Green liquor dreg for injection into waste rock deposits (pilot scale)

Purpose and goal

Questions regarding up-scaling and how the technique works in different types of piles have been answered. It is now possible to answer questions about pump capacities, pipe installation and how the making of the slurry is best managed. It has been shown that injection can be economically competitive compared to other reclamation options. Amount green liquor dreg slurry injected was not enough (compared to the size of the mine waste pile) in order to see chemical effects. The project has started to enlighten environmental profits both for mining companies as for pulp and paper companies.

Expected results and effects

The test bed project has, in combination with some new projects that act to bring together pulp and paper companies to see their by-product as a product for the mining industry, opened up for a dialogue about green liquor dregs and injection. Interest about results have increased and it is nowadays easier to get to talk to authorities about the method. It is getting more and more commonly known that this method is about to be developed/that it exists. Swedish Environmental Protection Agency is also very proactive in supporting new solutions that uses non-virgin materials.

Planned approach and implementation

The project has put together experiments and trials performed during many years in smaller scale. This technique has mainly been developed for weathered waste rock and is prominent in this area because of (i) can affect the chemistry within a pile, (ii) can be used to complement an insufficient remediation, (iii) can be used at sites with low accessibility, and (iv) can be used where cultural and historical values are important to preserve. The project has created good opportunities for environmentally sustainable solutions both for the mining sector and for the pulp and paper industry.