The promise of thickened, paste, and filtered tailings is reduced makeup water demand, smaller impoundment footprints, and less environmental impact. The promise is the opportunity to practice responsible, sustainable mining.
The forty-two papers accepted for Paste 2013 to be held in Belo Horizonte in June 2013 will facilitate progress towards the promise of better, more cost-effective tailings management.
Papers comparing thickened, paste, and filtered tailings to conventional wet disposal practice, show why trying to reduce the moisture content of the tailings and increasing tailings solids content is a worthwhile effort. Other papers consider the benefits and challenges faced in Brazil, Chile, and Canada in permitting, constructing, and operating tailings facilities with dewatered tailings. It is not always easy to do, and these papers tell us why and provide pointers to how we can succeed.
To produce thickened, paste, or filtered tailings, expensive equipment is needed. In Paste 2013, we have five papers on improved, new, and innovative equipment and technical approaches from those in the industry who are making and selling the required equipment. A paper from Outotec talks of balancing the cost of the energy needed to dewater the tailings against the cost savings involved in managing the tailings. A paper from FLSmidth reports on pressure filtration of alumina refinery bauxite tailings. A paper from BASF tells of novel flocculants technology. Paterson & Cooke write of pipe loop tests to measure the rheology of tailings at the Codelco mine. C. Karambalis tells of a pulsation free hydraulically driven piston pump. In years to come these applications may become standard; but for now they are new and the seminar is the place to interact with those making the advances.
The mining industry has contributed many fine papers on practices implemented at mines worldwide. We have papers from staff of ExxonMobil, Imperial Oil, and ArcelorMittal. A. White of Xstrata Copper in Canada writes of practices at the Kidd Mine to reduce pipe wear by dewatered tailings. Short of a world tour of mines, the best way to learn about actual mine practice is to converse with those who are succeeding at mines worldwide.
Cyclones are discussed in two papers. Fraser Alexander staff write of the use of cyclones to dewater tailings. J. Landriault and P. Primeau write of the application of cyclone technology in paste backfill plant design. There is life yet in cyclone technology.
The promise of steeper beaches and hence smaller perimeter embankments is at the heart of selection of thickened and paste tailings operations. We have at least five papers on the contentious issue of beach slope and inclination. These papers report a move away from the four to five per cent inclinations previously promised and tell us why, on the basis of recent comprehensive testing, we can expect beach inclinations of one per cent and maybe even less. This finding is sure to be much debated during the seminar. A paper on a large tilt flume to test for beach slope will surely be at the centre of these debates.
Not to be debated is the fact that placing tailings as backfill underground is a good thing to do. However, it is not always easy to do. N. Gridley and L. Salcedo of Anglo American write of the use of cement paste to backfill underground mines in Chile.
There are some papers that truly advance the state of knowledge. D. Rojas, L. Fernandez and R. Janssen of Bechtel write of the design of open channels for non-Newtonian fluids. P. Simms and his colleagues at Carleton University write insightfully about desiccation, dewatering, and gain of strength in deposited tailings. P. Slatter of ATC Williams writes of the behaviour of paste when flowing as a sheet of material. M. Musse and J. Lupo write of the problem of dealing with increased erosion of dewatered tailings as disposal volumes increase and global warming produces greater precipitation. Merely hearing these new and insightful perspectives would justify seminar attendance.
There are several papers about the fascinating challenges Brazilians face in dewatering tailings. M. Silva Marques and F. Perez write of the status of thickened, paste, and filtered tailings in Brazil. Each of the other papers on Brazilian problems, practice, and solutions is a valuable addition to the literature and the industry.
Alberta oil sands tailings are the subject of five papers – it is a compliment to the Paste Conference series that the people of the Alberta oil sands industry continue to support this seminar series. The oil sands are experimenting and field testing new ways of dewatering and depositing tailings. They are looking hard at cyclones, thickeners, centrifuges, polymer injection, and the application of consolidation and freeze-thawing to improve the long-term properties of tailings facilities. Their experience and expertise will be a valuable learning experience for all seminar attendees, who may pick up ideas and opportunities to take back to their mines.
The point is that the papers accepted for Paste 2013, as always in this seminar series, advance knowledge, practice, and the state-of-the-art of stacked tailings, whether it be thickened, paste, or filtered. It is good to read the papers; but there is no substitute for hearing the authors present their work and participating in the discussions that follow. Come and join us in Belo Horizonte.