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Slope stability
Published in W. A. Peck, J.L. Neilson, R.J. Olds, K.D. Seddon, Engineering Geology of Melbourne, 2018
Landslippages have occurred where the Tertiary Balcombe Clay outcrops in the cliffs and wave cut platforms adjacent to Port Phillip Bay south of Frankston. Such situations include Olivers Hill and other locations further to the south including Davey’s Bay, Manyung Rocks, and Fossil Beach (Gostin 1966). At Olivers Hill the landslippage is related to an ancient slump earth flow complex which appears to have originated by shear failure on the gently seaward dipping highly plastic Balcombe Clay (Neilson, 1985). The slide areas below Olivers Hill were active in the 1960’s and early 1970’s, and a number of houses were destroyed. Comparison of existing fences with old survey data indicates a total displacement of some 3 metres over a period of 100 years. It appears that improvements in drainage which resulted from the introduction of sewerage to the area and improved storm water drainage of the area in the mid 1970’s has slowed but not necessarily arrested all movement. In the slips where the Balcombe Clay outcrops at sea level continued wave erosion is resulting in progessive unloading of the toe to the slips and further movements are likely.
United Kingdom and Ireland
Published in Ian Sims, Alan Poole, Alkali-Aggregate Reaction in Concrete: A World Review, 2017
The coarse aggregate comprised mainly crushed diorite or granodiorite from a large quarry at Ronez on the north coast of Jersey, mixed with a smaller proportion of beach gravel containing rounded pebbles of ‘Jersey shale’, chert and various igneous rocks including dacite. The fine aggregate was a fossil beach sand from a pit at St Ouen’s Bay, comprising quartz, quartzite and feldspar, with small amounts of chert, shell and various igneous materials. Although the beach aggregates were found to contain some potentially reactive constituents, principally chert and dacite (acid volcanic rock), there is little evidence that these materials reacted within the dam concrete. The reactive silica was present as secondary hydrothermal veining and vugh fillings within the crushed dioritic rock aggregate source. The veining material, which is associated with shear zones and lamprophyre dyke zones within the quarry, comprised variable mixtures of chalcedony and opal. These vein and chalcedonised lamprophyre materials showed reaction within a few days at 20 °C in the gel pat test (see Figures 6.5 and 6.6), whereas no such rapid reaction could be obtained with the chert and dacite particles from the beach deposits (Sims, 1977).
The long uphill journey of Australia’s rare earth element industry: challenges and opportunities
Published in International Journal of Mining, Reclamation and Environment, 2022
George Barakos, Laurence Dyer, Michael Hitch
Another significant potential producer of rare earth oxides is Iluka, through their heavy mineral sands mine in Eneabba, 300 km north of Perth, on the country’s west coast. The deposit was discovered in 1970. Several companies opened mines, and there was a gradual consolidation process. Iluka Resources Ltd. was formed in 1998 and has been mining mineral sands at Eneabba to the present day. The recovery project involves extracting, processing, and selling a monazite-rich tailings stockpile stored in a mining void at the site. Iluka commissioned a concentrator plant at Eneabba to further process the stockpiled material. The goal is to separate the monazite (and additional zircon), producing a monazite concentrate material that will directly feed Iluka’s future rare earths refinery. In April 2022, the company board approved the investment of USD 850 million for building a fully integrated REE refinery on site [4]. The refinery is planned to have a production capacity of 17,500 tonnes per annum, with the first production earmarked for 2025, and the products being neodymium, praseodymium, dysprosium, and terbium oxides. The refinery will be fed initially from the Eneabba stockpile. Potential future feedstock sources include Iluka’s Wimmera and other deposits and a range of third parties. Like the fossil beach sand deposits at Eneabba are the heavy mineral sands at Capel, Yoganup and other strandlines in the southwest of Western Australia. Besides rutile and zircon, REE and thorium contents are included in Capel and Yoganup, being exploited since the 1990s [28]. Over 1.9 Mt of heavy mineral concentrates were produced in Yoganup from 2004 to 2009 [29].