Sudan – The aquifer system, located over an area covering approximately 13 km2, was discovered as a result of an ongoing water exploration programme at Block 14.
Orca Gold believes that the aquifer system defined to date has the potential to supply +30 million cubic meters of water to the Block 14 project – with the potential to expand the discovery to the north, east and south.
Orca Gold president and CEO Hugh Stuart notes that water is a major factor in the development of a gold mine, particularly in a desert environment – such as the Block 14 gold project.
“The results of this latest water exploration programme go a long way towards ticking that box,” he says.
The aquifer system was discovered as part of a follow up drill programme following geophysical surveys completed in late 2015. The drill programme aimed at testing two low resistivity anomalies hosted within the Cretaceous Nubian Sandstone basin just north of Block 14.
The aquifer is located within the first geophysical anomaly (HA8), and is located 50 km north of the Galat Sufar South (GSS) Resource, where a single borehole drilled in 2014 had intersected water bearing sandstones.
Six follow-up drill holes were completed on HA8, of which four of these six new boreholes have intersected numerous water bearing layers between depths of 34 m and 148 m within an interbedded sequence of course grained sandstone and sandy clays.
The Nubian Sandstone sequence at HA8 consists of multiple layers of coarse-, medium- and fine-grained sandstone bounded by layers of mudstone, siltstone and clay.
Water strikes are related to a number of course- and medium-grained sandstone units within the sequence. The combined average thickness of these water bearing units is between 16 m and 20 m, while secondary water bearing horizons may also be contributing to the water flow.
The water resource will soon be subject to a more detailed phase of pump testing and confirmation of aquifer characteristics, but Orca Gold considers the discovery and scope of the aquifer identified at HA8 as a major milestone in the development of Block 14 as a commercially viable project.
Meanwhile, the latest water drilling programme, currently underway, is testing a second geophysical anomaly (HA9), located closer to the GSS Resource.
Upon completion of the drill programme at HA9, the rig will return to HA8 to test the deeper levels of the sequence.
A new water programme will then be budgeted towards determining aquifer hydraulics and potential production rates.
Solid high-grade resource
Orca Gold has defined an indicated resource of 27.6 Mt grading 1.83g/t for 1.63 Moz of gold and an inferred resource of 10.3 Mt grading 1.8g/t for an additional 0.6 Moz of gold (based on a 1g/t cut-off grade at the Galat Sufar South and Wadi Doum prospects on Block 14.
Mineralisation is robust with true widths up to 85 m and >75% of resources within 150 m of surface.