Greater Bendigo Gold Mines Ltd (GBM) | ACN 119 956 624

 

Diamond Hill Project

Diamond Hill Mining Pty Limited, a wholly owned subsidiary of the Company, is the holder of MIN 4622 and will upon registration of the transfers from Dougless Cahill become the owner of MIN 4872. The licences are located approximately 8 kilometres south of the city of Bendigo.

Local Geology

The licences are in the southern portion of the Bendigo Goldfield and are underlain by a tightly folded sequence of marine sediments consisting of repetitions of sands silts and mudstones which have been altered to lower greenschist facies. The licences cover areas of known workings, major folds, and faults and mineralised quartz reefs which trend approximately north to south. The Bendigo Goldfield is recorded as having produced approximately 17,000,000 oz of gold to an average depth of approximately 800 metres below surface. This production was obtained from a series of quartz reefs, which were associated with the anticlinal folds of the district. These reefs were extensive in the horizontal plane (up to 1.5 kilometres) and repeated regularly at depth. Johansen (1998) summarised the structural regime at Bendigo as follows:

Characteristics of auriferous quartz reefs at Bendigo:

• Reefs occur in close proximity to the anticline axis.
• Reefs have one long dimension which is sub parallel to the anticline crest (i.e. sub horizontal).
• Reefs occur as groups or ‘clusters’ in cross section suggesting an interrelated structural control.
• Reef clusters also have one long dimension which is sub horizontal. Reef clusters form sub horizontal ‘ribbons’ when viewed in three dimensions.
• Ribbons repeat at regular intervals with depth.
• The gold content of individual ribbons is independent of depth.

On the basis of this information BML has explored and identified numerous repeats within its licences, below old workings on the Bendigo Goldfield and Greater Bendigo Gold will explore its licences accordingly.

Mining Licence 4872

The deformed Palaeozoic bedrock of ML 4872 is mapped as
Early Ordovician (Bendigonian Zone 3). This is characterised by sand rich sequences and dominated by thick sandstone beds
(<2 metres) including coarse channel sands. The Christmas Anticline and the Opossum Fault to the west are the two main geological structures running north to south of the project area.

West dipping faulting has ruptured the hinge zone of the Christmas Anticline and controls mineralisation. The axis has been intruded by a kaolinised Devonian acid dyke. This intrusive rock is inferred to be equivalent in age to the Harcourt Batholith, which truncates the Palaeozoic rocks to the south.

Numerous quartz veins and known gold workings occur between the steeply west dipping Opossum Fault and the eastern limb of Christmas Anticline. This title covers approximately 300 metres of strike. The Salacia Shaft to the south and the main London Christmas Shaft as well as the Prospecting (Melbourne Hope) Shaft to the north are the three main shafts within the project area. The main London Christmas Shaft is the deepest in the licence area at 75 metres.

Historical Production

Alluvial gold was found in both German and Ramrod Gullies surrounding the Mining Licence. Early prospecting for the source of alluvial gold led to the discovery of auriferous quartz on the eastern flanks of the Christmas Anticline. Shallow open cuts mined these quartz reefs with varying success.

From the 1870s, several shafts were sunk along the line of quartz reefs and returns of up to 3 oz per ton were recorded. Shafts were shallow (45 metres maximum) and these were concentrated on the west dipping, fault hosted quartz veining in the eastern flanks of the anticline. Approximately 10,000 oz were produced for this period.

The bulk of the historic mining in the early 1900s by the London Christmas Company concentrated on quartz bodies associated with the strong west dipping fault zone. Water proved to be a major problem at that time and prevented sinking past 75 metres. The intersection of these faults with the anticlinal axis at depth was never reached due to economic and technical issues.

The London Christmas Company treated approximately 2000 tons for an average grade of 7 g/t Au. Mining ceased in the 1920s as this grade was uneconomic at that time.

The Melbourne Hope Company sank a shallow shaft to the north of the main shaft in the late 1920s. The company worked a spur body at 30 metres depth before it ceased mining. About 150 tonnes were treated for 50 oz at approximately 10 g/t gold recovered.

Previous Exploration

The London Christmas shaft was reopened in the 1980s and minor exploration work was carried out before the shaft was recapped.

Exploration work carried out by Greater Bendigo Gold includes the compilation of historical research data, structural interpretation and on-going field mapping.

Two exploratory drill holes were drilled opposite the main shaft to test for open cut potential on the eastern side of the fold (up dip along faulting). Stoping was intersected close to surface and the programme was abandoned. Hole H2 showed minor quartz veining from 18 to 28 metres down hole. The results of the drilling program were disappointing. In addition, drilling sub parallel to the fault plane returned little useful information.

