The geotechnical behaviour of tailings dams and thickened mine tailings or paste deposits can be defined by determining the compaction state and resistant properties.
One of the methods to achieve this is by using the PANDA®, a sophisticated Dynamic Cone Penetrometer (DCP) device. Now, the PANDA® technology is routinely being used to regulate compaction and provide in-depth quality control for tailings deposits, owing principally to its rapid, non-destructive, portable, easy-to-use and environmentally sustainable testing which is based on normalised methods and able to produce immediate results. The method also allows for the analysis of places which are difficult to access such as the slopes of sand tailings deposits.
Much of the ground work for this methodology was developed in Chile, along with the world’s first tailings specific technical standard.
Norma Chilena PANDA® NCh 3261-2012 – Depositos de Relave – Control de Compactacion con Penetrometro Dynamico Ligero (Tailings Deposits – Compaction Control with Dynamic Cone Penetrometer (PANDA®) – Chilean Standard NCh 3261-2012 (Spanish)
Mine tailings are frequently stored in dams. Often its the case that the coarse fraction (fine sands) of the tailings form the body of the dams, while the fine saturated fraction (sludge and silts) is poured by cycloning into the reservoirs of the dams thus formed. Due to the construction methods and materials used, these dams comprise failure mechanisms such as loss of stability, liquefaction, and internal and external erosion leading to major risks for the populations and their environments.
The mining industry is acutely aware of the need to continuously strive to minimise risks associated with all aspects of its operations. Failures of Tailings Storage Facilities (TSF’s) still occur with unacceptable regularity. There is at least one major failure per year somewhere in the world. The consequences of a TSF failure can be catastrophic, with multiple fatalities often occurring and significant environmental damage being almost assured. Therefore any procedures that can be implemented to reduce the likelihood of such events are likely to be embraced by the industry, as long as the outcomes are consistent, not prohibitively expensive and readily available.
The PANDA® penetrometer provides an approach that potentially satisfies these requirements. It has the major advantage of portability, as it can be carried, set up, and operated by a single operator, relatively little training is required, and the test itself is quick. It means that multiple profiles can be tested in a single day, tests can be carried out on embankment slopes (unlike most machine-mounted penetrometers) and the equipment is relatively inexpensive.
To review some of the research, see Mining Tailings Applications.