August 29, 2017
- Testing of hydrocyclones for separation of sand and clay fraction produces sharper cut increasing halloysite / kaolin yield from 22% to 30%
- Sharper cut produces cleaner sand fraction, better flotation results expected with less fine clay in the sand fraction
- Flash calcination work produces whiter metakaolin product, testing underway at CTL Thomson
- initial separation using hydrocyclones together with flash calcination would reduce plant size and in turn is expected to reduce CAPEX
Vancouver, B.C. August 29, 2017 - I-Minerals lnc. (TSX.V:IMA; OTCQB:IMAHF; Frankfurt 61M) (the “Company”) is pleased to provide an update on test work at FLSmidth Krebs in Tucson, AZ that successfully demonstrated the use of hydrocyclones to make the initial clay (kaolin-halloysite)/sand (quartz-k-spar) separation. The testing was a recommendation of Millcreek Engineering of Salt Lake City Utah.
“This latest testing of alternative processing technologies has generated some highly encouraging results,” stated Thomas Conway, President and CEO of I-Minerals. “The use of hydrocyclone technology stands to increase the amount of halloysite and metakaolin available for sale, which of course would increase clay revenue, while the use of hydrocyclones together with the use of a flash calcination system stands to reduce the required floor space as compared with the feasibility design offering some modest CAPEX savings. There may even be a small OPEX saving from the processing of a cleaner sand fraction. We are very pleased with the results and look forward to the CTL Thomson test results of the metakaolin product produced during this test work.”
The current process plant design used screw classifiers and previous pilot plant work used a blunger mixing/settling/decanting methodology. Hydrocyclones improved the separation of the primary clay and sand fractions producing a sharper cut that increased the clay fraction yield to about 30% compared to approximately 22% in the previous pilot plant work.
This cleaner cut impacts both the sand and clay fraction as any clay material not recovered in the clay circuit remains with the sand fraction and is ultimately lost to tailings during desliming efforts prior to flotation of the sand fraction to make the k-spar and quartz products. Hence the cleaner sand fraction should be easier to float with reduced reagents needed and less attribution scrubbing to deslime the sand fraction. The hydroclyone circuit will replace a conventional double-pass screw classifier system and will ultimately decrease the footprint of the equipment requirements in this portion of the circuit.
In a separate evaluation, kaolin clay from the hydrocyclone separation was provided to FLSmidth in Allentown, PA for test production of a metakaolin product using flash calcination. Traditional calciner production uses horizontal kiln technology requiring significant retention time at temperatures typically ranging from 850-900°C to achieve the necessary pozzolanic results. The flash calciner is vertically oriented and uses gas to propel the material through the unit with very limited retention time requirements.
It is expected the same quality of metakaolin can be achieved at lower overall temperatures. For this evaluation testing was conducted at 50°C intervals from 650-850°C. Only the initial 650°C temperature failed to meet the desired metakaolin Loss on Ignition (LOI) target specification. No operational issues were observed during the testing and it is FLSmidth’s recommendation that flash calcination be considered as a replacement for I-Minerals’ conventional metakaolin processing circuit. A flash calcination system would further reduce the plant footprint and generate modest additional CAPEX savings. In addition, as compared with previously produced metakaolin products, the metakaolin produced through the flash calcination appears comparatively whiter to the naked eye. A formal whiteness assessment will be part of the work at CTL Thomson.
Samples of the metakaolin test products that met the LOI threshold have been sent to CTL Thomson in Denver, CO for physical testing. A key benchmark test being evaluated is the water requirement test. Empirical studies indicate that the particle size and shape from flash calcination systems yields a product with a lower water demand – an important consideration to cement companies when evaluating a Supplementary Cementitious Material (a SCM or pozzolan). Prior work at CTL has shown metakaolin produced from IMA’s Bovill Kaolin project produces a highly reactive metakaolin rendering excellent strength numbers.
A. Lamar Long, CPG, is a qualified person (“QP”) for I-Minerals Inc. and has reviewed and approved the contents of this release
About I-Minerals Inc.
I-Minerals is developing multiple deposits of high purity, high value halloysite, quartz, potassium feldspar and kaolin at its strategically located Helmer-Bovill property in north central Idaho. A 2016 Feasibility Study on the Bovill Kaolin Deposit led by GBM Engineers LLC, who were responsible for overall project management and the process plant and infrastructure design, including OPEX and CAPEX calculated an After Tax NPV of US$249.8 million with a 25.8% After Tax IRR. Initial CAPEX was estimated at $108.3 million with a 3.7 year After Tax payback. Other engineering services were provided by HDR Engineering, Inc. (all environmental components; hydrology / hydrogeology; road design); Tetra Tech, Inc. (tailings storage facility design); Mine Development Associates (mine modelling; ore scheduling; mineral reserve estimation); and SRK Consulting (U.S.) Inc. (mineral resource estimation). The project has received mine and water permits from the State of Idaho.
Per: “Thomas M. Conway”
Thomas M. Conway, President & CEO
This News Release includes certain “forward looking statements” within the meaning of the United States Private Securities Litigation Reform Act of 1995. Without limitation, statements regarding potential mineralization and resources, exploration results, and future plans and objectives of the Company are forward looking statements that involve various risks. Actual results could differ materially from those projected as a result of the following factors, among others: changes in the world wide price of mineral market conditions, risks inherent in mineral exploration, risk associated with development, construction and mining operations, the uncertainty of future profitability and uncertainty of access to additional capital.
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