ECR through its wholly owned Australian subsidiary Mercator Gold Australia Pty Ltd ("MGA") is focused on delivering the next multi-million ounce gold resource in Australia.
In recent years, MGA's exploration activities have been concentrated in the state of Victoria. Its tenement position in Victoria is detailed in the table below and in the figure to the left.
The Bailieston project is targeting epizonal or epithermal gold mineralisation of the Melbourne Zone, which hosts successful modern gold mines including the world-class Fosterville gold mine owned by Kirkland Lake Gold.
The Bailieston project is at the epicentre of the current gold exploration boom in Victoria, being located close to the highly successful Fosterville mine owned by Kirkland Lake Gold. This point is underlined by the arrival of Newmont Exploration in the district with an application for ground immediately to the north of the Black Cat prospect.
Bailieston is located approximately 150km north of the Victorian state capital Melbourne, with good road access. The project is located geologically within the major orogenic Lachlan Fold Belt (LFB). The LFB is subdivided into zones, based on distinct geological and metallurgical characteristics, with the Bailieston project lying to the east, within the Melbourne Zone.
The project area consists of Siluro-Devonian sediments intruded by Devonian granite stocks. Mineralisation is hosted by vein or stockwork structures, typically within anticlinal trap structures within the sediments.
The Bailieston area has a modest historical production history from alluvial and vein quartz mines. It has a more recent history of exploitation of low-grade, bulk mining stockwork or layered vein structures such as the Bailieston open cut mine which was operated by Perseverance Corporation Ltd in the 1990s.
Other modern nearby open cut gold operations which operated include Hill 158 at Nagambie, Red Hill at Heathcote and the various pits at Fosterville and Costerfield. These latter two continue to operate as higher-grade underground mining operations. The Fosterville mine is located approximately 50km west of the Bailieston project.
Significant intersections from Q1 2019 reverse circulation (RC) drilling by MGA at the Blue Moon prospect within the Bailieston project area included 2 metres at 17.87 g/t gold from 57 metres down hole in BBM007 within a zone of 15 metres at 3.81 g/t gold from 51 metres, and 3 metres at 3.88 g/t gold from 170 metres down hole within a zone of 11 metres at 2.42 g/t gold from 169 metres in hole BBM006. These intersections are apparent width. The results of this programme have confirmed Blue Moon as a new gold discovery within the Bailieston project area. More details regarding the drilling can be found here.
There is a gap in the historical workings from the HR3 area for approximately 800m to Cherry Tree to the south and for approximately 400m to the tenement boundary to the north, and there is potential in these zones for undiscovered mineralisation, particularly at depth.
The main Black Cat reef comprises a series of en-echelon quartz lenses within a shear zone, as is found at various other reefs within the Redcastle goldfield. Apart from quartz veined material that was mined historically, there exist siliceous pyritic sandstones and heavily fractured limonitic siltstones that can also be auriferous.
In Q1 2019, MGA completed a reconnaissance rotary air blast (RAB) drilling programme targeting numerous quartz reefs at Black Cat, with a total of 18 shallow holes for 485 metres being drilled. The prospect had never been drilled before. RAB drilling is a low-cost method well suited to the first pass, reconnaissance testing required at the Black Cat gold prospect.
Significant intersections from the drilling included 7 metres at 1.76 g/t gold from 35 metres in BCD11, 3 metres at 4.26 g/t gold from 16 metres in BCD18, and 1 metre at 6.3 g/t gold from 18 metres in BCD03. Intersections in this paragraph are apparent width. More details can be viewed here.
Important geological insights were generated by the drilling programme, which will guide further exploration at Black Cat and other prospects in the Bailieston gold project area.
The geochemical surveys utilised a portable XRF to delineate proxy minerals associated with gold. An arsenic anomalous zone up to 40 metres wide and more than 200 metres long was identified at Blue Moon, and previous work showed anomalism over a further 150 metres to the west. Previous rock chip samples included results of 12.1, 10.1 and 7.0 g/t gold, and previous soil surveys identified gold to 5.0 g/t. The diamond drilling at Blue Moon was intended to test the arsenic and antimony anomalies identified by the soil geochemical survey completed by MGA in early 2018.
Positive results from the drilling were announced in July 2018. Diamond drill holes BBM001 and BBM002 were designed to establish the dip of the host sandstones and assess the potential for gold mineralisation. Upon drilling faulted, stockworked sandstone in the first two holes, BBM003 was drilled down dip to test the nature of the cross-cutting faults and veins and to obtain a large number of samples for analysis. An intercept of 39.5 metres at 0.3 g/t gold from 24.2 metres, including 2.7 metres at 1.12 g/t gold from 60 metres, was obtained in BBM003. Intersections given in this paragraph are apparent width.
Given the deep weathering and the potential for gold depletion in the oxidised sulphides, it was considered possible that higher grades would be encountered at depth in the fresh (un-weathered) rock. Obtaining samples from fresh rock was a key objective of the reverse circulation (RC) drilling completed at Blue Moon in February 2019. The twelve RC holes (BBM004-15, for 1,718 metres in total) aimed to intercept the sandstone on 50 metre spacing across three sections and to gain samples from beneath the oxide zone.
