[4] In 1900 to allow the Richmond Vale Colliery site to be developed, J & A Brown applied for an act of parliament to allow the construction of a railway line from their existing Minmi to Hexham railway line (at a location later known as Minmi Junction) to Richmond Vale Colliery.

[10] John Brown spent large sums to ensure that his mining plant, colliery railways, steamships and engineering works were substantially built and in the forefront of technological development.

[12] In July 1914 sinking of No.2 shaft was completed and was 7 m (22 ft) feet in diameter and bricked from top to bottom and has been described as incomparable with any other in the country, even in its final days.

[15] Whilst the mine was nearing completion it was plagued by industrial action by the miners and only produced 1,500 tonnes (1,500 long tons) of coal during 1916.

[15] In February 1917 the miners had returned from strike and in the period up to August 1917 the mine had produced 7,000 tonnes (6,900 long tons) of coal.

The 1929 Lockout followed by the Great Depression, the 1949 strike, a recession in the coal industry and the change to mechanisation in the 1950s and 1960s were major setbacks which the colliery, and the South Maitland field generally, would not recover from.

It has been instrumental in returning some of the buildings and structures to their operating function in order to restore and maintain steam rolling stock and carriages and the rail line has been relaid.

External materials consisted of Richmond Main red face brick with some detailing in the form of window arches and sills.

[1] Unlike the other buildings at the colliery the bricks for the power station were obtained externally and were purchased from the National Brickworks Company Limited at Thornleigh.

The power station building was partially restored during 1987–88, which involved replacing the roof sheeting and repainting both internally and externally.

The 6000 kW Fraser & Chalmers turbine (order No.53504), 3-phase Wilton Alternator (serial No.44620) and the condensing plant arrived at Richmond Main in July 1927 at a total cost of £13529.

The winding set consisted of a 4 m (14 ft) diameter x wide drum powered by an 800 Volt DC electric motor.

Ordered in 1910 as part of the winding engine, the motor generator set was built by Siemens Brothers, Dynamo Works Ltd.

The building is a steel framed, corrugated asbestos sheeted structure with basement adjacent to, and northeast of, the turbine room.

[31] An extension of the conveyor to the new rail hopper also served a bin constructed to enable the loading of coal from trucks or ‘from grass’; this was the facility in use when the boiler house closed in 1976.

Ordered in 1926 to provide high-pressure steam for the new 6000 kW turbine, the boiler drums, tubes, stoker parts and structure arrived in 1927 at a total cost of £17913.

There is an additional group of buildings to the southeast of the turbine room, previously the location of the southern bank of original boilers.

The loco shed and adjoining store now form the main maintenance area for the Richmond Vale Railway Museum.

[1] A free standing single volume building constructed of red face bricks with typical detailing, including gabled end walls.

[1] A tall, freestanding concrete-encased steel-framed structure with red face brick infill panels and glazed walls on the western elevation.

[26] A 30 tonnes (30 long tons) hand driven Craven Brothers overhead travelling crane was purchased for £450 and fitted to the building.

[26] With the electric winding engine never being fully installed the bulk of the building was used for the undercover storage of large pieces of machinery.

[1] The cultural significance of the former Richmond Main Colliery in its surviving condition relies more on the complex as an expression of a particular era of region, industrial and social history than on the integrity of the remaining empty structures.

That era is the rapid and short-lived heyday of the establishment and development of the South Maitland coalfields in the first half of the twentieth century and of the mining communities and transportation networks that evolved to support that industry.

While Richmond Main can claim some degree of cultural significance in its own right, primarily through its links to John Brown and his intentions for it, its real strength lies in its ability to become that expression to present and future generations.

[37] Richmond Main Colliery was listed on the New South Wales State Heritage Register on 2 April 1999 having satisfied the following criteria.

[38][1] The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales.

The intention of John Brown to make Richmond Main his flagship and the showpiece of the industry can be seen to give the complex, a degree of representation for those other collieries, even in its partially ruined state.

Within the space of a decade, the region was transformed from a rural backwater to a vital element in the state's resources of steaming coal.

Without the usual constraints of existing investment or partially outdated facilities, John Brown was able to create Richmond Main as a corporate showpiece displaying "state of the art" coal mining technology and electric power generation.