Castle Hill Blackstone Reserve, Blackstone, Queensland

  • By Ken Grubb, Principal Moreton Geotechnical Services Pty Ltd and Greg Maiden, AusIMM Mining Heritage Committee

Bypassed by the nearby Cunningham Highway and 5 km removed from the central business district of Ipswich, the suburb of Blackstone in Queensland today reveals little of its past industrial significance for the Queensland coal mining industry.

But the topographic landmark of the suburb, now known as Castle Hill, hides evidence of an industrial and social heritage that is being showcased through the development of a new multi-use heritage park – the Castle Hill Blackstone Reserve (Figure 1).

Figure 1. Location of Castle Hill Reserve, Blackstone Qld (Grubb 2014, page 3).

An initiative of the Ipswich City Council, in collaboration with local heritage groups, the Castle Hill Reserve is an archaeological site described as ‘a walking museum’.  Its trails lead visitors through a landscape that reminds one of the sense of industry that existed here in the heyday of the Bundamba Coalfield and demonstrates the environmental legacy of the shallow underground mining methods of that era.

The name of the site is drawn from the grand mansion of Brynhyfryd (pronounced Brin-Huv-Rid), which once stood on the site. This was the original ‘castle’, and home of Welsh mining entrepreneur and philanthropist Lewis Thomas, whose heritage is also celebrated by the reserve.

Castle Hill overlooks the former mining village of Blackstone and lies at the heart of the historic Bundamba Coalfield that stretches northward to the Bremer River. The Castle Hill Reserve area comprises 40 hectares of bushland lying immediately to the south of the intersection of Thomas and Mary Streets, Blackstone and is located on land that rises from 20 m AHD along Bundamba Creek in the north, rising to the south to peak at 105 m AHD at Castle Hill itself (Figure 2). Abandoned since 1930, the area is now lightly forested woodland and the summit commands a view of Moreton Bay and the city of Ipswich through to the Daguilar Range to the north.

A major geographic feature of Castle Hill is a deep incision known as Blackleg Gully. The presence of this gully promoted the development of the first underground mining on the hill, but ironically also contributed to both the destruction of its greatest icon and to the hill’s preservation from modern commercial real estate development.

Figure 2. Castle Hill Blackstone Reserve Topography (Grubb 2014 Figure 2).

Geology and mining history

The underlying geology of Blackstone is comprised of the Triassic Blackstone Formation, part of the Ipswich Coal Measures. It consists of up to 240 metres of folded and faulted conglomerate, sandstone and shale containing seven major banded coal seams (Figure 3). Lying on the western limb of the Bundamba Anticline, the stratigraphy of the coal measures under Blackstone dips approximately 15 degrees to the southwest. The resistant Aberdare Conglomerate forms the capping at the summit of Castle Hill.

Figure 3. Idealised Geological Section SW to NE through Castle Hill Blackstone (Grubb 2014 Figure 3).

The shallowest mined coal seam is the Aberdare Seam, with a total thickness exceeding 4 metres. This was first discovered in Blackstone, and was for many years the principal seam of importance for both the mines in the Blackstone area and for the economy of the state of Queensland. The seam was mined over most of the Bundamba coalfield and supplied up to 50 per cent of the state’s coal and royalties up to the early 1960s. The underlying Four Foot and Rob Roy Seams were also mined under Blackstone at various times from the 1890s and intermittently through to the 1980s.

Although most of the coals from the Bundamba coalfield were of excellent quality for steam generation, the friability of the coal created problems with degradation during handling. This was a problem for the grate-fed boilers of that time and a major constraint on the transport and preparation of the coal for the traditional markets of rail, shipping and industrial steam raising, as well as for export cargos. However, of particular significance to Castle Hill was that the coal also had a propensity for spontaneous combustion which, combined with the friability of the coal, meant that mining of the Aberdare Seam required careful ventilation practices and the need for substantial mining pillars to prevent roof collapse and underground fires.

Earliest mining under Castle Hill commenced in 1866, when a partnership of Lewis Thomas and John Malbon Thompson mined the shallowest areas of the Aberdare Seam using conventional Welsh bord and pillar methods. By a quirk of geography, Blackleg Gully intersects the seam and this provides a dual outcrop on either side of the gully that allowed easy surface access and development of mining both up and down dip. This formed the basis for the original Bundamba Mine on Portion 270 Goodna (Figure 4).

Figure 4. Mine sites targeting the Aberdare Seam below Castle Hill, pre 1900 (Whitmore, 1985, Figure 8).

From the outset, the mining of the Aberdare Seam was undertaken in two passes with the top and bottom coal plies, each around 1.5 m thick, being mined separately and the intervening 1.0 m thick shale band left in place.

This initial mining from Blackleg Gully provided direct access to a haulage track constructed along the base of the gully, with horse-drawn drays transporting the coal by a circuitous route to a barge loading station on the Bremer River, a distance of approximately 5 km to the north of the mine. From here the coal was barged to markets down river as far as the port of Brisbane.

