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The Hill that made BHP AusIMM Nov11 v2
The document discusses the history of the Broken Hill deposit in New South Wales, Australia and the development of the Broken Hill Proprietary Company (BHP). It describes how the deposit was discovered in 1883, with mining and infrastructure rapidly developing. BHP became a major mining and smelting operation. The geology of the deposit, consisting of multiple stratiform ore lenses, controlled the orientation of mining leases and urban development in Broken Hill city. Over its lifetime, the deposit produced over 19 million tonnes of lead, 16.6 million tonnes of zinc, and 28.7 million kilograms of silver.
The Hill that made BHP AusIMM Nov11 v2
- 1. The hill thatmade BHP The ‘broken hill’ in NSW Tony Webster FAusIMM(CP)
- 2. Introduction This presentation isNOT about the geology of the Broken Hill region, or the structural history and genesis of the orebodies If people are interested, I can present that in another talk. I have tried to focus on aspects of the geology of the ‘broken hill’, that influenced the history and development of the Broken Hill Proprietary Company Ltd, and the ‘Silver City’ that developed next to its mine The Palaeoproterozoic Willyama Supergroup in Far Western NSW
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- 4. Top 30 StratiformSedimentary Zn-Pb Deposits Assoc Prof Steve Walters, CODES
- 5. The 1885 prospectusprinted in Silverton – 25km from BH From Bridges, 1920 The Prospectus
- 6. Charles Rasp, BoundaryRider (right) Originally from Germany, – climbed the hill near the boundary of Mt Gipps and Kinchega ‘Run’s and collected samples on the 5th of September 1883 – later assay revealed traces of silver. Rasp is buried in the North Rd Cemetery in Adelaide. His mansion ‘Willyama’ is in the suburb nearby. The story of his widow Agnes, and how she spent his fortune is a whole other story. George McCulloch, Station Manager (left) McCulloch married the widow of one of the men from Mt Gipps Station He became a well known patron of the arts in London (the best collection of modern British Art in the world) He died in London. The Men that Made BHP From Bridges, 1920 Both men died in 1907.
- 7. Guillaume Delprat, Engineer(left) Dutch-born GM of BHP from 1899-1921 – moved the company from silver to iron and steel making and laid the foundations for BHP’s future success. Developed one of the earliest floatation processes (the Potter- Delprat process). In 1935 Delprat was the first recipient of the medal of the Australasian Institute of Mining and Metallurgy William Jamieson, Surveyor (right) Was in Silverton surveying mining leases and bought in to the syndicate (3 shares – later sold two) – became the first Manager of the Broken Hill Mine. A director on the Melbourne board in 1906-26. Harry Campbell, William Jamieson’s Aboriginal horse minder discovered the richest near-surface silver ore ever found at Broken Hill in 1885, while prospecting the southern end of Block 12 with his sledgehammer. This ore paid all of the capital costs of the mine development (e.g. Bridges, 1920). Wikipedia, . The Men that Made BHP From Bridges, 1920 Delprat’s daughter Paquita married Douglas Mawson
- 8. The ‘broken hill’ Outcrop,Geology, Topography and Oxidised Zone.
- 9. The Outcrop Views ofthe ‘broken hill’ in 1884 Taken from the southwestern end (NW side) and looking northeast Sources: Upper photo: Broken Hill Outback Archive (courtesy of Brian Tonkin) Lower photo from Bridges (1920)
- 10. Mrs W. R.Wilson and family on the outcrop, looking northeast over Block 14, 1885. Note the dog at left. From Fischer (1970) The Outcrop ‘Mine managers family’ (probably Mrs W. R. Wilson and family) on the highest part of the lode outcrop, looking southwest over the BHP, 1885. Note the dog (again). From Kearns, 1996. Views of the ‘broken hill’ in 1885 So much for the rugged, male-dominated culture of early Broken Hill!
