
IMPROVED UNDERGROUND DEVELOPMENT
PRODUCTIVITY WITH OVERALL LOWER COST
Procon Group was challenged to meet their tight tunnel
advance schedule, mining a large heading, 9.6m wide
by 9.8m high, with 5m deep rounds using conventional
NONEL® LP initiation system, Spartan 90g primers and
Titan 7000 RU. With 144 holes in each round and only
19 delay periods, many holes had to be initiated on
the same delay time. Various burn cuts using LPs and
various breaker holes were tried in order to improve the
inconsistent pull rates and resulting perimeter over break.

roject timelines. rock works for AltaGas’s Forrest Kerr project, a 195 MW
run-of-river hydroelectric project. The project is located in
British Columbia, approximately 1,000 km northwest of
Vancouver. TECHNOLOGY APPLIED
The project will capture a portion of the Iskut River energy
produced by the natural water flow and elevation drop to USING THE DIGISHOT ELECTRONIC INITIATION
produce and deliver clean, renewable electrical power to SYSTEM
the grid at Bob Quinn Lake via British Columbia Hydro’s Improved productivity is realized using high precision
287-kV Northwest Transmission Line. DigiShot electronic timing from DigiShot electronic initiation system.The
initiation system are being used for 5m deep rounds for accuracy of the DigiShot detonator is 0.02% over the
approximately 2,000m of the 9.6m wide x 9.8m water entire timing range (0 – 20,000ms) compared to NONEL,
diversion tunnel. which is in the order of 2% variance of the period delay
 time.

One solution was to evaluate the DigiShot® electronic Initially a smaller 5 x 6m relief tunnel was conventionally
initiation system in order to provide greater detonator blasted in the top middle section of the larger tunnel
accuracy and delay timing flexibility to help increase excavation. advance rates. While the detonator cost per unit is greater,
the overall per meter of advance cost was reduced with
less over break, increased advance rates, and fewer PROJECT GOALS
booted holes to drill around. INCREASE TUNNEL ADVANCE RATE
 The principal goal was to demonstrate DigiShot initiation
 could be construction miner friendly and efficient to
 BACKGROUND improve the overall advance rate of the underground
 tunnel. Faster advance rates would also result in overall
HYDROELECTRIC TUNNEL PROJECT lower operating costs and help the project better meet
Procon is responsible for executing all the underground project timelines. rock works for AltaGas’s Forrest Kerr project, a 195 MW
run-of-river hydroelectric project. The project is located in
British Columbia, approximately 1,000 km northwest of
Vancouver.

CASE STUDY

Key features of the DigiShot initiation system:
 • The ability to check the status of all detonators before
 programming, arming and firing allows the blaster to
 address any problems prior to the blast event
 • To pre-program the timing of the development rounds
 based on engineer recommendations and experience
 • The ability to make adjustments at the face based on
 lost holes and misplaced drill holes

These features provided Procon with no priming failure
errors and no surface hook up errors compared to
conventional initiation systems. The development rounds
were able to be primed, loaded, hooked up, and tested for
leakage and failures within the same amount of time.

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

DigiShot initiation system helps yield consistent results
 by:
 VALUE ADDED • Improved loading accuracy, timing pattern provides
 double check to insure all drilled holes are loaded,
MINER FRIENDLY WITH GREATER BLASTING (using conventional LPs, 1 to 2 holes on average were
CONTROL AND EFFICIENCY being missed). Using the DigiShot electronic initiation system, the • Eliminating miners variability in timing of rounds (same
underground tunnel advance rate was increased with the times are used for all rounds, they are pre programmed
elimination of 1m booted holes. The rounds consistently into blast box). pulled >95% with half barrels visible on nearly most • Insuring all loaded detonators are connected using the
perimeter holes. Compared to traditional NONEL LP electronic initiation equipment for testing and verifying
timing, the DigiShot system was able to deliver a number of detonators (on random audits using conventional
of important benefits including: LPs, 1 hole on average was not hooked up and 2
 • Reduced scaling time (average scaling time went from to 3 holes were hooked up in an unreliable initiation
 three hours to less than one hour). position). • Increased fragmentation, resulting in faster mucking The DigiShot electronic initiation system proved to be
 times and higher bucket fill rates.

ation
 three hours to less than one hour). position). • Increased fragmentation, resulting in faster mucking The DigiShot electronic initiation system proved to be
 times and higher bucket fill rates. miner friendly for this large civil construction project
 • Reduced overbreak, half boreholes were consistently and dramatically increased the overall efficiency of the
 visible on nearly all perimeter holes within the round, tunnel advance rate while improving safety with improved
 the only time the perimeter half boreholes were not perimeter control and reduced booted holes. visible was due to overbreak to a geological fault
 running within 1m of perimeter wall. • Simplified inventory (only 1 detonator product instead
 of 19 delay periods). • Improved fragmentation provides an opportunity
 to reduce the amount of holes drilled and loaded,
 increasing overall productivity while reducing drilling
 and loading costs, without increase time.