Electricity in Illawarra Coal Mining

The mining of coal entails the expenditure of much work.  Once tunnels have been driven to access a coal seam, the coal must be cut, loaded on to transport, and taken to the surface for either treatment or dispatch to users.  The mine workings themselves must be lighted, ventilated adequately to remove dangerous gases, and drained of any water which might be encountered underground.  In the early mines of the Illawarra, these needs were met in a variety of ways, for example lighting through the oil lamps of individual miners, and ventilation through the use of vertical shafts to the surface, with fires at their base to induce convective airflow up the shaft and hence through the mine.  Otherwise the needs were met by the labour of men, horses and pit ponies, with one major exception.

Mt Keira Incline ca 1880

From the collections of the Wollongong City Library
and the Illawarra Historical Society P02224

The topography of the Illawarra generally, and the location of coal seams meant that gravity could be employed, by recovering work from the lowering of product coal from the mine surface facility to the coastal plain below for subsequent transport.  So this surplus mechanical power, generated by self-acting incline haulages, could be and was employed in a variety of ingenious ways to operate surface and underground equipment and transport the mined coal to the surface.  Supplementing this in some cases was steam power from coal-fired boilers driving surface equipment,

Boiler Plant, Bellambi Coal and Coke, 1909

This still however largely left to manual labour the task of cutting the coal for its transport out of the mine.  Coal mining was a very labour intensive industry, as shown in one cost analysis of the day.  The work was not only hard, but often dangerous, adding to the motivation to find other ways to cut coal.  A variety of devices were developed for this purpose, using for their power source either compressed air, or electricity.  The former might be supplied from steam-driven compressors located at the mine surface, but the latter implied the construction of local power generation facilities.  The section which follows describes the installation of these prime power generation facilities at a number of major Illawarra mines.  The development of electrically powered mining machinery is a significant story in its own right, and an account of this may be found here.

But the coal mining industry’s link to power generation extended further than supporting production.  An important element of the industry, the manufacture of coke (often to consume the fine coal generated in mining), was one with opportunities for energy recovery from the coking process – and three significant Illawarra coking plants were so equipped, generating power from the waste heat from coking operations.  In more recent times, initiatives aimed at improving safety by removing methane from coal beds before mining led to the possibility of power generation from the gases produced by that drainage.  Significant power generation facilities turned an otherwise dangerous byproduct into power to feed the state grid.  This operation is discussed further below.

Installation of Mine Electrical Plant

The first local generation facility in the Illawarra was that at the Mount Kembla mine, in 1903.  Sadly that mine had the previous year been the location of Australia’s worst mining disaster in which 96 men and boys were killed in an explosion from methane and coal dust ignited by a naked-flame miner’s lamp.

Mount Kembla Colliery Boiler Power Plant -1903

The new facility (coal-fired boiler plant and generator) was described as a most up-to-date plant, generating power at 2200 V and 250 V for use in both surface and underground facilities including extensive lighting, water pumps  and coal cutting machines.  The plant generated AC power at 50 Hz.  (Power plants of the time adopted either the direct current (DC) system, or the alternating current (AC) system, operating at a frequency of either 25 or 50 cycles per second. The AC system operating at 50 cycles became the preferred option, and the standard for AC power supply systems. The output supply voltage chosen was nominally 2,200 volts, with 415/240V for supply to drive motors and lighting systems.)

The following year, 1904, a power house was erected at the North Bulli Colliery, to supply two coal cutting machines, supplied by the Jeffrey Manufacturing Company (USA).  Little information is available on the composition of this power facility.  Further plants followed at the Mt Pleasant mine, and at the South Bulli, Bulli, , Wongawilli, Coalcliff and Metropolitan Collieries as coal cutting machines powered by electricity or compressed air became available and were installed in the latter mines.  Over the years, the demand for electrical power was to grow as equipment became more widespread and more complex.

South Bulli Colliery Power House

At South Bulli a boiler house and steam engine had been installed as a part of the original mine development in 1887.  The later plant was a relatively large plant, located above the pit top area of the colliery.  It comprised four hand fired (coal) Lancashire steam boilers, and generating plant having an initial output of 2000 kW, later increasing to 2700 kW at an output voltage of 2300 V AC.   Coal for the boiler plant was delivered in wagons, drawn by an incline rope haulage system up to the power house from the screening plant below.  Water for the boiler plant was delivered by pump and gravity to a secondary dam located adjacent to the power house from a dam on the Bellambi Creek, behind the escarpment.

