What Is It?
The RAMJACK Backfill Monitoring System is comprised of two different types of Vibrating Wire (VW) pressure monitoring sensors, which are used in concert to measure the performance of backfill. The sensors are monitored in real-time from the first pour to the end of the mining process.
How Does It Work?
This system can deliver benefit wherever paste fill is used, however it is primarily used in Open Stoping underground operations. It is very cost efficient and lowers the environmental footprint by using the reject fines from the plant and allowing gravity to feed these back into stopes as paste fill. Best practice is to build a bulkhead on the lower level access to the open stope and pour high-quality cement to above the elevation of the back (ceiling) of the access drive to form a plug. With the plug in-place, less competent cement is used to fill the remainder of the stope.
The RAMJACK Backfill Monitoring System uses three total-pressure earth cells and one piezometer to manage and optimise the entire life cycle of the stope:
- Pressure against the bulkhead is measured during the pouring stage,
- The cement plug is detected at the end of the curing period of the first lift
- The effect of the rest of the pour is monitored after the load is removed from the bulkhead,
- The stress taken on by the backfill itself is measured after curing
Why Does It Matter?
The value of this RAMJACK system is that catastrophic bulkhead failures can be averted and the turnaround time of backfilling the stope can be significantly reduced. Moreover, the system helps mines reduce cement cost and maximise production when compared to environments not utilising a Backfill Monitoring System.