If you use the forum search function you will be able to find everything you need to know about modern and past mining. Buying a few books about it all helps a lot too. I'm guessing mostly the 70s consisted of diesel machinery, hard rock mining w/ explosives and dredging technologies.
They would be trying to hit a gold reef or deposit with shafts or adits ( tunnels ) using hydraulic jackhammers to "drive" deeper and 8ft long drill bits for explosive charges to release the rock and break it to size managable enough for the miners to load into buckets for hauling up "winzes" via winch to an ore chute or straight to the ore cart. From here its pushed out on greases tracks to either a truck or straight into the processing plant which for a small scale company would consist mostly of several crushing and screening machines to pulverize the ore into a slurry to be then run down a "sluice", a tray with a series of catches or "riffles" and carpets, to catch the gold. sometimes mercury was spread onto copper plates back then to soak up fine gold particles that were too small for the riffles to catch and the mercury amalgam ( cannot soak up any more gold ) is processed through high temperatures to leave behind "sponge gold" which is then smelted to a button.
Being in Karlgoolie they would be struggling to keep the machines running with whatever struggling water resource they could find in the dry heat. If they wouldn't have water, they would resort to dry mining with machinery which doesn't use water but still similar mattings and riffles in a sluice but instead of water, gusts of air from a blower would push light material out as the heavy gold stayed.
Many arguments broke out with mines as struggling small scale mining teams search for gold in thier tunnels on limited funds. Some ended up hitting small loads, others fall into dispute ending in the mine being blown up by dynamite over jealosy issues too.
If you were to write a book on the subject, I'd suggest you get down n dirty and join in and experience prospecting first hand and see the gold sparkle with your own eyes and discover the amount of effort it takes to find it. At the same time, you have just as much of a chance as any of us finding a huge nugget on a goldfield. You never know.
Hope this info has scratched the surface for you.