- 11. Single Quarters –c1890’s View of the ‘broken hill’ from the south- eastern side - date unknown but probably early 1890’s The Outcrop Broken Hill Outback Archive (courtesy of Brian Tonkin)
- 12. Single Quarters –c1890’s View of the ‘broken hill’ from the south- eastern side - date unknown but probably early 1890’s The Outcrop Broken Hill Outback Archive (courtesy of Brian Tonkin)
- 13. The Outcrop: Topographyreflects the underlying geology Topography, lode outcrop and open cut positions From Webster, 2004; 2006 & unpublished
- 14. BHP Mine 1,2 and 3 Level Orebody Geology After Webster (2004; 2006) Prominent features of the outcrop reflect structures in the orebodies The Outcrop: Topography reflects the underlying geology
- 15. The Topography ofthe Hill Contour Plan of Broken Hill c1885 – with original leases. Sketch of the Broken Hill settlement (now Delamore St) in 1885 by Surveyor, W R Thomas (from Kearns, 1996) Track will become Argent St Pre-mining topographic contour map of the ‘broken hill’ Constructed from early surveys (mainly Andrews, 1922 and Gustafson, 1939) Contours are at approx 3.3m intervals (10 feet) Rocky bluffs = --------- From Webster, unpublished
- 16. The Topography ofthe Hill Contour Plan of Broken Hill c1885 – with original leases. Sketch of the Broken Hill settlement (now Delamore St) in 1885 by Surveyor, W R Thomas (from Kearns, 1996) Track will become Argent St Rocky bluffs = --------- From Webster, unpublished
- 17. In 1885, itwasn’t at all certain if the hill would come to anything. A newly graduated 19yo chemist and assayer, W. H (‘Bill’) Corbould, would often stroll up the hill with a friend ….. ‘If ever it turns out any good, we can say we sprayed it in its infancy’ In the 1920’s, Corbould consolidated the Mt Isa field and founded Mt Isa Mines (MIM) Photo & story from Hore-Lacy, 1981 The Topography of the Hill and occasionally they’d piss on it.
- 18. Images: Left, AustralianMuseum; right, Chapman Collection The early wealth of BHP was the result of the rich supergene (oxidised) zone below the surface of the hill – particularly on the BHP Mine 1 and 2 Levels. Modified after BHP (unpublished); Jamieson and Howell, (1893), and Webster (2004; 2006) Geology - Supergene-enriched Oxidised Zone
- 19. Images: Left, AustralianMuseum; right, Chapman Collection The early wealth of BHP was the result of the rich supergene (oxidised) zone below the surface of the hill – particularly on the BHP Mine 1 and 2 Levels. Plan of 212 foot level Silicious Iron Ore Kaolin & Iron Silicious Carbonate of Lead Silicious Iron & Kaolin Carbonates Oxidised Ore Oxidised Ore Kaolin Kaolin Silicious Ores Carbonates Silicious Ore Carbonates Modified after BHP (unpublished); Jamieson and Howell, (1893), and Webster (2004; 2006) Geology - Supergene-enriched Oxidised Zone
- 20. The Geology ofthe ‘hill’ From Webster, 2004; 2006
- 21. The ‘broken hill’ SurfaceInfrastructure
- 22. ML 12 ML13ML 11 Surface Infrastructure of the Broken Hill Proprietary Mine 1892 Mining and treatment infrastructure – on the flanks of the hill Development of the mining infrastructure was very rapid once the field was proven Photo sources: BHP and Kearns (1996)
- 23. ML 12 ML13ML 11 Surface Infrastructure of the Broken Hill Proprietary Mine 1892 Mining and treatment infrastructure – on the flanks of the hill Development of the mining infrastructure was very rapid once the field was proven And it wasn’t just mining infrastructure….. Photo sources: BHP and Kearns (1996)
- 24. • Geotechnical issues(wide stopes with poor underground support) led to the removal of mining infrastructure from the flanks of the hill and the • Adoption of the square set timber system of stope support in 1888 (from the Comstock Lode in Nevada - North Forest Products originally formed to supply mine timber) The ‘Creeps’ – Geotechnical issues lead to a rethink Square set stoping was still in use at North Mine until just before the North Mine closed in 1993. Hydraulic fill was later perfected at the South Mine Central Mine mill wrecked by ‘creep’ in 1905. From Blainey (1968)
- 25. The Smelters BHP Smeltersin in 1894. Source: Alban Lynch, talk to AusIMM Melbourne Branch, Feb 2008 Originally four smelters in BH • Block 14, • British, • Central and • BHP - BHP’s the biggest in Australia BHP had a small silver refinery in Port Pirie and had bought the small British Broken Hill smelters there in 1892
- 26. The Smelters Early 1890’s:decision made to move smelters to the coast (depletion of oxidised ores, floatation, cheaper fuel, transport etc). All had closed by April 1898. BHP smelter, Port Pirie, South Australia, 1906 From Blainey (1968) The Port Pirie smelters needed ironstone flux. The nearest source was directly across Spencer Gulf, at an ironstone hill called the ‘iron knob’. BHP acquired the lease.
