MTi BLASTBAG™ Case Study – Boosting Productivity in Surface Blasting

Site Profile

• Material: Coal

• Bench height: 20 ft

• Stemming length: 12 ft

• Burden: 23 ft

• Spacing: 23 ft

• Hole diameter: 7 in (0.171 m)

• Explosive product: ANFO

The Challenge

At a surface coal mine in South Kalimantan, crews struggled with stubborn hard rock in the upper sections of blast holes. This caused poor fragmentation, longer digging times, and missed production targets.

The mine tried redesigning its blasts — moving from a 23x23x20 ft pattern with 100 lbs of explosives per hole, to a 23x23x23 ft pattern with 132 lbs. While fragmentation improved somewhat, oversize rock, flyrock, and higher vibration created new risks for nearby structures and communities. With site limits on charge per hole, they needed a solution that worked within vibration constraints while still improving productivity.

Having worked together before, the mine turned to MTi Group and its distributor PT. Prima Minechem Indonesia. The solution identified was air decking with BLASTBAG™ stemming plugs.

The Solution – Installing BLASTBAG™

Trials were set up to test whether air decking could improve stemming efficiency and fragmentation without increasing drilling or explosives costs.

Trial Methodology

• Review current blast design and practices

• Conduct proof-of-concept blasts

• Refine design for optimisation

• Measure and assess results

Blasts conducted:

• Blast 1 (POC): Split test (decked vs. non-decked), 23x23x20 ft pattern

• Blast 2 (POC): Split test, 20x23x20 ft pattern

• Blast 3 (Optimised): Full blast, 21x26x20 ft pattern

KPIs:

• Digging time ≤ 10 sec

• Powder factor < 0.15 kg/Bcm

• Max charge per hole: 100 lbs

• Top size < 20 in

Results

Blasts using BLASTBAG™ showed clear improvements:

• 8% reduction in P80 fragmentation

• 21% reduction in XMAX

• Digging times improved by up to 21%

The optimised blast design went further:

• Digging rates averaged 16% faster than the benchmark

• Drill and blast costs dropped by 8% (less powder, fewer drilled feet)

• Flyrock was significantly reduced thanks to better confinement

With all criteria met, the mine adopted BLASTBAG™ air decking across production blasts. Productivity returned, and costs fell without raising vibration levels.

This success highlights MTi Group’s leadership in blasting accessories like blasting plugs, gas bags, blast initiation machines, and explosive placards, supporting operations with proven solutions for better blasting.

About MTi Group

MTi Group is a global leader in blasting consumables including blast hole liners, blasting signs, handheld shooters, spider plugs, detonator caps, drill hole covers, and heavy-duty solar lights for mine safety.

Our solutions — from BLASTBAG™ gas bags to stem plugs, drill plugs, and surface drilling and blasting accessories — are engineered to deliver safer, more efficient, and more productive mining operations worldwide.

For more information on blasting machines for sale, 10 cap blasting machines, or our full range of blasting consumables, see our products below.