We would all like to see replicated at Allendale the normal mining history of other goldfields in Victoria.
The well-known fact is that at places such as Ballarat, Clunes and Daylesford, the mining of gold in the gravels on any ancient surface was followed -- sooner or later -- by the deeper working of lodes. These lodes formed ore zones - proven very narrow ( typically less than 50 metres wide), but also very lengthy.
We understand that the disintegration of parent rocks above some line of lode is / has been the source of gold found in gravels. It can be accepted that the erosion of the rocks once above the Consols line dumped clays, gravels, and gold into the famous Golden Point Lead. Mine manager A.J.Forbes made short work of stripping out those gravels, creating work places so as to pull up nearly 10,000 trucks per week (along with all gold in those gravels).
Here is a sketch of the controlling work place. This, from Dickers Mining Record, 28 November 1867, shows the plat ( "platform") at the base of shaft. The space is 40 feet long by 12 feet wide, the floor protected by strong sheets of iron. Trains of trucks numbering 12 to 15 per train, turn about here, Trucks one above the other - two at a time - are hoisted to surface at rates of up to 640 per 8 hour shift.
For those people interested in quantities, tests run in June 1860 showed that 3 similar trucks of "loose" gravel and ground from this Redan lead held 23 cubic feet of solid "stuff".
Maps record the location of this shaft - the Golden Gate or No.2 - and history tells of its gold. Forbes knew more than others, so -
- sunk the shaft to 230 feet by 30 April, 1863, and kept on sinking,
- finished the shaft at 450 feet, then opened up the chamber shown in the sketch 7 September, 1863, at depth 420 feet,
- struck the wash-dirt May 1864.
There were once huge piles of waste from treatment of wash-dirt, just as near Allendale today. Those at Ballarat were removed in the 1950s, to build the White Swan reservoir embankments. Few residues remain around Ballarat today.
This Golden Gate shaft location is about 250 metres west of what became known as the Consols No,1 lode - not found until 1879.
Zones with veining frequently are found to occur on some topographical high, or ridge. A similar ridge ( buried by basalt ) carries the workings all along the Consols line of lode - a distance of 3,000 metres.
In year 1995 a deep shaft collar was sunk on this same Consols Line of lode. As a result, photos exist to record the nature of the upper ground, surface to 18 metres.
The 1995 shaft sink penetrated beyond the over-lying basalt. At its base, the basalt was found to be severely decomposed. The basalt flow had draped itself over the ridge, covering a thin sandy horizon on that ancient surface. All these features may be seen in the composite photo below
In the far right of the composite photo, the pale blue is the colour of the ancient rocks, oxidized and weak. Further sinking reveals flat veins within the oxidised rock, as this second photo attests.
The photos above are from Ballarat West, not property of Mount Rommel Mining Ltd.. The photos are helpful in illustrating how seemingly insignificant rocks can exist 50 metres vertically above one of the richest ore zones ever found in Victoria's goldfields. The photos came about because a shaft collar reconstruction was taking place there in year 1995. In that location geophysics - the CSAMT method - could not be applied, and sites for drilling were limited indeed.
At Allendale, the geophysical results appear to be exceptional. A lengthy narrow zone of unusually conductive rocks outlined by the geophysics is located near to a buried topographic high. We have chosen to test this lengthy zone first at its northern end. The test depths will be metre by metre, down to 130 metres - that's the plan.
The "anomaly" position intended to be probed at Allendale can be anticipated to present similar characteristics. Thin basalt, weak upper ground, and casing needed to support the upper 70 metres of hole.
Lower down, in firmer ground, we should begin to find out why there is such an intensely conductive horizon.
Previous Chairman's Outlooks
10 April 2013
22 January 2013
22 December 2012
05 December 2012