Structural interpretation of the level plans shows that the quartz hosting the mineralisation is controlled by the intersection of various fault planes.

While the plunge of the fault planes is south, the mineralisation shows a distinct northern plunge which appears to be as a result of the intersection of various secondary fault plane structures within the main hanging wall and foot wall. The exact nature of these relationships needs to be determined.

Proposed Exploration

The geometry and distribution of auriferous quartz bodies as well as varying plunges of these ore bodies in the complex anastomosing fault structures at London Christmas are not yet fully understood. The Company intends to carry out detailed field mapping in order to understand the relationship between repetitive ore shoots and oblique structures as well as understand the movements along these fault planes. The aim is to target the geological continuation of fault bounded auriferous zones and possible deeper fold axial hosted targets.

The Company has two distinct targets in ML 4872.

1. The main target is the down fault-plane potential beneath the existing workings

• The mining history in Bendigo suggests that the best grades of gold were obtained close to the fault and fold axis junction.
• The existing development is still some 40 metres up dip from this junction and the Company believes a reasonable target still exists between 75 vertical meters and 110 vertical metres below the main shaft collar.
• A diamond drilling programme will target this area on a minimum of three sections with wedges to outline the quartz development and structural regime.
• Additionally the London Christmas will be uncapped, an exploration head frame erected and the shaft made safe in preparation for underground mapping and possible bulk sampling. Should diamond drilling be successful in delineating further resources, a feasibility study on gaining access to these areas by either decline or sinking the London Christmas shaft will be undertaken.

2.  Repetitions of the known structural regime at depth.

• Based on work completed by Bendigo Mining Limited (BML) the structural regime observed from surface to 75 metres at London Christmas can be interpreted to repeat regularly with depth. With the deepest workings on the Bendigo goldfield below 1400 metres, the extent of this structural regime is well demonstrated.
• Greater Bendigo Gold will undertake deep diamond drilling to assess the frequency and size of repeats at depth. A parent hole will be put in and regular wedges run of to gain comprehensive information on the structure at depth on the Christmas anticline

Mining Licence 4622

This title covers approximately 1 kilometre of strike along the Carshalton Anticline and the Carshalton Fault with the Stafford Fault to the east. Both alluvial and hard rock gold was mined from this property from the 1850s. Numerous old gold workings occur between the eastern limb of Carshalton Anticline and Stafford Fault. The open cut workings of the Golden Fleece Extended are within the lease as well as the Day Shaft and Halliday’s Shaft.

Historical Production

In the mid 1930s, the Golden Fleece Extended company worked a wide mass of spurs at approximately 25 metres depth and crushed approximately 2,500 tonnes at an average grade of 6 g/t Au. The mine closed due to economic conditions of the day.

Previous Exploration

A small syndicate opened the Day Shaft in the mid 1980s and undertook minor sampling without any encouragement. In 1998, three RC drill holes were drilled at the Day Shaft. These drill holes were oriented to the east (across strike) and angled at 55 degrees. The samples were assayed by 3 Kg BLEG and encouraging anomalous intersections were obtained from all drill holes.
The best intersection from drill hole Y5 was 5 metres @ 1.3 g/t Au from 32 metres including 1 metre @ 5 g/t Au from 35 metres.
This intersection corresponded with significant quartz percentages and increased mineralisation and was only a short distance below the Day Shaft. A further round of RAB drilling was undertaken with no significant intersections.

Proposed Exploration

The main priority at MIN 4622 is to test for low grade large tonnage spur bodies close to surface. Research and the limited drilling completed to date, has outlined spurry quartz bodies as the most likely target to host significant resources within MIN 4622. These spur bodies appear to be fault controlled and a programme of field mapping to identify the main structures in the area will be followed up by 3D computer modelling and close spaced drilling.

The exploration program will consist of:

• The completion of historical research to ensure that the model for drilling is correct and to check for additional mineralisation styles.
• A comprehensive field mapping programme.
• RC drilling to 100 metres depth to assess shallow targets.
• Deeper and directed diamond drilling to confirm structural interpretation and repeating frequencies.
• Reopening the Day Shaft and sink a further 20 metres to enable bulk sampling to be undertaken to assess grades.

Conclusion

Both titles at Diamond Hill provide exposure to the Bendigo Goldfield in areas of relatively low levels of previous development. Of significance are the shallow depths of the development which exists at Diamond Hill.