MASTER'S THESIS Mining the Närke Alum Shales Evaluation of Extraction Methods Suitable for the Närke Alum Shales Fredrik Johansson Master of Science (120 credits) Civil Engineering Luleå University of Technology Department of Civil, Environmental and Natural resources engineering Evaluation of extraction methods suitable for the Närke Alum shales Fredrik Johansson Department of Civil, Environmental and Natural resources engineering 1 Mining the Närke Alum shales Evaluation of extraction methods suitable for the Närke Alum shales This master thesis is made at the Department of Civil, Environmental and Natural resources engineering, Luleå University of technology By Fredrik Johansson Luleå 2012-11-30 Supervisors: Jenny Greberg, Luleå University of Technology Karl-Åke Johansson, Minexp AB 2 1 BACKGROUND .............................................................................................................................. 5 1.1 SCOPE OF WORK .......................................................................................................................... 5 1.2 METHOD ..................................................................................................................................... 5 2 ALUM AND OIL SHALES ............................................................................................................ 6 2.1 THE WORLD OIL AND URANIUM MARKET ................................................................................... 9 2.2 OIL SHALES IN THE WORLD ....................................................................................................... 10 2.2.1 Europe ............................................................................................................................... 11 2.2.2 Africa ................................................................................................................................. 12 2.2.3 The Americas ..................................................................................................................... 13 2.2.4 Asia .................................................................................................................................... 13 2.2.5 Middle east ........................................................................................................................ 15 2.2.6 Australia ............................................................................................................................ 15 2.2.7 Summary of the global oil shale status .............................................................................. 16 2.3 URANIUM IN THE WORLD .......................................................................................................... 16 2.3.1 Mining methods used for uranium mining ......................................................................... 18 2.3.2 Concentration and treatment methods used for uranium .................................................. 19 3 THE OIL SHALES IN SWEDEN ................................................................................................ 20 3.1 THE ALUM SHALES IN NÄRKE ................................................................................................... 20 3.1.1 Geology .............................................................................................................................. 21 3.2 THE ASKER AREA ...................................................................................................................... 23 3.2.1 Grades ............................................................................................................................... 24 3.2.2 Estimated amount of oil and Uranium .............................................................................. 25 3.2.3 Value of uranium in the Asker claim #1 ............................................................................ 26 3.2.4 Value of oil content in the Asker area ............................................................................... 26 3.2.5 Value of the deposit ........................................................................................................... 27 3.3 ROUGH ESTIMATION OF TOTAL URANIUM AND OIL CONTENT ................................................. 28 3.4 RARE EARTH ELEMENTS IN THE SHALES ................................................................................... 29 3.5 EXPLORERS FOR ALUM SHALES ................................................................................................ 30 4 EXTRACTION .............................................................................................................................. 31 4.1 AVAILABLE EXTRACTION METHODS ......................................................................................... 33 4.1.1 Description of geological properties of the Närke Shales ................................................. 33 4.1.2 Rock support and Q-value ................................................................................................. 35 4.1.3 Ex situ extraction ............................................................................................................... 36 4.1.4 Surface mining ................................................................................................................... 38 4.1.5 Underground mining ......................................................................................................... 40 4.1.6 In situ extraction ................................................................................................................ 48 4.1.7 Current in situ operations ................................................................................................. 51 4.2 EXTRACTION OF ALUM SHALES IN SWEDEN ............................................................................. 52 4.3 ENVIRONMENTAL CHALLENGES ............................................................................................... 53 4.3.1 Environmental impact of the different extraction methods ............................................... 54 4.3.2 Working environment ........................................................................................................ 54 4.4 PUBLIC OPINION AND MUNICIPAL VETO ................................................................................... 55 4.5 AVOIDING THE URANIUM. ......................................................................................................... 56 4.5.1 Recommendations .............................................................................................................. 57 5 REFERENCES .............................................................................................................................. 58 3 Summary The alum shales in the Närke deposit indicates an estimated in situ value of over 2 000 000 000 000 SEK The in situ value of the oil content alone is just under 900 SEK per ton (August 2011 prices, http://www.oil-price.net/, 2011). The high value of the deposit enables the use of more costly mining and extraction methods. Using a cut and fill method with road headers and ex situ extraction could be economically feasible, and this method could minimize the environmental impact to a level that would be acceptable. The uranium value is only around 10% of the total uranium + oil value. Every municipality has the right to veto against mining of uranium. Possibilities that can be explored are to only mine the oil from the shale, and regard the uranium as waste. This has never been tried before, and the strategy could be successful (Persson, 2012). Glossary alum shale type of shale in Sweden that can contain uranium and oil black shale type of shale that usually contain oil Cambrian time period 488 to 542 million years ago Drill core the core sample rod from a diamond drill hole exploration permit Permit for exclusive mineral rights extraction separation of material Fischer assay Method to measure oil extraction of shales in situ at the site, in place kerogen primitive state of oil leaching extraction of a material from a carrier particle into a liquid Närke Area in the middle of Sweden open pit a mine at the surface ore mineral that is economically extractable overburden side rock above the ore permeability property of how liquids or gases flows through the material porosity fraction between the volume of the material and the voids in bewteen the particles ppm parts per million REE Rare earth elements retort kiln that extracts oil Shale Sedimentary type of rock strip ratio ratio between ore and side rock underground mine a mine below the surface 4 1 Background The alum shales in Sweden have a high value (Svenska skifferoljeaktiebolaget, 2010). The shales contain oil, uranium and other valuable metals spreading over large areas. The company Svenska Skifferoljeaktiebolaget has an exploration permit with an area of about 70 square kilometers that could have an in situ value of several thousand million SEK. The company wants to know what extraction methods that are available today, and in the near future. They also want to know which of the methods that could be feasible to use when extracting the value materials from the alum shales in terms of economy and environmental impact. The deposits are large but have a low grade, some are located in domestic or farmland areas. One of the challenges is how to extract the valuable materials. The extraction has to be cost effective but at the same time the environmental impact has to be acceptable. Internationally, alum