Blowers

In the early 1970s a completely new kind of machine appeared on the mining fields around Lightning Ridge. Some were made by local miners such as Duncan Dickson and Bill O’Brien, others were brought from Coober Pedy in South Australia, where the first blowers had been built. Blowers operate like a large vacuum cleaner, using airflow through pipes to move dirt from the face of the drive to the surface.

After the engine and fan on one of earliest blowers disintegrated, causing serious injuries to its operators, safety became one of the main issues in efforts to design successful blowers. The first commercially built blowers in Lightning Ridge were made at Nexo Engineering, in 1973.

The clay is literally sucked up the pipes, just as a vacuum cleaner sucks up dust. The clay flies up the pipes into the cyclone where it spins around inside until it settles in the bottom. When the cyclone is full, the miner, working down in the mine, operates an electric switch which reduces the minus pressure in the cyclone, allowing the weight of clay to fall into the back of the truck. A counterweight then automatically closes the lid; readying the machine for work again.

John McCabe, 1979

I knew that they were being used safely in Coober Pedy, so I drove across to sort out the problem.… I built about 20 blowers with that design of fan before I developed the twin fan blower, which totally revolutionised the blowers. It cut fuel-operating costs in half while at the same time increasing efficiency. To date I’ve produced 140 blowers, while there has possibly been as many built around the field by individuals.

Knud Nexo, 2003

Improvements to Blowers

Several miners who built blowers made changes to the design, to improve their efficiency.

I experimented with the shape of the cyclone by making a small model and using a vacuum cleaner and rice grains to test how much separation there was. I tried using 12 inch pipes instead of 9 inch pipes, to avoid having to break up the larger pieces of dirt.

Gary Stone, 2013

I made changes to the hoppers and linings, pipe sizes and pipe joints.

Lawrie Cree, 2013

It is important to match the engine horsepower and speed to the fan characteristics, also the curved fan blade is more effective than straight blades.

George Mulder, 2013

Effectiveness of Blowers

Blowers were a radically new technology in opal mining. They performed many functions – moving dirt along drives to the shaft, lifting dirt to the surface, separating fine clay particles from the dirt, and ventilating the drives – which had previously been done by other machines.

Blowers could be set up more quickly and move much greater quantities of dirt compared with other mining machinery. Unlike many previous inventions, blowers were not adopted by all miners. They used huge amounts of fuel and demanded considerable mechanical skill to operate them efficiently. In the 1990s some miners switched from using blowers to using boggers (small dirt carriers) in the drives and superhoists to lift the dirt up the shafts.

The early blowers were inefficient, so many miners could not afford the high costs of fuel and maintenance. This changed in the 1980s when diggers were widely used – their output matched the capacity of the blowers.

Lawrie Cree, 2013

Lots of miners think the amount of fuel used by blowers make them too expensive to use, but if they are properly controlled and the pipes are airtight, fuel is saved. With blowers, drives can be narrower than with boggers, so less dirt needs to be moved. Also, blowers help move the air and make conditions underground more comfortable.

Gary Stone, 2013

When operating machines, especially diggers and blowers, you shift into material shifting mode. You focus on quantity rather than quality of the material.

Lawrie Cree, 2013