The tonnage of the shallow coal available from the Blackleg Gully entries was limited, and in 1876 Thomas developed a new operation, the Aberdare Mine, to access deeper areas of the seam surrounding the reserve area from a series of shaft entries. These were the Aberdare No 1, No 2 and No 3 shafts. The No 3 shaft was also known as the Coolgardie shaft (Figure 4).

Efficient access to markets was secured by replacing the old dray and barge system in 1881 with a private spur line that connected the Aberdare Mine directly to the Brisbane to Ipswich railway line, which had been completed in 1874. The Aberdare Mine subsequently developed into the largest mine in the field, during its heyday accounting for almost 50 per cent of the coal production in the district. While the Bundamba Mine workings under Castle Hill lay dormant, the surrounding Aberdare Mine prospered and Thomas went on to pioneer new export markets through a newly constructed transport system extending through to Brisbane. This terminated at the South Brisbane coal wharf, which commenced operations in 1884.

The Aberdare Mine made Thomas’ fortune and he withdrew from active involvement to pursue other interests in 1894, after retreating to his newly constructed Brynhyfryd. This grand edifice sat in a dominating position overlooking Blackstone, no doubt as a tribute to Thomas’ success. But it lay directly above the old Bundamba Mine and later workings, and the seam which built Thomas’ ‘castle’ would ultimately lead to its destruction.

The Aberdare Mine continued with mixed success under the new management of the Aberdare Cooperative Colliery Ltd, during which time it concentrated its operations on the Aberdare No 3 shaft, otherwise called Coolgardie Shaft. Ongoing operational and management problems dogged the cooperative and seeking better prospects it subsequently opened the southern Aberdare No 4 Shaft, which also proved disappointing. Finally, perhaps in desperation, they returned to the Castle Hill area in 1902 to open a new mine on the underlying Four Foot seam. This was the Ladysmith Mine (Figure 5) that exploited the deeper coal under the former Bundamba Mine workings.

Figure 5. Mine sites targeting the Aberdare Seam below Castle Hill post 1900 (Whitmore, 1991, Figure 6).

The Ladysmith tunnel also proved a failure and the Aberdare Cooperative ceased operations in 1907. Mining of the area again remained dormant for a further four years.

Not to be discouraged for long, in 1911 a consortium from the former Aberdare Cooperative commenced a new Blackstone venture with the objective of exploiting the apparently large reserve of Four Foot seam coal that still remained under the hill. A new 130 metre shaft was commenced, conveniently located adjacent to the existing spur line at the mouth of Blackleg Gully. This was the Cardiff Colliery (Figure 5). The intention was to subsidise shaft development by commencing production from an extension of the existing Ladysmith tunnel and to ultimately connect the two workings to provide dual access and a readymade intake airway. The shaft ultimately proved that the Four Foot seam had totally deteriorated at that point and it finally targeted development on the deeper Rob Roy Seam at 205 metres. Unfortunately fate and poor ventilation overtook this venture with a major explosion on 24th January 1919 that claimed three lives and again closed mining under Castle Hill.

With the exception of sporadic attempts to reopen or rob the pillars of the old workings on the hill through to the 1940s, the seams under Castle Hill remained silent until the 1980s.

The final recorded phase of mining under Castle Hill was undertaken by the Rhonda No 5 Mine, which in the 1980s exploited the remaining area of the Rob Roy Seam by modern room and pillar methods. This accessed the Blackstone area via a long tunnel driven from an entry located to the east of the modern alignment of the (then recently completed) Cunningham Highway.

From the outset of mining in the 1860s, the issue of spontaneous combustion in the Aberdare Seam created problems for the miners in all of the mines around the site. Unfortunately for Castle Hill, the peculiar combination of seam geometry and topography that provided such easy access to the Aberdare Seam via Blackleg Gully also created ideal conditions for a ‘chimney effect’ to form wherever a ventilation path was created by poor mine layout or roof collapse through to the surface. This happened on many occasions, and as a consequence Castle Hill has been burning underground since the 1930s. The characteristic organic smells and wafts of steam that signal the surface vents from the fires have been a hallmark of the hill to this day.

Lewis Thomas and Brynhyfryd

For the suburb of Blackstone, Castle Hill and the story of its mansion have become emblematic of the life and contribution of the coal baron Lewis Thomas. Thomas, sometimes called the ‘Squire of Aberdare’ and the ‘Coal King’ was born in Talybont, Cardiganshire, Wales on 20 November 1832. After working in mills and the lead and coal mines of Wales, at the age of 27 he left his new bride to migrate to New South Wales in 1859. Here he worked in the gold mines of Ballarat before moving to the colony of Queensland in 1861.

In Queensland Thomas first worked at the Redbank Coal mine, but quickly moved into business for himself and contracted to excavate the Great Victoria railway tunnel near Rosewood. The tunnel through the Liverpool Ranges is still in operation today. By 1866 he had formed a partnership with John Malbon Thompson to open the Bundamba Mine at Blackstone, which he subsequently left in 1870 to develop mines of his own. By 1876 he had returned to Blackstone to buy out his old partner and expanded operations to create the Aberdare Mine, which ultimately made him his fortune. In the following year his wife joined him from Wales and he established himself in Blackstone, where he remained for the rest of his life.

