OPERATION FOCUS
both Cascavel and Sertão to over 700 m downdip ( 1,600 m at Sertão ) – and remains open .
Regionally , this high level of continuity is a common feature of the shear zone hosted gold deposits in the State , with both Anglo Gold Ashanti and Yamana Gold having multi-million ounce resources in similar structures .
Orinoco says “ the evidence for mineralisation in and around the Cascavel area gives the company great confidence that it can rapidly grow the potential of the Faina Goldfields project .”
Orinoco now holds 100 % of the Sertão Mining Leases , which include the former Sertão gold mine . The leases are located just 28 km by road from the Cascavel mine .
Sertão mine is located on an existing Mining Lease , and boasts historical production of 256,000 oz of gold at a grade of 25 g / t Au from a shallow open pit . It is located on the same shear zone as Cascavel , and offers outstanding potential for the delineation of additional highgrade coarse gold mineralisation similar to that found at Cascavel .
Drilling undertaken by previous owners identified material depth and strike extensions to the mineralisation at Sertão . A review of existing drill data from zones outside the Sertão
open pit shows that a total of 176 holes were drilled outside of the mined areas at Sertão where previous mining targeted shallow oxide material to a depth of just some 40 m .
Orinoco completed its maiden drilling program at Sertão in late 2015 . The best results from the 2015 drilling of the Mining Lease include :
■ 0.5 m @ 7.33 g / t ( STO _ 004 : from 141.5-142.0 m )
■ 1.82 m @ 13.55 g / t ( STO _ 005 : from 130 m )
■ 0.65 m @ 13.05 g / t ( STO _ 005 : from 126.2 m )
■ 0.46 m @ 21.40 g / t ( STO _ 005 : from 131 m )
■ 0.5 m @ 46.8 g / t ( STO _ 022 : from 150.2 m ) The new results combined with information from historical drilling show that some oxide ore remains at Sertão as well as highlighting significant extensions of the mineralised zone . A review of historical data and geological interpretations at Sertão indicates very similar structures to those seen at Cascavel , including rod-shaped high grade shoots located within a broader mineralised zone . The mineralised quartz veins at Sertão are hosted by the same low-angle shear zone structure that hosts the Cascavel veins , located approximately 18 km northwest along strike .
In October 2014 , Orinoco materially increased the size of the Cascavel project after securing a
70 % interest in the highly prospective Espaňola prospect – a nearby tenement with known gold mineralisation .
The tenement is situated immediately to the north of both the Cascavel gold and the Central Tinteiro polymetallic projects . It contains significant northwest extensions of both the Cascavel and Tinteiro geological trends , extending the known Cascavel structure by 60 % to approximately 4 km of strike .
And the third prospect , the Tinteiro IOCG ( iron oxide , copper , gold ) is located in the central portion of the Faina Greenstone Belt , 4 km to the southwest of Cascavel . It was discovered in May 2013 , when Orinoco discovered high-grade silver and base metal mineralisation in the footwall of the Mestre zone and over the hanging wall of the Cuca zone gold lode at Cascavel .
Significant silver and base metals assays announced previously from drilling around the Cascavel area include :
■ CDP _ 025 : 25.0 m @ 39.2 g / t Ag : including 3 m @ 97.2 g / t Ag from 114 m
■ CDP _ 031 : 4.4 m @ 760.3 g / t Ag : including 1.05 m @ 2,510 g / t Ag from 157 m
■ CDP _ 014 : 4.7 m @ 58.6 g / t Ag : including 0.85 m @ 236 g / t Ag from 162 m
■ CDP _ 021 : 17.6 m @ 1,292 g / t Ag & 11 m @ 0.25 % Cu , 16.41 m from 101 m . Subsequent geological mapping in the
Cascavel exploration decline has shown that the high-grade silver and base metal mineralisation is related to the intersection of a series of northeast trending faults and a dolomitic unit in the footwall of the main Cascavel gold structure .
The northwest trending structures offset and therefore post-date the main gold-bearing structure indicating that these are two separate mineralising events potentially separated by millions of years .
In May 2014 , rock chip samples confirmed that this mineralisation extended up to 4 km away into the Tinteiro prospect , potentially indicating the presence of a large IOCG system .
Orinoco undertook a reconnaissance drilling program at Tinteiro in September 2014 , which provided further evidence of a widespread mineralised polymetallic system at Tinteiro . Assays show that the fault zones are mineralised and are indicative of an alteration halo in the upper portions of an extensive mineral system .
The continuing success of exploration within the Tinteiro system , and the expanding size of the target areas have attracted interest from several mining companies , including majors , who are currently conducting due diligence on the Tinteiro Project with a view to potentially partnering with Orinoco on future exploration of the Tinteiro system . IM
26 International Mining | SEPTEMBER 2016