Conference Agenda

Thursday, 15/July/2021:
12:40pm - 2:20pm

Session Chair: Gareth Farr
Location: Meeting Room 3

12:40pm - 1:05pm

🎓 Carbonation Of Magnesium Silicate Minerals In Mine Waste: Practical Laboratory Testing Methods To Assess The Dual Opportunity For Carbon Capture And AMD Mitigation

Rhys John Savage1,2, Malvina Chmielarski1,2, Andrew Barnes1, Steven Pearce3, Mark Roberts1, Phil Renforth4, Seth Mueller5, Devin Sapsford2

1Geochemic Ltd, United Kingdom; 2Cardiff University, United kingdom; 3Mine Environmental Management Ltd, United Kingdom; 4Heriot-Watt University, United Kingdom; 5Boliden AB, Sweden

Mineral carbonation has been widely recognised as an important mechanism in the sequestering of CO2into mining wastes and by-products. The generation of fast-reacting carbonates in the carbonation process may also have important implications for the mitigation and prevention of acid mine drainage (AMD). Laboratory-scale methods have been developed to assess carbonation potential in mine by-products from an active nickel mine site in Finland. Utilized methods allow assessment of key parameters controlling the carbonation process. It has been demonstrated that the methods can influence waste pore water chemistry and geochemistry as a result of the carbonation process.

1:05pm - 1:30pm

Beneficiation of Salts Crystallized from Lake Katwe Brine

Joseph Ddumba Lwanyaga1,2, Hillary Kasedde2, John Baptist Kirabira2, Alan Shemi3, Sehliselo Ndlovu3

1Busitema University, Uganda; 2Makerere University, Uganda; 3University of Witwatersrand, South Africa

A salt extraction process to enhance the quality and quantity of salt produced at Lake Katwe in Uganda is presented. To validate the designed process, laboratory experiments were conducted. The techno-economic analysis of the process flow sheet was modeled and simulated by SuperPro Designer. Halite of purity >98% was obtained by floating burkeite and trona which co-precipitate with it during evaporation. The other feasible products of the process are soda ash and sodium sulfate. With a net present value of US$25,077,817, the proposed process is economically viable.

1:30pm - 1:55pm

Potash Dump Leachates – Challenges from Environmental Regulatory Requirements and Climate Change

Anne Weber1, Antje Ulbricht2, Alexander Müller3, Astrid Gessert3, Felix Bilek2, Thomas Sommer1

1Dresden Groundwater Research Centre e.V; 2GFI Groundwater Consulting Institute GmbH Dresden; 3Lausitzer und Mitteldeutsche Bergbauverwaltungsgesellschaft mbH, Division Pottash-Spar-Ore

In a German former potash mining district, highly saline leachates (120 g/L chloride) from three potash dumps are collected in a basin and discharged into the receiving river in a controlled manner. This work illustrates the increasing constraints but also obstacles towards management of saline dump leachate that does not rely on dilution. Besides dump covering, evaporation of leachate is considered the most promising approach to reduce salt load into surface water in the long term and is currently put forward. Here, linking energy and material fluxes on a local basis is pivotal during development of a feasible process.

1:55pm - 2:20pm

Recovery Of Cobalt And Copper From Tailings Through Enhanced Oxidation And Selective Precipitation

Mark Roberts, Nina Swain, Andrew Barnes

Geochemic Ltd, United Kingdom

The oxidation of high sulfide tailings by ozone coupled with selective precipitation was investigated as a technique for the recovery of cobalt and copper. Iron was selectively removed from solution as precipitated oxides, with only minor loss of cobalt and copper. The remnant cobalt and copper were then precipitated out of solution forming a concentrate with 8.15% Co and 8.73 % Cu with recovery rates of approximately 0.175 kg/tonne achieved. This technique, though in its early stages of development, demonstrates considerable promise as a waste valorisation system which is also capable of reducing latent acidity potential in the waste stream.