Figure 6. Lewis Thomas, the ‘Coal King’, (John Oxley Library. State Library of Queensland Neg 110844).

Thomas’ legacy had many parts. He exhibited great acumen as a business entrepreneur, building his mine and developing the new overseas markets he needed for maintaining sales volume for the Aberdare coal. He was also instrumental in the creation of the integrated mine to port transport rail system that allowed the Bundamba coals to be transported by rail to Brisbane, and ultimately exported through the new coal wharf at South Brisbane that was opened in 1884.

As the largest single employer in the local industry Thomas was prominent in industrial circles and was a popular, reputedly somewhat enlightened employer. He was also a well-known philanthropist, putting much of his wealth back into the local community. He promoted the local public school, School of Arts, Welsh church, hospital and girls grammar school and supported the local eisteddfod. These are all projects which still remain today.

Thomas also entered politics, becoming the Member of Parliament for Bundamba in 1893, a position he held until he died in 1913.

In keeping with his status, Thomas built his palatial stately home on top of the most prominent hill above the top end of Thomas Street on the south side of the village, commanding a grand view across the Bremer River valley to the north. The three-storey home, designed by Architect George Brockwell Gill and completed in 1890, was named Brynhyfryd (pronounced Brin-Huv-Rid and meaning Pleasant Hill). Situated within 15 acres of landscaped garden, Brynhyfryd had more than 40 rooms, reticulated water, on-site electricity and even a hydraulic lift with a complement of staff to match. Lewis had earned his name of the ‘Coal King’ and his home, on the prominent position and visible for miles around, became known as the ‘Castle’. Its image has become a tangible, if now lost, local icon of the stereotypical local coal baron of Thomas’ era.

Up to and beyond Lewis’ death in 1913, Brynhyfryd played a prominent role in local society events and attracted governors, premiers and even Prime Minister Billy Hughes to its doors. It passed to Thomas’s only child, daughter Mary Cribb, and after her death in 1930 was sold off. It was eventually to be purchased by Rylance Colliery and Brickworks Pty Ltd in 1936 for the purpose of mining the remaining reserves under the property.

Unfortunately, this magnificent structure was severely damaged due to subsidence from the mining of the underlying Aberdare Seam, which occurred at shallow depth under the house site. Most of the house was demolished in 1937 with the remaining sections, including the billiards room, being bulldozed in 1973.

Figure 7. Brynhyfryd in its heyday (John Oxley Library. State Library of Queensland Neg 19718).

The 100 acres of land of the overall estate, which included the site of the ‘Castle’, remained vacant from the 1930s. However, this land was an attractive, albeit dangerous, ‘waste’ space used as an informal recreation area for trail bike and mountain bike riders as well as walkers. Over subsequent years, a number of developers acquired the land for the purpose of residential subdivision but the extensive subsidence issues – including smoking ground cracks, many tunnels and shaft entries – rendered the land unfit for development approval.

The future

Finally, in 2015 the latest owner – a potential developer – ultimately gifted the site to the Ipswich City Council for $1 on the understanding that it be developed for recreational purposes. Council embraced this concept and planning proceeded rapidly to convert the former wasteland to a safe educational and multi-use hiking and bike trail park. Stage 1 of the park was opened to the public at a large gathering on 20 November 2016, which also happened to coincide Lewis Thomas’ birthday.

The site is now formally named ‘Castle Hill – Blackstone Reserve’.

In developing the reserve, Council has installed formal tracks and professional signage, with the northern side of the hill and Blackleg Gully, comprising about 30 acres, being dedicated for the purpose of mining, education and recreational tourism. The remaining area to the south of Blackleg Gully is reserved mainly for mountain bike riding. Approximately 60 features around the north hill and Blackleg Gully have been signposted. The accurately positioned signboards cover general historical information on Lewis Thomas, the ‘Castle’, shaft and tunnel entry details and geological information including the down dip outcrop of the Aberdare Seam in Blackleg Gully.

Stage 2 and later works are planned to include the construction of toilets and a viewing deck, and to prepare an exposure of the outcrop of the Aberdare Seam to provide a clear contrast of the underlying geology that drove the development of coal field in the first place.

For visitors to the park, walking trails have been designed to highlight the major features of heritage and geological interest over a period of about three to five hours with a shorter 1.5 hour circuit designed to facilitate viewing by casual visitors.

The Ipswich City Council is promoting the new park as a valuable addition to the growing under of mining heritage sites which are being developed around Ipswich, the other recent example being the impressive Ipswich-Rosewood Coal Miners’ Memorial (www.coalminersmemorial.com.au) located in Limestone Park in Central Ipswich.

Bibliography

Grubb, K, “Coal Castle and Choirs – The Story of Blackstone in Queensland”, July 2014 (Willis Haenke Historical Foundation, Ipswich)

Ipswich City Council, “Blackstone Hill Draft Master Plan”, Ipswich City Council (ICC), 2016

Whitmore, R L, “Coal in Queensland – The Late Nineteenth Century 1875 to 1900”, University of Queensland Press, 1985

Whitmore, R L, “Coal in Queensland – From Federation to the Twenties 1900 to 1925”, University of Queensland Press, 1991

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