U URANIUM COMMODI TY I nsi ghts Bul l eti n My view is that uranium will break out of its holding pattern when a number of events combine from Japanese restarts, supply disruption and a return to long-term contracting. Derek Meates KPMG in Canada My view is that uranium will break out of its holding pattern when a number of events combine from Japanese restarts, supply disruption and a return to long-term contracting. The current holding pattern will continue for the medium-term given there is oversupply on the back of Fukushima. On a positive note, the uranium price remains steady, if not spectacular, unlike other commodities that have experienced significant recent price declines such as iron ore and copper. The uranium price is underpinned by strong long-term fundamentals given significant new build in China. However, uranium companies are not and would not expect to be immune to the present reality of the mining cycle with a focus on reduced capex, project deferrals, operational efficiency and some liquidity concerns.

Purpose. Increasing the efficiency of gold heap leaching by changing the solution rheological properties due to its mechanical activation. Semi-industrial tests were carried out to verify the results of laboratory work. Methodology. First, semi-industrial tests were carried out without activation of the solution (basic technology), and then the solution activation was applied. The ore amount in the stockpile was 600 kg; the gold content in the ore is 1.12 g/t. At the same time, the concentration of cyanide was 400 ppm. The activation degree was from 3 to 8 minutes, the leaching time was 2, 4, 6 hours, the solution temperature varied from 13 to 30 degrees. Findings. According to the results of semi-industrial tests, the dependence of gold content, pH value, and residual concentration of the reagent on the leaching time was obtained using both proposed technology and the basic one. Comparison of the semi-industrial test results related to the basic technology and proposed one (with the solution activation) showed that the maximum gold content in the productive solution with the basic technology is 1.83 mg/l, and with the activation of the solution it is 2.10 mg/l. Hence, there is an increase in the gold content by 14.7% with the solution activation Originality. Dependence of gold content in productive solution, pH value, and residual concentration of the reagent in solution on the degree of its activation has been obtained. Practical value. The optimum degree of the treatment solution activation during gold heap leaching is determined, which is from 5 minutes to 7 minutes depending on the leaching time, which increases the gold content in the solution by 14.7%.

The current goal in uranium mining is to ensure the maximum effect at minimized costs. One of the problems when using the in-situ leaching (ISL) technology consists in the incomplete mining of the process blocks due to premature uranium content reduction in the pregnant solutions, leading to increased mining times and excessive reagent consumption. The required complete block mining shall be ensured with the highest possible efficiency. The ISL technology is currently used for the mining of all hydrogenous uranium deposits in the Republic of Kazakhstan, which are often characterized by complex geological and hydrogeological conditions. One of these deposits, Semizbay, rates as complexity type III. The conditions at the deposit require increasing the redox potential of the solution by oxidizing Fe2+ into Fe3+. The article considers the addition of hydrogen peroxide to the leaching solutions to improve the redox potential with due account of the mining and geological features of the Semizbay deposit. The pilot tests have established that this oxidizing agent has a positive effect on the uranium content in the pregnant solution with the concentrations of 0.2–0.3 l/m3, provided that the concentration of sulfuric acid in the leaching solutions is within the range of 13–15 g/l. The studies allowed increasing the concentration of uranium in the pregnant solutions from 74 to 114 g/l (i.e., by over 50 %). The authors are grateful to the staff of the geotechnology department of the Semizbay mine, Semizbay-U LLP, for collecting the data and to the staff of the IVT-Zerde LLP laboratory (branch of the Semizbay mine) for the high-quality laboratory experiments during the pilot tests at the mine.