Product Overview
Vari-Stem® is a patented stemming plug designed to maximize applied blast energy by improving confinement at the collar area of the blast hole. By reducing premature venting and stemming ejection, it enhances fragmentation and lowers overall blasting and processing costs.
Blast Energy Context
- Applied energy – shock & heave energy used in material breakage.
- Lost energy – Air over-pressure, ground vibration & excess fines caused by insufficient stemming.
- Vari-Stem® helps shift energy from “lost” to “applied” by improving energy confinement.
Significance of Scaled Depth of Burial (SDOB)
Scaled Depth of Burial (SDOB) is a critical engineering parameter used in blasting to measure the confinement of an explosive charge. It’s calculated as the ratio of stemming height to explosive column length, scaled to a reference of 10 hole diameters. This ratio helps engineers assess how well the explosive energy is contained within the blast hole—directly influencing safety, fragmentation, and overall blast performance.
When SDOB is properly controlled, it enhances rock breakage, reduces environmental impact, and improves compliance with safety protocols.
Key Features – Vari-Stem
- Sized for blast holes from Ø32mm to Ø251mm
- Tough moulded PVC construction
- Gear-profile design protects leads and allows water displacement
- Suitable for open-pit and certain underground applications
Performance Benefits
- Doubles stemming time to movement during blast
- Halves stemming ejection velocity
- Prevents explosive emulsion dilution
- Improves fragmentation in the cap rock zone
- Enhances dig, haul, and processing productivity
- Reduces fly rock and air blast
- Simple installation—minimal operator training required
Cost Efficiency
- Enables wider blast patterns with consistent fragmentation
- Reduces drilling and explosive costs
- Proven to lower total mining cost through energy optimization
Deployment & Compatibility
- Used globally in mining and quarrying operations
- Compatible with all explosive formulations
- Distribution by Oresome Products in Australia & Oceania since 2102
Ordering & Support
- On approved credit account or via secure credit card payment through eWay
- Bulk orders and technical support available
- Contact Oresome Products for sizing guidance and deployment tips
| Part# | Description | Bit size (mm) | QTY/box |
| 3-9396 | BP-2 Vari-Stem* | 51 | 210 |
| 3-9394 | BP-2.5 Vari-Stem* | 64 | 144 |
| 3-9393 | BP-3 Vari-Stem | 76 | 160 |
| 3-9395 | BP-3.5 Vari-Stem | 89 | 96 |
| 3-9392 | BP-4 Vari-Stem | 102 | 84 |
| 3-9402 | BP-4.5 Vari-Stem | 115 | 81 |
| 3-9426 | BP-5 Vari-Stem | 127 | 48 |
| 3-9427 | BP-5.5 Vari-Stem | 140 | 48 |
| 3-9428 | BP-6 Vari-Stem* | 152 | 30 |
| 3-9418 | BP-6.5 Vari-Stem | 165 | 21 |
| 3-9425 | BP-7 Vari-Stem | 177 | 18 |
| 3-C6112-8 | BP-8 Vari-Stem | 200 | 15 |
| 3-C6112-9 | BP-9 Vari-Stem* | 229 | 3 |
| 3-C6112-10 | BP-10 Vari-Stem plug* | 251 | 15 |
Further Reading
For a deeper understanding of stemming height optimization in blast design, we recommend the following peer-reviewed study: