- Golden Age underground mine has generated strong cash flows for the last 3 quarters.
- Approximately 180Koz @ 9g/t Au has been historically mined from Golden Age Middle area.
- Successful drilling confirms that Golden Age mineralisation is open both down and down dip, with mining to increasingly target the extensions defined from this drilling
- Drilling of Golden Age Lower Extensions located mineralisation 150-300m below the current mining levels:
o 6.9m @ 15.5 g/t Au 107 g*m GARD0033
o 2.0m @ 11.8 g/t Au 23 g*m GARD0036
- Surface drilling at Golden Age North has intersected high grade shallower mineralisation amenable to both open pit and underground mining:
o 2m @ 28.3g/t Au from 75m 57 g*m WURC0577
o 6m @ 7.97g/t Au from 106m and 1m @ 6.14g/t Au 54 g*m WURC0583
o 8m @ 5.82 g/t Au from 87m 47 g*m WURC0579
o 7m @ 1.52 g/t Au from 12m and 14m @ 1.26g/t Au 28 g*m WURC0601
o 7m @ 2.97 g/t Au from 80m 21 g*m WURC0567
o 4m @ 4.24 g/t Au from 94m 17 g*m WURC0575
- Infill drilling has further extended remnant mineralisation currently being mined:
o 2.1m @ 43.6g/t Au and 1.1m @ 7.28g/t Au 97 g*m GAGC0244
o 6.5m @ 8.88g/t Au and 2.8m @ 5.81g/t Au 74 g*m GAGC0243
o 5.1m @ 4.15g/t Au 21 g*m GAGC0233
o 1.1m @ 17.4g/t Au 19 g*m GAGC0238
o 2.1m @ 7.87g/t Au 16 g*m GAGC0241
- Golden Age drilling programme to be extended further with a view to both lengthening the mine plan and increasing the mining rate at Golden Age.
- Free milling resources and reserves are currently being updated to incorporate recent Wiluna and Golden Age drilling success.
Milan Jerkovic, Executive Chairman said "Blackham is pleased to announce new drill results from our high-grade Golden Age orebody which have identified significant extensions to mineralisation within 200m of existing underground development. Based on the highly encouraging intercepts, planning has commenced for further drilling to better define the mineralised extensions and to support early underground development to provide additional high-grade ore to feed the Wiluna gold plant, which last quarter produced 20,631oz @ AISC A$1,092/oz".
Background and Programme Details
The Golden Age Underground mine is accessed via the Bulletin portal located only 2.5km from the 1.8Mtpa Wiluna gold plant. The Golden Age workings commenced in the 1890's and approximately 180,000oz @ 9g/t gold has been produced to date, with strong cash flows generated for the Company in the last three quarters. The discontinuous nature of the reef in places led to previous miners not accessing gold mineralisation in some areas previous mined. Recent mining of these remnant areas, armed with a greater understanding of the style of mineralisation, has produced additional gold from Golden Age over the past year. With the orebody now better understood, and the mineralisation open both down dip and down plunge, mining will increasingly target the extensions defined from this drilling.
Drill targets were aimed at maintaining a minimum 6-12 month mine life at Golden Age and to subsequently significantly increase mine capacity for the Golden Age mine area. The targets were arrived at following extensive data collation (including additional structural mapping) and a review of the stratigraphic sequence, deformation and mineralising events. Most of the drilling was aimed at defining extensions to the east and below the zone of mineralisation currently being mined. Grade control drilling in the remnant mining areas (at higher RLs) targeted areas where over-lapping, but separate, quartz lodes were previously missed; these remain viable mining targets.
Golden Age Lower Extensions
A 2,464m diamond drilling programme is underway targeting depth extensions to Golden Age (see Figure 2 in link below).
Initial drilling has returned highly successful results from the four holes drilled to date (730m), extending the zone of high grade mineralisation 150m below the current workings. The program specifically targeted an area interpreted to be a shallower dipping, dilational zone, preferential for the deposition of gold mineralisation.
All holes intercepted the strongly sheared Golden Age dolerite host rock and Golden Age quartz reef with three intercepts exhibiting the dominant galena and pyrite sulphide mineralisation typically associated with high grade zones. Reef intercepts varied from 1.2 - 6.9m in width with visible gold noted in one hole (GARD0034). Results received for these holes are:
6.9m @ 15.5 g/t Au 107 g*m GARD0033 (see Photo 1 of core tray) (see link below)
2.0m @ 11.8 g/t Au 23 g*m GARD0036
3.0m @ 2.11g/t Au 6 g*m GARD0034 (visible gold in core- see Photo 2 in link below).
The results strongly support the potential for the continuation of underground mining at Golden Age and further drilling is now being planned (to commence in Jul-Aug'18) to establish an initial resource in this area. Positive results may provide the catalyst for early access via the nearby Calais Decline to enable a substantial increase in the mining rate.
The on-going drilling will also test this zone at greater depth (a further 120m lower) to enable early assessment for a significant additional resource increase.
Recent assay results from Calais Decline sampling.
Recent results from sampling the Calais Decline on both the 825 RL and 800 RL have confirmed the high grade Golden Age Lower reef intersects the walls of the decline (see Figure 2, Photos 3 & 4 in link below). Four samples were taken across the 3.5m vein in the decline at the 825RL. The results included: 11.03 g/t, 6.86 g/t, 1.42 g/t and 0.25 g/t Au.
Four samples were also taken across the 1.8m vein in the decline at the 800RL. The results included: 0.82 g/t, 0.24 g/t, 22.3 g/t and 0.93 g/t Au.
