#gold #goldprospecting #mining
Today I'm going to take you out to the Maryborough Goldfields and show you a heap of interesting examples of alluvial gold mining, the features of which can vary a quite lot depending on the depth of the field.
We're going to take a look at surfacing, gully workings, shallow underground workings, shallow sinking, and deep lead mining, which are all types of alluvial workings at different depths.
Alluvial gold deposits are formed when gold is eroded from its source in a quartz reef, and then transported by water and gravity to a new location. The gold makes its way downhill over time until it is eventually deposited into a river, stream or gully.
One of the most important things to keep in mind when thinking about gold, is that it's heavy - real heavy, and over time it makes its way deeper and deeper down in the ground, or in a riverbed, until it can't go any further - usually when it hits bedrock. The old miners in the gold rush called this the bottom.
The gold sits in a layer on top of the bedrock, a layer which the old timers referred to as washdirt, washing stuff, or simply stuff. This rich layer could be anywhere from less than an inch to a few feet thick. Unless you were over in the incredible Gravel Pits at Ballarat, where the washing stuff was reported to be an astonishing thirteen feet thick!
The depth of alluvial workings generally depends on one important factor - how deep that bedrock lies beneath the ground.
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Mining models - Carl Nordstrom, 1850s. Museums Victoria
Historical images - State Library Victoria
Deep Lead Diagram - Gold Fields and Mineral Districts of Victoria, R. Brough Smyth, 1869
Drawings of deep lead mines - Andrew Swift and Robert Kaufman