Boiler Plant and Haulage Engine, South Bulli Mine

Bellambi Coal and Coke Company

 

The South Bulli power house provided the steam required to drive the generating plant and other surface plant, and supply the electric power required for both surface and underground installations including the mine roadway, lighting, rope haulages, air compressors and coal cutting machines.  Not all equipment though was electrically driven.  A Walker mine ventilation fan, of UK design and driven by a 450kW steam engine, was installed in a building adjoining the power house. This mine fan was claimed at that time, to have been the largest such fan in the southern hemisphere

South Bulli Colliery Power House and Mine Ventilation Fan

In 1913, in a first such initiative for the Illawarra, electric power from the South Bulli power house was provided to the Bulli Shire Council to supply the major portion of the Shire area, from Bellambi to Stanwell Park.  This arrangement led to Bulli being the first country shire area, to be supplied with electricity.  This supply was terminated in 1950, as the quantity of power required to support the Shire demands for the supply of electricity had increased, and was being sourced from the PWD Port Kembla power house.  That was in accordance with requirements of the 1935 Electricity Supply Act which included a clause forbidding the supply of electricity from privately operated power stations.[1]

The South Bulli Power House closed in 1954, when the existing steam driven mine plant had been replaced by the electric motor and the ongoing development of the mine included an increasing demand for power and access to the PWD Electricity Supply network to satisfy that increase.

Energy Recovery – Corrimal Coke Works

Belliss and Morcom Steam Engine and Generator, Corrimal Coke Works

1912 saw the first of a new type of power generation in the Illawarra, and one very innovative for its day.  The Corrimal coke works opened in 1912 as part of the overall Corrimal mine development.  The coke plant was of the beehive, total combustion type where the volatiles driven off the coal in the process of coking were burnt fully in the oven system, thereby providing the energy for the coking process, and also generating a very hot off-gas stream from which energy could be recovered.  This was implemented for the first time in the Illawarra at the Corrimal works.  No record of the type of heat recovery unit used there is available, but it is likely to have been similar to an unfired water-tube boiler, generating steam to drive a steam engine for power generation.

The power plant of 400 kW capacity was arranged to supply 250 kW to the colliery and 150 kW to the coke plant.  From 1918 to 1955 the plant also provided electricity for street lamps to the adjacent council.  In 1930 an additional eight ovens were added, and with them in 1932 a 1000 kW turbo alternator and steam boiler plant was installed.  The supply to the local council ceased in 1955, being replaced by that from the PWD Port Kembla station.

Steam Turboalternator – Installed 1960, Corrimal Coke Works

Metropolitan Colliery

 

In 1889, the Metropolitan Colliery in Helensburgh commenced production, with initial equipment and plant including a steam power plant.  It is not clear when electricity generation was added to the power house but it is likely it was around the same time as those above.  The generation that was installed was to supply the mine (underground and surface facilities) and the nearby township of Helensburgh and a local sanatorium, supply commencing in 1913.

Metropolitan Colliery Boiler Plant 1906

From the collections of the Wollongong City Library
and the Illawarra Historical Society P16545

 

Mt Pleasant Colliery

 

The Mt Pleasant colliery opened in 1861.  In 1916 a coal-fired steam power house was built near the bottom of the mine incline adjacent to the present (2018) North Wollongong TAFE College complex.  The power house consisted of one 352 kW, 50 cycle, 6.6 kV alternator driven by a condensing steam engine along with a boiler plant, condenser, and cooling tower.  A 6.6 kV overhead transmission line was erected beside the incline haulage roadway from the power house to supply plant in the pit top area, which included the electric drive motors fitted to the endless rope coal haulage, and main and tail man transport haulages, previously driven by steam engines.  In 1921 a second 352kW, 50 cycle, 6.6 kV alternator driven by a duplicate condensing steam engine was added, increasing the capacity of the power house to 704kW.  While the mine itself was to close in 1933, its power plant later lived a second life.  When Australian Iron & Steel (AI & S) acquired the Mt Keira mine in 1937, the Mt Pleasant power house was rehabilitated in 1938 to provide electrical power to Mt Keira for development, pending the erection of the 33kV overhead transmission line from the AI&S Port Kembla steelworks to each of that company’s mines.

Mt Pleasant Colliery (Power Plant in background)

From the collections of the Wollongong City Library
and the Illawarra Historical Society P19938

Coalcliff and Wongawilli Power Plants

The Coalcliff mine (later to become one of Australia’s largest producers) installed its electrical power plant in 1916.  This installation, a direct current (DC) facility, was built to service lighting both surface and underground, and underground mining machinery.  Little detail is available on the original installation other than that, like most others, it was based on coal-fired steam generation.