Historical drilling has confirmed high grade mineralisation in AWD0502 (12.9m @ 6.88g/t Au) and APX012312 (7.4m @ 7.56g/t Au) 200m below where Blackham is currently mining on the 858RL, and 200m east of the Calais Decline (see Figure 2 in link below).
Recent drilling has now confirmed high grade mineralisation 200m east of where these Calais Decline samples were taken in GARD0033 (6.9m @ 15.5 g/t Au) and GARD0036 (2.0m @ 11.8 g/t Au).
Golden Age Lower has never been mined as it is offset from Golden Age Middle zone by a barren dyke. Golden Age Lower currently has a small resource of 168,000t @ 4.72g/t for 25,000oz (74% inferred). When the latest drill and face sampling results are combined with historical drilling it creates a very significant exploration target for Golden Age Lower all within 200m of existing access.
Blackham's geologists are currently planning additional drilling with a view to bring Golden Age Lower into the mine plan as a priority and to supply further high grade ore to the Wiluna gold plant.
Golden Age North
The Golden Age North prospect is situated immediately north and along strike of the historically mined Golden Age pit, on a NW-SE-striking reef structure that dips at approximately 70deg to the SW. Mineralisation is localised at the contacts of quartz-dolerite, tholeiitic basalt and intermediate porphyry rocks, with the best grades often associated with thick quartz veining.
Historical drilling, together with recent exploration drilling completed by Blackham has confirmed the continuity of the mineralised structure over a 600m strike and to a depth >150m, with mineralisation remaining open, both laterally and down-dip. Preliminary metallurgical test work indicates mineralisation at Golden Age North is also free-milling and is therefore considered an attractive feed for Blackham's Wiluna CIL processing facility, located only 2km away.
Drilling comprised of 19 holes for a total of 2,117m and was successful in intersecting high grade mineralisation over 600m of strike.
Significant intercepts from the drilling include:
7m @ 2.97 g/t from 80m (incl. 1m @ 13.4 g/t from 84m) WURC0567
4m @ 3.70 g/t from 118m (incl. 1m @ 6.55 g/t from 120m) WURC0569
2m @ 4.64 g/t from 88m (incl. 1m @ 8.34 g/t from 88m) WURC0570
4m @ 4.24 g/t from 94m (incl. 1m @ 13.3 g/t from 96m) WURC0575
2m @ 28.34 g/t from 75m (incl. 1m @ 47.0 g/t from 76m) WURC0577
8m @ 5.82 g/t from 87m (incl. 4m @ 10.2 g/t from 89m) WURC0579
12m @ 1.72 g/t from 59m (incl. 1m @ 6.96 g/t from 60m) WURC0580
6m @ 7.97 g/t from 106m (incl. 1m @ 37.1 g/t from 107m) WURC0583
One of the underground diamond holes GAGC0241 (1.0m @ 15.5 g/t Au) appears to have intercepted the Golden Age North structure at a depth of 370m below surface, a further 220m deeper than the surface drilling. The Golden Age North structure looks to cross the Golden Age Middle orebody and development drives, suggesting they are separate structures. Further drilling is required to confirm that this intercept is the Golden Age North structure and that it remains open at depth.
Significant intercepts from the latest program lie outside of the current Golden Age North pit optimisation and below the existing mined pit floor. With the depth to fresh rock approximately 50m, the ore zones are amenable to both open pit and underground mining. The deeper, northern-most intercepts are located approximately 150m from existing underground infrastructure allowing for lower-cost underground access.
Golden Age remnant mine plan growing
A diamond drilling grade control programme has been completed in conjunction with the resource extension drilling in the Golden Age Middle zone focussing on quartz lodes not identified or extracted by previous operators.
Two separate quartz lodes were intercepted in a number of holes validating the over-lapping nature of the reef. The best intercepts were:
2.1m @ 43.6g/t and 1.11m @ 7.28g/t 92 g*m GAGC0244
6.1m @ 8.88g/t and 2.8m @ 5.81g/t 74 g*m GAGC0243
5.1m @ 4.15g/t incl. 1m @ 12.0g/t 21 g*m GAGC0233
1.1m @ 17.4g/t and 0.7m @ 4.17g/t 19 g*m GAGC0238A
2.1m @ 7.87g/t 16 g*m GAGC0241
This drilling has extended the current mine plan of three lenses in the remnant part of the mine. This additional ore is expected to be mined over the next 4 months.
Following the successful drilling campaign, Blackham is re-estimating the open pit free milling resources and reserves around the Wiluna Mine site. Blackham's management team believes the free milling ores within the existing Wiluna Mine footprint are an attractive feed stock for the current operating mill and allows for fast tracking mining approvals.
Blackham has also commenced a 2,600m RC and Diamond drill programme for the Lake Way prospects targeting the southern extensions to the Williamson orebody and the 2.5 kilometres of strike on the Carroll-Prior structure. No exploration drilling has taken place in this area for over 12 years.
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About Blackham Resources Ltd
Blackham Resources Limited (ASX:BLK) (OTCMKTS:BKHRF) Wiluna-Matilda Gold Operation is located in Australia's largest gold belt which stretches from Norseman through Kalgoorlie to Wiluna. The Operation now includes resources of 96Mt @ 2.2g/t for 6.7Moz Au all within 20kms of the central processing facility. Blackham has consolidated the entire Wiluna Goldfield within a +1,100km2 tenement package which has historically produced in excess of 4.4 million ounces over a 120-year mining history.
Chantelle O Sullivan