The RC drilling programme returned significant intersections of gold mineralisation in nine holes (please see announcement here). Based on the results of this programme, together with other exploration as summarised above, Blue Moon constitutes a new gold discovery within the Bailieston project area. Significant intersections from the Q1 2019 RC drilling included 2 metres at 17.87 g/t gold from 57 metres down hole in BBM007, within a zone of 15 metres at 3.81 g/t gold from 51 metres, and an intersection of 3 metres at 3.88 g/t gold from 170 metres down hole within a zone of 11 metres at 2.42 g/t gold from 169 metres in hole BBM006. Intersections given in this paragraph are apparent width.
Gold mineralisation at Blue Moon is associated with sandstone plus dykes intruding the sandstone and adjacent to it. Sericitic alteration, silicification, sulphide development and gold mineralisation are restricted to the host sandstone with rare sulphides developed in the dykes. Quartz is generally low to absent, even in drill hole BBM007 where quartz was estimated at up to 2% and arsenopyrite at up to 1%.
The RC drilling results indicate that the host sandstone is thicker and the gold grades significantly higher on the westerly section, and further exploration will therefore seek to follow the system to the west, subject to agreeing access with landowners. Further exploration to the west would initially comprise surface geochemical sampling, potentially followed by drill testing.
The Avoca project is centred on mesothermal quartz vein hosted gold and related placer-style ‘deep lead’ gold mineralisation. There is a considerable local history of mining both kinds of deposit. The term ‘deep lead’ refers to buried auriferous river bed deposits.
The Avoca project is located approximately 183km west northwest of the Victorian state capital Melbourne, with good road access. The project is located geologically within the major orogenic Lachlan Fold Belt (LFB). The LFB is subdivided into zones, based on distinct geological and metallurgical characteristics, with the Avoca project lying to the west, within the Stawell Zone.
Having previously been mined with a significant amount of gold production from both alluvial and hard rock high grade sources, ECR considers the Avoca project is highly prospective for hard rock structurally controlled gold deposits.
The hard rock historic mines within the Avoca licence include the high grade:
* Pyrenees Reefs - 16,199 tons mined for 16,602 oz Au to 130 meters at an average recovered grade of 32g/t Au, worked from 1860 to 1912.
* Excelsior Reef - 13,200 tons mined for 9260 oz Au to 100 meters at an average recovered grade of 22g/t Au, worked from 1909 to 1915.
* Monte Christo Reefs – 2,795 tons mined for 937 oz Au to 30 meters at an average recovered grade of 10.3g/t Au, worked from 1872 to 1877.
There are numerous historical shafts at the Surprise prospect and noteworthy historical (late 1990s) drilling results (including 2m @ 3.27g/t Au from 18m in SPAC04 and 5m @ 1.4g/t Au from 26m in SPAC06). The presence of molybdenum with gold in breccia raises the conceptual possibility of a high tonnage porphyry deposit.
The Creswick project is considered highly prospective for gold mineralisation hosted within the Dimocks Main Shale (the "DMS"), which extends over a 15km trend from the mining centre of Ballarat to the south, approximately 7km of which is covered by MGA’s granted exploration licence and exploration licence applications.
In the project area, the DMS is an approximately 25 m wide shale containing bedding- and cleavage-parallel auriferous quartz veins. The width of the shale and the occurrence of multiple veins in some zones indicates that potential open pit mining targets may present themselves as exploration progresses. Almost 1,500 shallow primary workings have been mapped in the belt from North Ballarat to Spring Hill (Creswick).
The DMS is the source of much alluvial and deep lead gold. Historical alluvial production is estimated at up to 2.5 million ounces in the Creswick/Berry lead system, and up to 11 million ounces in the Ballarat area as a whole, of which the DMS is a significant contributor.
MGA completed 1687m of reverse circulation (RC) drilling at Creswick in February 2019 for 17 holes. On 8 May 2019, ECR announced that the majority of the drill results had been received, with grades in nine holes ranging from 0.6 g/t gold to 44.63 g/t gold.
The mineralisation has been confirmed as nuggety, which can lead to understated or overstated assays; accordingly, a process of whole-of-bag gravity concentration tests on the RC drill samples was completed in 2019. For more information, please see ECR's 5 November 2019 announcement.
The Timor project area contains numerous hard rock and alluvial gold deposits evidenced by significant historical workings, and is located adjacent to the Avoca project.
Historical production from some 28 historical ‘deep lead’ alluvial mining operations within the Timor project area is believed to have been in the region of 640,000oz gold in total.
In addition, around 20 hard rock workings can be considered to have been significant producers. These include the Leviathan group of mines, which are believed to have yielded in excess of 67,500oz gold from 181,000 tonnes of ore, equating to a recovered grade of approximately 11.5g/t gold.
The most significant alluvial producer was the Duke & Main Lead Consols operation, located directly ‘downstream’ from the Leviathan hard rock mines.
The Moormbool project area covers an area linking the Redcastle and Graytown goldfields east of a large regional fault.
MGA interprets that if this is an intrusion, it may be genetically linked to the source of the gold mineralisation and a good target for exploration.