Cost-effective waste management of materials producing acid and metalliferous drainage (AMD) is essential for successful remediation. Considering this, using alkaline waste materials generated by other industrial processes represents a potential option for managing acid-forming mine wastes and is the focus of this sub-project being undertaken by PhD student Annah Moyo.

Mine waste materials were collected in early 2019 from six mine and smelter sites across Tasmania. Annah is currently assessing whether these acid-generating materials can be neutralised when combined with wastes from other industrial sites. An innovative series of bench-scale accelerated kinetic leach tests were initiated in 2019 and will continue for around 100 weeks to assess whether green liquor dregs, wood ash, coal ash, red muds, and scallop, mussel and oyster shells can ameliorate acid drainage generated by oxidation of the mine wastes.

Cost-effective waste management of materials producing acid and metalliferous drainage (AMD) is essential for successful remediation. Considering this, using alkaline waste materials generated by other industrial processes represents a potential option for managing acid forming mine wastes and is the focus of a new sub-project being undertaken by Annah Moyo. This PhD study commenced in December 2018, and is being funded by Mineral Resources Tasmania. Several industrial waste materials including red muds, green liquor dregs, boiler ash and spent shells are being sourced from across Tasmania and Victoria to test as AMD ameliorants. Mine waste materials are to be collected in early 2019 at several sites across Tasmania representative of high AMD and low AMD environments. Following the initial characterisation of waste materials in a series of static tests, they will be loaded into long-term (100 week) kinetic cells where different packing combinations will be evaluated. Once positive responses (i.e., neutralisation of AMD) have been identified they will be nominated for a field trial.

Cost-effective waste management of materials producing acid and metalliferous drainage (AMD) is essential for successful remediation. Considering this, using alkaline waste materials generated by other industrial processes represents a potential option for managing acidforming mine wastes. In this project, two boiler ash materials have been collected from an industrial source. Following their initial characterisation they are being added as a potential AMD ameliorant in static testing and kinetic testing experiments. The acid forming materials which were capped by these ash included pyritic tailings materials and sulfidic waste rock samples obtained from historic mine sites across Tasmania. This project discovered that the most efficient use of the boiler ash materials was to blend it with commercial lime (50:50) to cover low-sulfide, low As tailings where it would form a cement-like caliche layer effective at retarding oxygen ingress. These findings were reported at the 9th AMD Workshop, Burnie, Tasmania, in November 2017.

Cost-effective waste management of materials producing acid mine drainage (AMD) is essential for successful remediation. Considering this, using alkaline waste materials generated by other industrial processes represents a potential option for managing acid forming mine wastes, which this project aims to test.

In 2016, Honours student Rebecca Clifton assessed the use of boiler ash waste material from Norske Skog’s Boyer mill as an AMD ameliorant. Samples of waste rock and tailings from several sites around Tasmania, with very different mineralogical compositions, and therefore resulting water quality issues, were sourced for assessment of the effectiveness of utilising the paper mill waste in AMD control.

Results indicated that low-pyrite mine waste materials could be treated with boiler ash for limiting AMD, particularly if blended with commercial lime, as this encouraged the formation of a durable cement layer capping the tailings and retarding oxidation. Project results were presented to the Heavy Metals Project team at the Museum of Old and New Art (MONA) in December, with a journal article in preparation.