The last significant colliery power house to be built was that at Wongawilli.  In 1916 the Hoskins Iron and Steel Company (then operating the Lithgow steelworks) purchased an existing small mine at Wongawilli and erected  a coke ovens plant (of the beehive, total combustion type) to use coal from the expanded mine to produce coke for their operations at Lithgow.  In 1920, as a part of that development, a heat recovery system like that installed at Corrimal coke works was installed to support a 308 kW power plant to supply the mine and coke ovens.  The power house closed in 1938 when the coke oven plant shut down as a result of the commissioning of large-scale byproduct type coke ovens erected at the Hoskins steel plant.

Wongawilli Coke Ovens 1934

From the collections of the Wollongong City Library
and the Illawarra Historical Society P20762

So the period from 1900 to 1920 saw the development of substantial power generation capacity driven by industry’s need to support rapidly developing technologies in mining.  Though later to be replaced by an integrated, state-wide public system, the generation systems installed were much instrumental in aiding the introduction of these new technologies, and with that the development of coal mining in the region.

One significant power generation initiative was however to remain with the coal industry.  The development of coal mines and the mining of coal , west of the escarpment, that borders the Illawarra coastline, has been accompanied by a significant increase in the quantity of methane gas contained in the coal seam. These seams, were originally mined from their outcrop on the escarpment are now lying deep below the surface.  This has led to the need to drain this gas prior to its mining by in seam drilling prior to mining and deliver the gas to a Gas Drainage plant erected on the surface of the mine.  This collected gas was initially used as a fuel to supply gas turbine powered electricity generating plants first at the Westcliff mine, and then at the Appin mine.

The gas turbine plant at Appin was later removed and replaced by gas engines for reliability reasons.  The photograph below shows the current plant erected at the Appin East Colliery at Appin, NSW.  This site has the capacity to generate forty (40) MW of electric power using a large number of gas fuelled reciprocating engines each coupled to a alternator having an output capacity of one (1.0) MW, feeding directly into the NSW state electricity power grid.

A second plant of this type, having the capacity to generate fifty (50) MW of power has been erected at the Appin West Colliery at Wilton, NSW.

Mine Gas Power Plant Appin East Colliery- Appin, NSW

Electricity in the Illawarra Metallurgical Industries

Metallurgical industries by their nature tend to be energy intensive – some in thermal energy, some in electrical/mechanical power and some in both.  Of the major industries covered here, the Port Kembla steelworks and Electrolytic Refining and Smelting (ER&S) fall into the latter category, as did the Dapto Smelter on a much smaller scale.  Other industries, particularly those engaged in metal rolling and forming, tended to have higher mechanical/electrical power demands, and to be purchasers of electricity by virtue of the nature of their loads.  Among the early Illawarra metallurgical industries, private, on-site power generation was largely confined to two major operations, ER&S and Port Kembla steelworks.  As with the miners before them, the basic reason for their power generation was the absence of any other (external) supply

The first local metallurgical industry was the Smelting and Refining Company’s Dapto smelter.  Its mechanical power demands largely centred around two blast air blowers, units capable of delivering 6,000 cubic feet per minute (10,200 cubic metres/hr) to each of their two furnaces.  The blowers were steam-driven by Fowler compound condensing engines of 240 HP.  Electrical power use was confined to extensive lighting (some one hundred 16-candlepower lights and seven 1000 candlepower lights), thereby allowing night work in the plant, the first such use in Australia.  Power for these lights was provided by a steam engine powered DC generator which went into service on 4 May 1897[2].

It is a reflection of the novelty of broad area lighting at that time that the local newspaper correspondent felt compelled to write, albeit jocularly, of the effect of the lighting:

The use of area lighting was most important to the economics of operation.  There is no record however of the use of other electrical devices or equipment as was to be the case with the larger Port Kembla smelter which followed.

In a second major initiative, a major test/demonstration facility was built and operated utilising new catalytic technology to remove low levels of methane from mine ventilation air – levels too low to be able to be addressed by the technology described above.  It was the first such facility built in the world, and while no longer operating, successfully demonstrated the technology.  Further information on this project may be found here.

