Öksüt

Öksüt is Stratex's latest high-sulphidation (HS) gold discovery in Central Anatolia, located 25 km south of Develi and 70 km south of Kayseri. The 109.4 km² licence area is hosted within Miocene andesitic lava domes and pyroclastics, with units showing structurally controlled alteration, predominantly silicification and advanced argillic alteration.

Figure 1. Early drilling at the Ortaçam zone, looking to the south.

Under the terms of a joint venture agreement with Centerra, Centerra is currently funding exploration at Öksüt. Centerra has met its initial earn-in expenditure of US$3 million to gain 50% of the project, which included 4,600 m diamond drilling, and is now earning an additional 20% interest in the project by funding an additional US$3 million of exploration expenditures on the property within the next two years.

Following the 2010 drilling programme, a total resource of 317,256 oz Au was defined within two of the six key zones identified, the main Ortaçam zone (Fig. 1, Fig. 2, Table. 1) and the Ortaçam North zone (Fig. 2, Table. 2). Following the 2011 drilling programme, an increased resource of 1,047,872 oz Au, in the Indicated and Inferred catergories, was calculated by Wardell Armstrong International, including 563,085 oz oxide Au (Table. 5) that is likely to be amenable to open-pit mining and heap-leach recovery. 

Table 1. Ortaçam Zone Mineral Resource Estimate using a 0.2 g/t Au cut-off

Table 2. Ortaçam North Zone Mineral Resource Estimate using 0.2 g/t Au cut-off

Figure 2. Targets identified by rock-chip sampling at Öksüt.

To date, fifty-seven drill holes have been completed for a total of 13,835.10 m and the results are summarised in Tables 3, 4 and 5. Early drilling showed that the mineralization at Ortaçam is largely confined to steeply inclined breccia zones, with outcropping silica representing more extensive upper parts of breccia zones that taper at depth.

On-going drilling at Ortaçam North (Fig. 3) has confirmed that it comprises a number of relatively high-grade gold-bearing breccia pipes over an area of 350 metres x 250 metres, within a wider zone of less-well mineralised and altered breccia and volcaniclastic rocks up to 500 metres in diameter. Alteration and brecciation are estimated to extend down to a vertical depth of at least 420 metres. Best intersections include 268.00 m @ 2.34 g/t including 185.50 m @ 3.19 g/t and 59.20 m @ 5.39 g/t Au; 234.40 m @ 2.08 g/t Au, 220.20 m @ 1.83 g/t Au; 199.60 m @ 2.06 g/t including 60.30 m @ 4.7 g/t; and 116.00 metres @ 1.10 g/t Au.

The western and northern margins of the breccia pipe remain open and will be drill-tested, along with the wider licence area, during the 2012 drill programme, which is due to commence Q2-2012 (Fig. 4 and Fig. 5).

Intersections across this pipe are characterised by being predominantly oxide material, with only minor sulphide (mostly pyrite) present in some clasts of material resulting from the explosive brecciation of earlier mineralisation. Recent re-logging of the core, combined with the low sulphur contents determined by chemical analysis, reaffirm that the pyrite content is generally much less than 1%. Near-complete oxidation, extending down to at least 420 metres vertically, is likely to be an important factor in the future exploitation of the deposit.

Preliminary investigation of the leaching characteristics of the gold-bearing material was undertaken by submitting samples previously assayed for gold for repeat analysis using a cyanide-leach method. Oxide material containing no appreciable pyrite yielded recoveries averaging 92% and samples of transition material (containing minor pyrite) returned recoveries averaging 78%. Although this preliminary work can only be regarded as providing a general indication of possible recoveries and needs to be substantiated with detailed metallurgical test work in the future, the results do suggest that both oxide and transition material should be amenable to processing by heap leaching.

Table 3. First-phase drilling results

*All intersections are with cut-off grade at 0.2 g/t Au unless otherwise stated.

Table 4. 2010 drilling results

1 Length not necessarily representative of true thickness.

Table 5. 2011 drilling results

1 Length not necessarily representative of true thickness. 2 Includes minor sulphide in places

* ODD-33 - includes 10 m <0.2 g/t Au; ODD-35 - includes 3 m of mixed oxide-sulphide

Figure 3. Drill plan of the Ortaçam North Zone.

Figure 4. Provisional interpretation of Ortaçam North Zone: N-S cross-section

Figure 5. Provisional interpretation of Ortaçam North Zone: SW - NE cross-section