Resource remodelling by Aspire Mining at the Ovoot Coking Coal Project in northern Mongolia has resulted in a 23.7 million tonne, or 10%, increase to the open pit resource, which now stands at 253.1 million tonnes. The probable and marketable coal reserves have also increased.
The underground coal resources remain unchanged at 27.9 million tonnes bringing total JORC-compliant resources to 281 million tonnes with 197 million tonnes in the measured category, 72.3 million in the indicated category and 11.8 million in the inferred category.
The probable reserve tonnes have increased by 34 million tonnes to 255 million ROM at total moisture of 2%. The probable marketable coal reserve has increased by 8 million tonnes to 188 million tonnes at product moisture of 9.5%. The upgrades have confirmed that Ovoot is Mongolia’s second largest coking coal reserve.
During the Mongolian winter an extensive geological structural and seam reinterpretation of Ovoot’s open pit resource was undertaken by Aspire’s geological team. This has resulted in improved seam correlation and a reduction in seam PLY’s, comprising the upper, lower and OVB seams.
The improved consistency of the seams and structural interpretation gives increased confidence in the deposit and allows additional tonnage to be included in the geological model. A total of 96% of resources are now classified in the measured and indicated categories.
Meantime, Aspire has also demonstrated the quality of the coking coal from Ovoot after test work confirmed its superior blend carrying capacity. Importantly, blends of Ovoot coking coal with non-coking coal from the Government-owned Tavan Tolgoi (TT) mine in southern Mongolia displayed good coking properties.
“The very positive blending results of Ovoot and TT coals demonstrate the carrying capacity of Ovoot’s fat coal,” Aspire’s managing director David Paull says. “This also has the important benefit for Mongolia in being able to establish a new large and long-term revenue stream for this blended coal adding substantial value to the Tavan Tolgoi mine.”
The test work was carried out by Mongolian Independent Research Group that consists of professors from the National University of Mongolia and senior researchers from Mongolia’s Mining Research Laboratory. This found that coals from seams 0, 3 and 4 from the TT deposit that were blended with indicative coking coal from Ovoot resulted in a good quality coking coal with a Chinese classification of ‘Primary Coking Coal’ or ‘1/3 Coking’. Seam 0 is generally classified as thermal coal and samples from seams 3 and 4 were confirmed as oxidized coal with nil remaining coking properties.
Samples from these seams were washed to bring ash levels down to a targeted 10% and then combined with Ovoot coal on a 50/50 basis.
Over the next 20 years significant quantities of thermal coal and oxidized coking coal will be mined from TT. These are obvious blending partners for Ovoot project coal due to their similar rank and vitrinite categories. TT coals are low in sulphur whereas Ovoot project coking coal is high in caking and plastic properties necessary to produce coke.