Electrolytic Refining & Smelting

Not surprisingly, the economics of power generation are a central issue for an electrolytic refining plant.  In the case of the Port Kembla ER&S plant, power costs were considered to be high relative to, for example, US costs of the day.  The new plant commissioned in 1909 was well equipped with power generation, not only for the electrolysis tanks, but also to power a wide range of cranes, pumps, material ‘trams, hydraulic systems and lights.  It was estimated that power could be produced by that plant, from local coal, for £11/kW.yr – as compared to the £4/kW.yr paid by competing producers for hydro-based power in the US.  The local power price was considered to be high, in large part due to the high price of coal, as compared to that available again to US competitors.  The manager of the time instanced the case of plants in New Jersey being able to buy what was said to be a lower (7%) ash coal at 5s 6d per short ton (6s 2d per ton) for their power production.  Twenty years before, a five year contract had been signed for the output of South Bulli colliery, at 6s 6d per ton, somewhat supporting the manager’s contention.  As well as the ER&S operations, the power plant supported also the other two Mt Morgan companies, Australian Fertilisers Ltd (AFL) and Metal Manufactures Ltd (MM).

The power plant itself included

  • five large Babcock & Wilcox water-tube boilers, with superheaters
  • two British-Westinghouse DC generators of 550kW each, driven by Belliss and Morcom triple expansion engines,
  • a turboblower to supply blast air and
  • standard and high pressure compressors to drive airlift pumps, and airlifts for materials handling.

The plant was significantly more mechanised than had been the earlier, smaller smelter.  In the early 1930s, the two Belliss & Morcom steam engines were replaced by a sungle Belliss and Morcom steam turbine driving both generators.[3]  Then, with the development of the state system through the Electricity Commission of NSW, the plant began taking AC power (at 6600 V) from the Commission system, phasing out the original DC generation.  By 1960, the DC generation was gone, with three Commission feeders into the ER&S main substation.  Also feeding that substation was a 3.6MW steam turboalternator, the substation in turn supplying power to ER&S, AFL and MM.  (Steam supply came from an ICAL 18 t/h boiler with two backup B&W 9 t/h boilers.)  DC requirements for the electrolytic process were supplied by a 6.6kV, BTH germanium rectifier supplying 8,000 A at 130 VDC.  That was backed up by a similarly rated BTH motor/generator set.  Any remaining DC drives in the ER&S plant were supplied by two 150 kW mercury arc rectifiers, other drives having been converted to 415 V[4].

It is not clear when the system of group supply was terminated but is likely to have been as the two former Mt Morgan associate companies became entirely separate in ownership terms from ER&S.  It seems likely also that the internal power generation was ended in 1966 when the new Japanese owners of the former ER&S took over the plant.

Hoskins Iron and Steel/Australian Iron and Steel.

Integrated steel plants differ from others described here in one important respect – the processes employed generate substantial quantities of combustible byproduct gases, the effective use of which is central to the economics of production.  The management of byproduct fuels may often require their conversion into electricity, in the situation where other plant thermal loads are less than the available fuel supplies.  As well, the nature of some of the processes requires that a secure supply of electricity be available to ensure ongoing safe plant operation.  For that reason, power generation is a common feature of such integrated plants – here of course with the basic factor of there being no available alternative supply.

A multi-function power house was a feature of the new Hoskins steel plant from its first days in 1926.  This included boiler plant, blast furnace blowers, a turbogenerator, pumping systems for power house and blast furnace cooling, and other basic service provision such as compressed air.  The first boilers (initially three, followed shortly after by four more) were both coal and blast furnace gas (BFG) fired units of some 18 t/h each, at 275 psig (1.9 MPa) and 300 C.  The new blower was a turbine driven Brown Boveri (BBC) radial machine capable of 101,900 m3/h at 207 kPa, and had as a backup a machine brought from Lithgow, a Thompson blowing engine.

Switchboard AIS No 1 Power House ca 1940

From the collections of the Wollongong City Library
and the Illawarra Historical Society P20759

The latter though of lower capacity than the BBC machine (76,000 m3/h at 172 kPa), was a truly massive piece of equipment.  The drive was a two cylinder horizontal compound engine with a HP cylinder of 36″ diameter, an LP cylinder of 66″ diameter and a stroke of 48″.  The air side comprised two double acting cylinders of 84” (2.1 m) diameter each, the unit running at 100 rpm.  In all, it weighed 330 tons, and required a concrete foundation of some 1400 tons.  The engine nominally shared a condenser with the first generating plant, a BBC 2,500 kW turboalternator.  In practice, the Thompson machine seldom ran condensing.  Other plant installed included cooling water pumps (salt water being used for virtually all cooling duties), compressed air plant, and boiler feedwater.

