Aton Announces The Final Results Of Column Leach Testing Of Hamama West “Gold Oxide Cap” Samples, With Average Oxide And Transition Zone Gold Recoveries Of 75.6% And 72.7% Respectively
Vancouver, February 22, 2018: Aton Resources Inc. (AAN: TSX-V) (“Aton” or the “Company”) is pleased to provide investors with an update on the results of the column leach metallurgical testwork completed on bulk composite samples from the “gold oxide cap” portion of the Hamama West deposit, located in the Company’s 100% owned Abu Marawat Concession, located in the Eastern Desert of Egypt.
4 bulk composite samples of Hamama West “gold oxide cap” mineralisation consisting of 2 oxide zone and 2 transition zone samples underwent column leach testing for a period of 70 days;
The 2 oxide zone samples were crushed to an optimum size of -12.5mm, with one sample agglomerated with cement (sample OBC-1), and the other not being agglomerated (sample OBC-2). The 2 transition zone samples (samples TBC-3 and TBC-4) were combined and homogenized, with one sample tested at a crush size of 100% passing -12.5mm, and the other sample tested at a crush size of 100% passing -8mm;
The 2 oxide zone samples returned gold recoveries of 77.9% and 73.3% (average 75.6%), and silver recoveries of 42.6% and 43.1%, from the column leach tests;
The 2 transition zone samples returned gold recoveries of 73.2% and 72.1% (average 72.7%), and silver recoveries of 32.9% and 39.6%, from the column leach tests;
The column leach tests indicate fast initial leach kinetics for gold and silver, with a long leaching period tail.
Commenting on the column leach test results, Mark Campbell, President and CEO of Aton stated, “These metallurgical test results confirm our belief that heap leach processing at Hamama West is the most attractive option for processing the “gold oxide cap” at Hamama West. This latest round of metallurgical testwork strongly confirms the results of the previous coarse bottle roll leach testing. The volume of testwork now completed has consistently produced high gold recoveries from the “gold oxide cap”, demonstrating its amenability to processing with heap leach technology. The results of this testwork will be used to form the basis of the heap leach process design and be used in open pit optimization runs”.
Metallurgical testwork programme
Four (4) bulk composite samples were dispatched to Wardell Armstrong International (UK) in Q4 2017 for metallurgical testing at their Truro laboratory. Two (2) representative 120kg bulk composites, consisting of HQ or PQ sized half core drill samples, from each of the oxide and transitional zones of the Hamama West deposit, and representing material from the upper “gold oxide cap” portion of the deposit, were selected and dispatched for testing. Initial testwork included head assays, coarse and fine bottle roll leach tests, and percolation and agglomeration tests. Variable parameters of crush size and cyanide concentration were tested. Optimal test conditions derived from the coarse bottle roll leach and percolation/agglomeration tests were used to set the parameters for the column leach tests, which were started on November 27, 2017 to determine the final gold and silver leach recoveries obtainable using heap leach technology. The column leach tests were terminated after 70 days.
The results of the column leach tests are summarized below in Table 1, and the leach curves for the 4 samples are shown in Figure 1.
Table 1 – Results of column leach testing
Based on these column leach test results received to date, the following observations can be made:
The oxide column OBC-1 was carried out using cement to assist with the formation of agglomerates. Agglomeration is required to ensure that high percolation rates are achieved in the heap leach pad. The transitional ore did not require an agglomeration stage. There appears to be no benefit with respect to improved gold recovery arising from adopting a finer crush size, indicating that the optimum crush size for all material from the Hamama West “gold oxide cap” will be -12.5mm.
The leach kinetics in Figure 1 show that both the oxide and transitional ore types exhibit fast gold leach kinetics with circa 65% of the contained gold extracted after 10 days of leaching. Furthermore ongoing leaching of gold continued throughout the testing period, with the gold recoveries from all samples still increasing up until the termination of the column tests after 70 days.
Lime consumption was very low and cyanide consumption considered to be moderately high.
Figure 1 – Column leach test curves based on back calculated gold head grade
About Aton Resources Inc.
Aton Resources Inc. (AAN: TSX-V) is focused on its 100% owned Abu Marawat Concession (“Abu Marawat”), located in Egypt’s Arabian-Nubian Shield, approximately 200 km north of Centamin’s Sukari gold mine. Aton has identified a 40 km long gold mineralized trend at Abu Marawat, anchored by the Hamama deposit in the west and the Abu Marawat deposit in the east, containing numerous gold exploration targets, including three historic British mines. Aton has identified several distinct geological trends within Abu Marawat, which display potential for the development of RIRG and orogenic gold mineralization, VMS precious and base metal mineralization, and epithermal-IOCG precious and base metal mineralization. Abu Marawat is over 738km2 in size and is located in an area of excellent infrastructure, a four-lane highway, a 220kV power line, and a water pipeline are in close proximity.
The technical information contained in this News Release was prepared by Gary Patrick BSc, MAusIMM, CP (Met), Principal Consultant of Metallurg Pty Ltd. Mr. Patrick is a qualified person (QP) under National Instrument 43-101 Standards of Disclosure for Mineral Projects.
For further information regarding Aton Resources Inc., please visit us at www.atonresources.com or contact:
President and Chief Executive Officer
Note Regarding Forward-Looking Statements
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