The study has demonstrated that the La India Open Pit will support pit wall angles varying between 40 and 48 degrees, an improvement in the 40 to 42 degree angles assumed in the Preliminary Economic Assessment ("PEA").
Mark Child, Chairman and CEO commented: "The results of the geotechnical report to the Pre-Feasibility Level of confidence are encouraging. The pit angles range from 40 to 48 degrees and are an improvement on the 40:42 degree pit angles used in the Preliminary Economic Assessment released in March 2013. Steeper pit angles may allow the open pit to be pushed deeper and reduce the strip ratio of waste rock to mineralised ore, thus improving economics. This is particularly significant to La India Project as 432,000 oz gold at 4.9g/t sits beneath the current open pit resource of 954,000 oz gold of 3.6g/t. It is also noted that the PEA used a smaller pit containing 800,000 oz gold. An improvement in pit angles could drive the pit deeper, so that circa 1 Million oz gold open pit resource could be used in the next mining study.
Furthermore, it is likely that the pit angles with be improved/optimised further once hydrogeology studies are completed, which include hydrogeological drilling to determine the dewatering characteristics of the open pit."
Summary of Geotechnical Study Findings for La India Vein Set Resource La India Vein Set hosts a mineral resource of 12 Million tonnes at 4.0g/t for 1.5 Million oz gold, as announced in September 2012. Over 60% of the resource is contained within an optimised open pit shell derived using Whittle pit modelling software for an open pit resource of 8.21 Million tones at 3.6g/t for 954,000 oz gold. There is a further 2.77 Million tonnes at 4.9g/t for 432,000 oz gold underground resource beneath the La India Open Pit resource. A PEA based on the September 2012 resource data suggested that an 800,000 oz gold open pit was potentially feasible using a conservative assumption of 40-42° pit slope angles as no geotechnical or hydrogeology work had been undertaken. The geotechnical study was undertaken to provide a more accurate model of the slope angles that can be supported by an open pit, to a level of confidence that can be used in a future PFS.
Geotechnical Study Data
The geotechnical study was planned and overseen by SRK Consulting (UK) Limited ("SRK") and completed to PFS level of confidence incorporating data from:
– Geotechnical mapping of surface outcrops and old mine workings.
– Geotechnical core logging by an SRK consultant of 11 geotechnical drill holes for 1836m, supplemented by geotechnical logging of 12 selected resource drill holes for a further 2550m.
– Measurement geo-mechanical properties of over 400 samples completed both on-site and in specialist geotechnical laboratories in Nicaragua and the United Kingdom.
– Groundwater data collected from 13 existing wells and mine shafts, supplemented by 6 piezometers installed in selected geotechnical drill holes, including hydraulic conductivity data collected using falling head tests on three selected drill holes.
– 3-Dimensional geological mapping of rock types, geological structures and weathering horizons.
The analysis and interpretation of geotechnical data has been completed. La India Open Pit area has been divided into eight geotechnical domains, four in the hanging wall and four in the footwall zones, each of which will support different pit wall angles reflecting variations in properties such as the rock strength and the frequency, pattern and form of natural joints, fractures and faults in the rock. Pit slope angles vary between 40 degrees at the northern end of the open pit where the gold mineralised Arizona Vein cross-cuts the La India Resource, and 48 degrees between the 600-1200 cross sections where the bulk of the gold mineralisation is contained and the pit will be deepest.
Resource Update
Further to the completion of 23,600m drilling on La India Project since the September 2012 resource announcement, a resource update is currently underway and due by the end of October 2013. 13,956m of this drilling campaign was in La India Open Pit area focused on converting the gold resource from inferred to indicated category within the entire 954,000 oz open pit resource and part of the 432,000 oz gold beneath the open pit resource. The steeper pit walls will reduce the amount of waste rock that needs to be moved, improving economics and opening the possibility of mining deeper than previously envisaged using open pit methods.