This power house (No 1 Power House) was of significant capacity at startup, but was to grow further over ensuing years.  Boiler plant was uprated with units such as air heaters, and the availability of ‘surplus’ BFG led to the installation of a second-hand Metropolitan Vickers 5,000 kW turboalternator.in 1930.  In 1934 further boiler upgrades were carried out, with the introduction of pulverised fuel (PF) firing.  In 1935 a second 5,000 kW alternator of British Thompson Houston (BTH) make was installed.  A new B&W boiler of 45.3 t/h was commissioned in 1936.  A second unit of that size but from International Combustion was installed in 1938, and in that year also a second BBC turboblower (rated 110,400 m3/h at 152 kPa) was installed for the new No 2 Blast Furnace.  The additional BFG from that furnace led to the installation of a fourth turboalternator, of 12,500 kW.  The growth of electrical load led in turn to a major upgrade of electrical distribution, including the supply of electricity to the Wongawilli mine site noted above.

Boiler Feed Grates, AIS No 1 Power House

From the collections of the Wollongong City Library
and the Illawarra Historical Society P20761

The existence of power generation capacity of some significance in relation to the local load had an important but perhaps unexpected consequence during the Great Depression of the early 1930s.  AI & S normally generated electricity from blast-furnace gas (BFG) as a byproduct fuel, and it was economic for them to sell power to the local PWD grid.  Even later when operations were reduced markedly, they were able to generate from their own coal sources.  This provided a revenue stream at a time when the demand for their actual product was very low indeed.  It also benefited the PWD, by allowing them to defer capital expenditure on new plant which would otherwise have been required.  This sale though was not without some controversy from competing private interests.  An interesting article by Don Reynolds outlines this, in a broader history of power supply in the Illawarra and Southern Highlands.

The next step in power generation in the steel plant was intended to be a major one.  With the planned development of Flat Products rolling mills with high and variable power demands, it was recognised that the available state supply was likely to be inadequate.  It was therefore decided to build a new power station to cater for this load.  Equipment for the station was ordered, and site preparation and construction work commenced.  The plant was to comprise four new boilers, each of 77 t/h; two 30 MW condensing turboalternators; and a 7.5 MW back-pressure turboalternator.  The planned 67.5 MW capacity was more than double the existing capacity at the No. 1 Power House.  Notwithstanding the commitments made, and the commencement of site work, the project was ultimately cancelled at high cost to the company.  There was a reluctance on the part of senior BHP management to commit further capital on what was already a major steel production project.  More particularly though, the State government were at that time working on the creation of a State Electricity Commission (as discussed below), to integrate the various individual facilities in the state and provide a basis for system growth.  The government argued strongly that it should provide the power needed for plant development, and was in a strong position to do so because of the necessary approvals and agreements required for the development of the Flat Products plant.  The situation remained however that the loads imposed by the Port Kembla plant were at that time large relative to system capacity, and it was noted that the rolling of each coil of steel at Port Kembla could be observed at the state system  control centre in Pyrmont.

The ongoing growth of the Port Kembla plant led to the development of a second power house (designated No 2 Blower Station) in the new No 2 Steelworks area.  The initial development comprised two 68 t/h boilers and two 13 MW (17,500 hp) turboblowers, with no power generation.  Later development in the early 1970s saw the addition of two 110 t/h boilers and a 30 MW (40,000 hp) turboblower, (for the No 5 Blast Furnace) again with no additional generation.  That was to come later in the 1980s, when a 16 MW turboalternator was installed, and a 6 MW multipurpose, back-pressure turbine driven compressor/generator set was installed.  A further 140 /h coal and gas-fired boiler was installed in the same period.  The 1980s also saw the installation of a 5 MW turboalternator driven through the recovery of top gas pressure from  the No 5 Blast Furnace, as an energy saving measure.

The 16 MW machine installed in 1980 had an interesting link to other local operations.  In the early 1950s a 15 MW turboalternator in the Port Kembla Power Station failed spectacularly such that both the turbine and the alternator were not repairable.  The unit was replaced by a new 16 MW machine, which operated until the Port Kembla Station closed around 1970, and was later purchased by AI & S and installed in the No 2 Blower Station..  A second smaller unit with historical links in No 2 Blower Station was a 2 MW condensing steam turbine driving a general service air compressor.  The turbine had originally been installed in the 1950s in the power plant of the Corrimal Coke Works.

Notwithstanding the growth of generation capacity over the years, electric power demands for the plant in general had grown much faster, with a total load around 180 MW (compared to the plant’s ‘firm’ generation rating around 30 MW) , largely supplied from the Electricity Commission, such that the principal role of power generation had become process energy recovery, plus a quite modest level of dedicated generation for security purposes on critical plant.  The volume needs of the industry were now met by the state system which had developed over the period, as described here.

[1] Wollongong City Reference Library “History of Electricity Supply” Manuscript Folder Notes etc. MSS 1533.

[2] DKR Personal Notes

[3] DKR Power Dept History`

[4] Anon, Description of Plant and Operations, 1961 UOW Library