our pan-Ecuadorian Strategy
A comprehensive, nation-wide desktop study has been undertaken by SolGold's independent experts to analyse the available regional topographic, geological, geochemical and gravity data over the prospective magmatic belts of Ecuador, with the aim of understanding the controls to copper-gold mineralization on a regional scale. SolGold has delineated and ranked regional exploration targets for the potential to contain world class copper-gold deposits.
As a result of this study, SolGold formed and initially funded, four new 100% owned subsidiary companies in Ecuador; Carnegie Ridge Resources S.A., Green Rock Resources S.A., Cruz del Sol S.A. and Valle Rico Resources S.A.
These subsidiaries currently hold 77 mineral concessions over approximately 3,248km2.
The objective of these subsidiaries is to apply the exploration blueprint developed at Cascabel to discover more porphyry copper-gold deposits in Ecuador. Each subsidiary deals with a geographic region of Ecuador. Each subsidiary company has technical teams, led by experienced senior geologists, on the ground prospecting granted tenements and collecting baseline data, whilst regional geophysics surveys are being planned. Significant copper occurrences have been identified at numerous projects to date, including La Hueca, Machos, Rio Armarillo, Sharug, Porvenir and Timbara.
The teams are focussed on first pass exploration on the Porvenir, San Antonio, Sharug, Machos, Agustin and Rio Amarillo projects. Initial mapping campaigns have been very encouraging with widespread areas of hydrothermal alteration identified which are considered highly prospective for porphyry and epithermal style mineralisation. Initial rock chip samples taken of altered outcrops have returned values as high as 12% Cu. Regional geology teams are commencing systematic stream sediment sampling and panned concentrate programs over the prospective tenements. From the stream and panned concentrate results, gridded soil programs will be planned to identify targets to be drilled in due course.
Cruz del Sol S.A
In October 2017 SolGold announced an exciting new copper discovery in southern Ecuador, La Hueca, after several months of conducting reconnaissance sampling, mapping and prospecting by field teams.
A strike length of 25km of prospective copper gold porphyry targets has been developed on the basis of outcropping mineralisation, strong stream sediment anomalism for copper and gold, and strong panned gold and magnetite concentrate results.
Results from initial stream sediment and pan concentrate sampling in the La Hueca tenement area have identified several areas of interest known as the El Cerro Florida Naquipa and Eduardo prospects from north to south. Streams over a 6km x 4km zone draining the area of interest were ubiquitously rich in gold and magnetite indicating the prevalence of the copper gold mineralised porphyries in the area. The first stream anomaly followed up was recognised as exhibiting significant potassic and propyllitic alteration and mineralisation indicative of the presence of a large porphyry system. Detailed mapping and rock chip sampling was carried out to determine the extent of the alteration system. The results are detailed in Table 1 outlined below.
A northeast - southwest striking quartz stockwork was identified and mapped over a 5km length that remains open along strike northwest and southeast, and lies within an altered corridor several kilometres wide comprising mostly diorite host rocks. The most significant zone mapped so far within this diorite hosted quartz stockwork corridor displays very strong alteration and mineralisation over an area 700m long by 450m wide, characterised by with a multidirectional quartz vein network containing diagnostic copper gold porphyry minerals including notably chalcopyrite, bornite, molybdenite and magnetite associated with chlorite, sericite and epidote alteration. This zone has returned the highest grade copper and gold results.
Strong molybdenum mineralisation evident as molybdenite is ubiquitous in the La Hueca system and SolGold's technical advisors have opined that this indicates a substantial porphyry system sourcing mineralisation from a deep seated and strongly metal endowed batholith. SolGold believes that this is a favourable indicator for the ultimate size and grade of the system being explored at La Hueca.
Detailed mapping and sampling of the stockwork corridor continues with several new areas of strong alteration and mineralisation recently reported by the field teams to the northeast, southwest and west. In addition, several large geochemical stream anomalies outside of the stockwork corridor have been identified at the La Hueca Project that are yet to be investigated by SolGold's field teams.
An extensive stream sediment and panned heavy concentrate sampling program was recently completed throughout all La Hueca tenements. The results confirm the 25km long corridor of gold and copper anomalism running through the project. Five geochemical anomalies where selected for priority follow-up prospecting (Figure 2). With these new discoveries in Targets 2 & 3, mineralised outcrops have been successfully located in all 5 targets selected from SolGold's geochemical sampling programs.
Samples were taken from a fault-clay gouge breccia of a diorite. Samples were taken over a strike of 250m with all samples returning high copper values. Whilst the breccia is relatively narrow, around 8m wide, it is strongly mineralised and interpreted to represent a deep structure that has exhumed heavily mineralized blocks belonging to a deeper mineralised porphyry system.
