The hill that made BHP was the Broken Hill in New South Wales, Australia. It contained a rich deposit of silver, lead and zinc that was discovered in 1883. This discovery led to the founding of the Broken Hill Proprietary Company (BHP) which became one of Australia's largest companies. The geology of the hill influenced the layout and development of both the mine and the city of Broken Hill. The deposit consisted of multiple ore lenses that extended over 8 km. BHP dominated mining at Broken Hill for decades but eventually withdrew in 1940 as the ore bodies became depleted. The mining legacy of BHP is still visible today through remnants of infrastructure and the slag heaps that dominate the landscape.

1. The hill that made BHP
The ‘broken hill’ in NSW
Tony Webster FAusIMM(CP)

2. Introduction
This presentation is NOT 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

3. Location,
Willyama Supergroup
Location

4. Top 30 Stratiform Sedimentary Zn-Pb Deposits
Assoc Prof Steve Walters, CODES

5. The 1885 prospectus printed in Silverton – 25km from BH
From Bridges, 1920
The Prospectus

6. Charles Rasp, Boundary Rider (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 of the ‘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: Topography reflects 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 of the 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 of the 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, it wasn’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, Australian Museum; 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, Australian Museum; 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 of the ‘hill’
From Webster, 2004; 2006

21. The ‘broken hill’
Surface Infrastructure

22. ML 12 ML 13ML 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 ML 13ML 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 Smelters in 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 of Broken Hill

28. 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

29. Eastern end Argent St 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 mining infrastructure 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 the City 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 the Deposit
1890’s – 1930’s

33. Longitudinal section of the 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
(Pasminco Ltd, 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
3 Lens & 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
3 Lens & 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 Lode Lower/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 of the 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 of the 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’s Presence 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’s Presence 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 left of the ‘hill’? - Browne Shaft
Webster (2004; 2006)

47. Browne Shaft lookout cutting
Shows Mn carapace over 3 Lens
What is left of the ‘hill’? - Browne Shaft
Webster (2004; 2006)

48. These principles of mining 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 of mining 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 another hill that features very prominently in the history of BHP –
Iron Knob in South Australia
But that story is for another day.
Last Word