21 June, 2014

Branching out - mining on Woodbourne Creek

Recently I had the chance to examine a little more of the goldmining history of the Bamganie/Woodbourne Creek region with a trip to see a mine not too dissimilar to that at Mt Doran which I wrote about previously. Mining in this area dates back to the 1870s, with gold discoveries first at Bamganie in 1874 and then along Woodbourne and Cargerie Creeks in the following year as I have discussed in a previous post. Over the following decades, well into the 20th century, miners came to try their hand at striking gold in the area, working both on the surface (the subject of a my next post) and below ground.
This mine was not only interesting for the tunnel which, like the other mine, ran back into a hillside, but also for the vestiges of the mining process which could be seen scattered around the site. The first object pointed out was a metal boiler lying partway up the slope.
Discarded boiler
Lower down the slope, below both the boiler and the mine, there was also evidence that the creek had been dammed to provide water for various mining processes, whilst up the slope was a brick structure which our guide pointed out was constructed from Hoffman bricks.
Brick structure above the mine entrance

Hoffman brick
The Hoffman Brickworks was a Brunswick-based company established in 1870, which used various innovative brickmaking techniques over the years before finally closing its doors in 2005. These artefacts suggest that the site must have shown some potential and been backed by investors.
The interior of this mine was in many ways similar to that I viewed at Mount Doran and described in this post. It had timber support structures and according to our guide, showed evidence of some engineering skill in its construction.

Tunnel near the entrance

Tunnel with timber supports
To my inexperienced eye however, the composition of the rocks and soil seemed somewhat different and the presence of fine tree roots dangling through from the roof in this mine was also a point of difference.
Tree roots hanging from the roof of the tunnel
Commonly, gold-bearing quartz is found in the presence of iron ore. This was certainly the case across the goldfields of the Moorabool and Leigh Rivers. At the foot of Bungal Dam, not far from the mine I investigated near Mt Doran, commercial quantities of iron were mined during the late 1870s and early 1880s.
Likewise, the land around Bamganie and Woodbourne Creek contains iron. Geological survey maps from the 1860s show areas between Cargerie and Woodbourne Creeks where the soil is composed of  "ferruginous conglomerate containing [an] abundance of rounded quartz pebbles" and "thick beds of ironstone cement & quartz gravel the later containing rounded quartz boulders...where these occur payable gold has been obtained". The maps also indicate that "gold has been found in many places along Reid's [Woodbourne] Creek and in some spots payable". Unlike the gold, the iron ore was presumably not deemed payable however it was clearly present as evidenced by the rusted colour of some of the quartz.
Quartz showing rust stains caused by the presence of iron

A quartz vein showing staining
In addition to the tell-tale rust stains which would alert miners to the presence of iron and the potential for gold, another indicator was the appearance of a black line running through the rock. Such a line can also indicate the presence of iron and therefore gold. I am told that this is a result of the oxidation which can occur where soils of different mineral types come in contact and my research suggests that the black colouration may be haematite, a type of iron oxide.
Black oxide running along the rock face
An example of this was clearly present here (as can be seen in a number of the above pictures) where the line would have dictated the direction of excavation.
At the mouth of another nearby shaft, marks in the rock left by the miners' picks can still be seen as they explored what may have been another promising lead.

Pick marks still visible on the rock surface
A little further away still, the signs of surface prospecting are clearly evident also, but that will be discussed in my next post.

1 comment:

  1. Dear Jo what a great post. I am really interested in mining history and have been going a bit of googling on Woodbourne (Reids) Creek having picked up the reference on the 1868 Geological Survey Map No 64 that refers to the payable gold along Reids Creek. Would you be kind enough to let me know the location of the mine you have described - Cheers Kevan - from Ballarat