- 27. The City ofBroken Hill
- 28. Caldwell’s impression ofBroken Hill (later Delamore St) in late 1884. From Worner & Mitchell (1983) 1885 sketch of Broken Hill by J. Renowden (from Kearns, 1996). Images of Delamore St, Broken Hill – from Google Maps Development of the City of Broken Hill
- 29. Eastern end ArgentSt and Delamore St, 1886 (from Solomon, 1988) Caldwell’s impression of Broken Hill (later Delamore St) in late 1884. From Worner & Mitchell (1983) 1885 sketch of Broken Hill by J. Renowden (from Kearns, 1996). Images of Delamore St, Broken Hill – from Google Maps Development of the City of Broken Hill
- 30. While the mininginfrastructure developed on the flanks of the hill, the town grew on the alluvial flats to the north. Development of the City of Broken Hill
- 31. Development of theCity of Broken Hill: The geology controlled the ML orientation – which influenced urban layout Google Earth image of the central part of Broken Hill
- 32. Development of theDeposit 1890’s – 1930’s
- 33. Longitudinal section ofthe Broken Hill mineralised system (2004) The Topography Reflects the Underlying Geology Lost to erosion Only about 3 million tonnes of mostly low- grade mineralised rock lost to erosion Modified from Webster, 2004; 2006
- 34. Metal Production 1883-1994 (PasmincoLtd, unpublished data, 1995) • 19.3 mt Pb, • 16.6 mt Zn, • 28.7 million kg Ag, • 23 t Au (a bi-product of base metal mining). The Potosi & Silver Peak orebodies are probably the continuation of the main lode system By the late 1930’s it had been recognised that the deposit consisted of multiple ore lenses. Eventually there were at least nine spatially associated, flattened & ribbon-like stratiform orebodies defined. The Deposit – Multiple Ore Lenses BHP Mine Steep north and south plunge not fully recognised in the early days. • Others pegged the leases to the south and far north of the BHP ground • To facilitate the rapid development of the field and possibly to share some of the risk, BHP floated off separate companies based on their northern leases (these mines ultimately passed to other owners)
- 35. 2 km 3 Lens 3Lens & 2 Lens extend for most of the length of the field, a distance of over 8.5 km & until recently accounted for most of the production from the field. The Deposit – Multiple Ore Lenses BHP Mine Subsequent deeper mine development was to prove that most of the tonnage of high grade ore was in the down-plunge extensions to the south and north Modified from Webster, 2004; 2006
- 36. 2 km 2 Lens 3Lens & 2 Lens extend for most of the length of the field, a distance of over 8.5 km & until recently accounted for most of the production from the field. The Deposit – Multiple Ore Lenses BHP Mine Modified from Webster, 2004; 2006
- 37. 2 km A LodeLower/Upper/Southern, Western AL/Western Min, 1 Lens Several lesser-mineralised horizons predominate in the SW & now account for most of the production of the field. • A Lode Upper (ALU), • A Lode Lower (ALL), • 1 Lens Upper (1LU), • 1 Lens Lower (1LL) immediately above 2L. Southern A Lode lies in the same stratigraphic position relative to BL as ALU but is a distinct occurrence to the southwest, and Southern 1 Lens is a separate ore horizon occupying the 1L stratigraphic position in the southwestern Perilya Mine. Probably more closely akin to B Lode, The Deposit – Multiple Ore Lenses BHP Mine Modified from Webster, 2004; 2006
- 38. 2 km B Lode(lies at the top of the succession of lesser mineralised horizons). Several lesser-mineralised horizons predominate in the SW & now account for most of the production of the field. The Deposit – Multiple Ore Lenses BHP Mine Modified from Webster, 2004; 2006
