MTi BLASTBAG™ Case Study – Flyrock Reduction in Surface Blasting

The Challenge

Picture a gold mine in West Africa pulling more than 85,000 ounces a year. Big operation. Good people. And a problem they couldn't shake.

Every blast near the boundary was a gamble. Ejections kept happening. Flyrock kept flying. And the boundary wasn't open desert — homes and public infrastructure sat right there.

*Image of flyrock at the West African Gold Mine

The crew tried everything they knew. New blast designs. Blast mats. Tweaks on top of tweaks. Nothing worked.

Then a tragic incident forced their hand. Drilling and blasting near the boundary stopped completely. Production took the hit, but they weren't going to risk another life until they found a safer way to blast.

That's when they called MTi Group.

The Solution – BLASTBAG™ Air Decking

Here's the thing about flyrock. It usually traces back to the same handful of issues — poor stemming, confinement problems, or overcharging. Fix the stemming, and you fix most of the story.

So MTi proposed air decking with BLASTBAG™ gas bags. The idea is simple: create an air deck inside the blast hole, take the upward pressure off the stemming, and let the energy distribute the way it's supposed to.

Better confinement. Same fragmentation. Fewer ejections. That's the goal.

But MTi didn't just ship product and walk away. Their blasting experts worked side by side with the crew on engineering support and blast design changes, so the trials could run safely from day one.

Trial Methodology

The plan was straightforward:

1. Review the current blast design and stemming practices
2. Design test blasts
3. Measure and assess the results

Blasts conducted:

• Blast 1 (POC): 10x10x39 ft, split test (decked vs. non-decked)
• Blast 2 & 3 (Optimized): 10x10x39 ft, 8.2 ft stemming + 4.9 ft air deck, 5 in hole diameter

Charge weight:

• Standard: 315 lbs per hole
• Optimised: 282 lbs per hole

Results

The first blast told the story right away. The BLASTBAG™ decked holes held tight — better confinement, far less ejection. The non-decked holes behaved like they always had.

Blast 2 went even further. Excellent confinement, a major drop in flyrock, and strong fragmentation across the pattern.

Blast 3 confirmed it wasn't a fluke. Same safe performance. Same consistent improvements.

By the end of the trials, the picture was clear:

• Flyrock incidents dropped to near zero
• Charge per hole reduced by 33 lbs (315 → 282 lbs)
• Safer blasting resumed along the boundary

Less explosive. Less upward pressure on the stemming. Better Confinement. Less risk. Better blast.

Adoption

The operator rolled BLASTBAGS™ into production blasts across the site. With on-site support from MTi Group and our distributor EDM African Resources, the mine got back to work — and the surrounding community got their confidence back too.

About MTi Group

MTi Group is a global leader in blasting consumables and blasting accessories for mining and quarrying.