As underground mines increasingly focus on life-of-mine planning, understanding the long-term behaviour of structural devices plays an increasingly important role in ventilation and strata management planning.
Having led the field with full-scale live blasting testing of its shot blast products as early as 1998, the ability to engineer structures to conform to the most adverse site specifications has been a key feature of Aquacrete products.
Now, with structures in place in more than 80% of underground coal mines and an increasing number of hard rock mines throughout Australia, Aquacrete is well-placed to see how it’s products withstand the test of time.
With the high level of risk associated with the design and construction of dam walls and bulkheads, Aquacrete selected a New South Wales site where a combination of bulkheads and dam walls were constructed with Aquacrete Wet-Repel™ to verify it’s monitoring processes.
“Our observations and experiences in designing water-retaining structures with Wet-Repel™ confirm that the most significant factors influencing long-term bulkhead performance are the interface of the bulkhead with the surrounding strata as well as the potential magnitude of the hydraulic pressure to which they may be subjected,” according to Greg Kay.
Over a period of two years, regular site audits included a combination of visual inspections and non-destructive testing. Key areas of assessment included an inspection of surrounding strata to identify leakage, potential softening of the devices, erosion and breakdown of structural integrity and measurement of the devices’ thickness. In addition, the ‘health’ of the devices was verified using echo impact testing.
Following one event on site, where an unplanned power outage prevented water from being pumped outbye, the site engineer reported that the water head reached a height of 2.5m. The water pressure as a result of this incident was well in excess of the design specifications. While site engineers took all necessary precautions to maintain site safety during the event, inspection of the dam walls after the event confirmed that no water leakage occurred and the dam wall maintained full integrity.
“In many instances, the risk of a device failure has the potential to be catastrophic so as mines age and become increasingly developed, more attention needs to be placed on monitoring structural integrity of installed devices,” says Greg Kay, Aquacrete’s business development manager.
“Mine managers are looking for solutions that are not just cost-effective, but more importantly provide long term reassurance that the installations are still safe and strong. Having a reliable and accurate audit process – including our ability to non-destructively test devices in-situ provides substantial operational and safety benefits to the industry”, he explains.
“We are constantly developing new technologies and have ongoing interest in diversified uses for our products, but having tried and tested solutions is a great reassurance for mines,” he says.