- 39. 2 km ‘C Lode’& 4.5 Mineralisation The 4.5 Mineralisation lies outside the Hores Gneiss. C Lode Mineralisation is mostly derived from B Lode The Deposit – Multiple Ore Lenses BHP Mine Modified from Webster, 2004; 2006
- 40. Longitudinal section ofthe Broken Hill mineralised system – looking northwest Why did BHP leave Broken Hill? BHP finally closed its mine in 1939 after spending several years scavenging ore during periods of favourable metal prices. It withdrew from Broken Hill in 1940. Broken Hill South Ltd later acquired the leases and extracted a large volume of remnant ore (largely as a result of the perfection of the hydraulic fill process). In 2011, the new Rasp Mine (CBH Resources) is developing a low grade orebody in the former BHP lease area By 1909 the BHP mine was hemmed in, with depleting ore stocks. Delprat recognised that the mine was dying
- 41. Longitudinal section ofthe Broken Hill mineralised system – looking northwest Why did BHP leave Broken Hill? BHP finally closed its mine in 1939 after spending several years scavenging ore during periods of favourable metal prices. It withdrew from Broken Hill in 1940. Broken Hill South Ltd later acquired the leases and extracted a large volume of remnant ore (largely as a result of the perfection of the hydraulic fill process). In 2011, the new Rasp Mine (CBH Resources) is developing a low grade orebody in the former BHP lease area By 1909 the BHP mine was hemmed in, with depleting ore stocks. Delprat recognised that the mine was dying
- 42. Legacy of the‘Big Mine’ in Broken Hill
- 43. Remnants of BHP’sPresence in Broken Hill Chimney of the first camp (Jamieson's) The leases of the Broken Hill Field (now consolidated mining leases) From Bridges (1920)
- 44. ‘Proprietary Square’ –the BHP senior staff housing area. Delprats house still stands (with the Billiard Room he added after becoming hooked on the game) – now the Perilya Social Club Remnants of BHP’s Presence in Broken Hill Image of Proprietary Square, Broken Hill – from Google Earth
- 45. Remnants of BHP’sPresence in Broken Hill The black slag dump that dominates the skyline The foundations of the ‘New’ Mill Delprat’s Shaft (with later headframe) The office site is now under the rail yards at the bottom end of Sulphide St – built during the war to tranship freight from the standard gauge to the narrow gauge Silverton Tramway to SA A lingering legacy is the deep-seated hatred of the company by the locals – BHP won most of its battles with the unions Images surviving features if the BHP Co Ltd’s infrastructure at Broken Hill – from Google Maps
- 46. What is leftof the ‘hill’? - Browne Shaft Webster (2004; 2006)
- 47. Browne Shaft lookoutcutting Shows Mn carapace over 3 Lens What is left of the ‘hill’? - Browne Shaft Webster (2004; 2006)
- 48. These principles ofmining infrastructure placement still apply today. Only the scale has increased If you think that this is all irrelevant history and that it doesn’t apply to the modern world, think again Is this stuff relevant?
- 49. These principles ofmining infrastructure placement still apply today. Only the scale has increased Is this early view of the Hub and Mt Whaleback from Newman all that different to Broken Hill in the 1890’s? Source Eckhart (1998) If you think that this is all irrelevant history and that it doesn’t apply to the modern world, think again Is this stuff relevant?
- 50. There is anotherhill that features very prominently in the history of BHP – Iron Knob in South Australia But that story is for another day. Last Word