1. The Deep Lead Mines of BALLARAT

2. What does this image represent to you?

3. And this?

4. Section 500 million years ago Under the sea

5. Map 500 million years ago Flat layers of sand and mud on the sea floor

6. Section 490 – 450 million years ago Squeezing and folding - mountain building

7. Section 450-350 million years ago

8. Section 350 – 65 million years ago Erosion

9. Map 65 million years ago - Hills of 500 million year old rocks Flat plain

10. - drained by rivers

11. Section 65 – 3 million years Lava flows Vulcanism

12. Map 3 million years ago – west covered by lava

13. Todays river system Where is the ancient river system?

14. WHERES THE GOLD In the youngest river system (Yarrowee River etc) In the quartz veins in the oldest rocks (Whitehorse Range, Black Hill) and buried under the lava flows of Ballarat West Widely spread in the old plains gravels (Golden Point, Poverty Point, Newington Gravels) Highly concentrated in the ancient river beds

15. LEAD Any mineral deposit formed by mechanical concentration in the bed of a stream by water action

16. SHALLOW LEAD Any lead that is:- Not buried by younger rocks (sediment or lava) The course of the lead can be determined by the present topography

17. DEEP LEAD Any lead that is:- Buried by younger rocks (sediment or lava) The course of the lead cannot be determined by the present topography NOTE. There is no qualification of depth

18. 30 metres 90 metres 40 metres 60 metres 110 metres 75 metres 95 metres Canadian Lead Inkerman Lead Golden Point Lead Eureka Lead Cosmopolitan Band and Albion No 2

19. Section across the Ballarat goldfield Golden Point Lead Canadian Lead Lava flows Sovereign Hill Yarrowee River

20. Consols Lode Drainage Direction

21. Ballarat Leads – Regional Context

22. The Deep Lead Mines of Ballarat

23. The Pleasant Street Group of Mines

24. Section through typical deep lead Drill hole GutterDrift Basalt Bedrock

25. Sketch Plan and Long Section of Typical Deep Lead Mine

26. Sketch Section across Lead Showing Mine Workings

27. Plan of Deep Lead Working Method

28. Timbering of Wash Dirt Drives Bedrock

29. Challenges to Deep Lead Mining Much water – extensive pumping necessary Basalts very hard – required blasting Deep sinking to reach lead Lead direction varied unpredictably Unstable ground in the wash dirt

30. More Challenges Very long drives – ventilation often poor Very long drives – haulage issues Mines needed to be highly mechanised Large Capital Investment required Poor legislative environment Resource is finite, unlike quartz vein mining

31. Deep Lead Mining Issues The Frontage Claim System

32. Advantages of Deep Lead Mining Gold concentration much higher per unit volume Wash Dirt required less processing than quartz ores to release the gold