The fault breccia strikes 250° and dips 20°-30° representing a reverse thrust. It consists of sub angular - sub-rounded pale cream clasts with diameters up to 3cm. K-feldspar-biotite-carbonates-epidote altered intrusive is present in the fault proximity. It is commonly darker coloured due to fine grained graphite and sheared sulphide minerals. Quartz-chalcopyrite veins are present in restricted sections where chalcopyrite occurs up to 5%. Alteration consists of intense chlorite-epidote-sericite in the diorite. The biotite alteration appears to have replaced the mafic minerals (hornblende) in medium-grained diorites; this occurs with moderate intensity.
In the rich sections of stockwork quartz veinlets, sugary type B and magnetite veinlets were identified. In addition, rock sample mineralization to 5% chalcopyrite, bornite 2%, 1% chalcocite, traces of malachite and native Cu.
The outcrops sampled in Target 3 represents an exposed 5m thick quartz vein containing pyrite, chalcopyrite, bornite, and minor chalcocite. Surrounding the vein are outcrops containing abundant magnetite veinlets cut by quartz veins containing chalcopyrite, magnetite, pyrite and minor chalcocite. The dominant hydrothermal alteration in this area consists of chlorite-epidote. The quartz vein samples generally returned values between 0.3 - 0.6% Cu with a nearby sample of float returning 3.52% Cu and 0.97 g/t Au.
Future Work at La Hueca
The La Hueca Project represents an exciting new project with multiple mineralised targets located within a 25km porphyry corridor. Along with continued field prospecting, planning is underway to conduct 3D geochemical modelling to model target depth. Various geophysical methods are also being considered.
All updates regarding the La Hueca Project are available here
Green Rock Resources
The Green Rock Resources team discovered the Porvenir Project and the Timbara Project in November 2017. Both projects are located in southern Ecuador, along trend, southwest of Santa del Cruz’s La Hueca Project. The projects are hosted in Ecuador's eastern Jurassic Belt, which contains the Fruta del Norte epithermal gold deposit (14 million ounces gold), the Mirador copper porphyry deposit (3 million tonnes copper) and the Santa Barbara gold-(copper) porphyry deposit (8 million ounces gold).
A stream sediment sampling program at the Porvenir Project delineated two geochemical anomalies within the larger 6km x 5.5km stream anomaly, the Derrumbo and Bartolo prospects (Figure 2). Initial follow-up stream reconnaissance rock chip sampling returned very high copper results of up to 4.27% Cu from the outcrop samples on the Bartolo prospect and significant copper results of up to 0.8% Cu were returned from the Derrumbo prospect.
Copper mineralisation in the porphyry outcrops is related to chalcopyrite content with associated chalcocite - covellite - magnetite. Three main hydrothermal alteration styles can be distinguished at the Porvenir:
- Early-stage alteration defined by magnetite-rich and sulfide poor zones with abundant epidote veinlets and disseminations;
- Chlorite -sericite alteration related to the main mineralised stage; and
- Late-stage, strong quartz-sericite-pyrite alteration.
The next phase of exploration at Porvenir will comprise auger soil geochemistry to delineate drill targets. Additional specialist soil sampling teams are being readied to begin this work. The soil teams will collect samples for both multi-element geochemistry and ASD analysis. Results of the soil programs will be used to design future drilling programs. An aeromagnetic survey is planned over the Porvenir Project.
All updates regarding the Porvenir Project are available here: http://www.solgold.com.au/announcements/
Field teams have recently started first pass evaluation activities on one of four Timbara Project tenements (Figure 6). During a targeted program of stream sediment and panned heavy concentrate collection, rock chip samples were collected of notable mineralised outcrops. Whilst the results of the stream sediment samples are still awaited, assays from the initial rock samples have been returned. Results are very encouraging for both porphyry and peripheral skarn style mineralisation distal to the porphyry host.
Outcrops of porphyry style copper mineralisation typically comprise vein and disseminated chalcopyrite, pyrite with traces of bornite. Associated hydrothermal alteration is characteristically sericite and chlorite. Skarn style outcrops are generally highly fractured with quartz veins and epidote alteration present. Sulphides in these outcrops comprise chalcopyrite, occurring with magnetite, galena and pyrite.
Whilst detailed sampling and mapping is required, early results suggest a potential mineralised NE-SW trend of 4.5km with anomalous outcrops suggesting a system corridor, variably altered and mineralised, between 1.2km and 1.5km in width. Results from the stream geochemical sampling will help establish the extent and trend of this newly discovered copper prospect in the Timbara 2 tenement.
Field teams are currently focussed on first pass evaluation of the remaining three Timbara Project tenements. Once the stream sediment and panned heavy concentrate programs have been completed and results are returned, field teams will transition to targeted systematic mapping and rock chip sampling of anomalous streams to gain a better understanding of the geological controls, hydrothermal alteration and style of Cu mineralisation at Timbara. An aeromagnetic survey will also be carried out over the Timbara Project.
All updates regarding the Timbara Project are available here: http://www.solgold.com.au/announcements/