Collection: Underground

Underground drill and blast is the work that turns ore body into mineable rock — drifts, drives, ramps, stopes, and the development blasts that open the next bench. The conditions are different from surface mining in every way that matters. Holes are smaller. The face is closer. Groundwater shows up where you least want it. Reactive ground hits without warning. Service air is on tap from mine infrastructure, but only if your kit knows how to use it. And the upholes — the holes that fight gravity during charging — are where most underground blast problems start.

MTi GROUP's underground range is built for these conditions specifically. Nine products are UG-only — SLUMPSTOPPA, MITIPLUG, MultiFit Spider, BAG SPIDER, and the BLASTBAG ACE II UG. Another 266 cross-functional products cover the rest of the underground blast — loading, measuring, safety, inflation, signage, locks. Used at underground mines across gold, copper, nickel, coal, and hard-rock metals globally.

What Makes Underground Blasting Different

• Smaller hole diameters — production holes typically 2"–4.5" (50–115 mm); long-hole stope work goes up to 6"–10" (152–254 mm)
• Upholes change everything — emulsion wants to slump back down, ANFO wants to fall out, and gravity works against the loaded column until the cap fires
• Service air infrastructure — mine air is already on the level, so air-operated BLASTBAGs (AERO, BLASTBALL) install faster than aerosol or chemical alternatives
• Groundwater — wet ground in upholes wrecks emulsion and demands lined holes or wet-rated plugs
• Reactive ground — sulfide ore bodies and other heated formations need temperature monitoring before any charge goes in
• Confined space — load poles, hose reels, and inflation kits have to work in a 3 m × 3 m heading, not a 50 m bench

What MTi Supplies for Underground

Every UG blast needs three things: getting the charge to the bottom of the hole, holding it there, and inflating or installing the plug above it. Every category in the catalog has UG-specific products.

• BLASTBAGS™ — BLASTBAG AERO (compressed air via mine service line) is the underground best-seller; BLASTBAG ACE II UG (chemical reaction, no aerosol, no metal) for sites with strict DG storage rules.
• BLASTBALL™ — air-inflated wet-hole plug with hermetic bladder and tire-strength nylon webbing. The only inflatable rated for deployment through water.
• Stemming Plugs — MITIPLUG holds emulsion or ANFO in upholes with a flexible pilgrim-hat fin; the fins let the column gas through. SLUMPSTOPPA does the same with polymer bristles for emulsion specifically.
• In-Hole Accessories — MultiFit Spider centers the booster in the column; BAG SPIDER clamps onto BLASTBAG ACE UG so the bag can be deployed quickly and left in place during inflation.
• Inflation Equipment — Underground Hose Reel, dropline hoses, AB-C couplings, and handheld inflators that deliver mine air to the bag at depth.
• Loading — wooden load poles in 5–12 ft (1.5–3.7 m) lengths with non-sparking copper alloy ends. Tamping plugs and barbed retrievers for charge placement and recovery.
• Measuring — Tape & Reel, Depth Gauge, MITIMEASURE Polyline (premium stainless-steel for QAQC in wet conditions), plus the Blast Hole Temperature Probe for reactive ground.

The Underground Blast Problems This Kit Solves

• Emulsion slumping in upholes — SLUMPSTOPPA, MITIPLUG, BLASTBAG AERO, BLASTSHIELD liner (for severe groundwater cases)
• Booster drift — MultiFit Spider centers the primer in the explosive column
• Wet holes and breakthroughs — BLASTBALL air-inflates against the hole wall; BLASTSHIELD lines the column
• Reactive ground — Blast Hole Temperature Probe confirms safe loading temperatures before charging
• Tunneling and narrow headings — SPRINGLOCK mechanical plug for 1.75"–2" cartridge work
• Cap-hole priming — Brass Powder Punch, OSHA 1910.109 compliant

Why MTi Group for Underground

The underground kit is designed by people who've been on a level, not engineers who've only seen surface benches. Non-sparking metals where it counts. Sized for the smaller diameters and tighter spaces UG operations actually run. AS 2187.2:2008 explosives compliance baked into product design. Same-day shipping from Stanton, KY so production isn't waiting weeks for a coupling, a plug, or a load pole end. And the technical team takes the call — no chatbot, no overseas escalation when you've got a stope to load.