From time to time we flew across areas of larger trees which snaked across the countryside marking the course of ephemeral creeks. These may only run with water a few days a year.
From ground level such a creek bed is most attractive. Above is a picture of our car parked in the middle of one about 25 km outside Broken Hill. It collects enough water during flash floods to soak deep into the subsoil and maintain the River Red Gums until the next time. As you can see it is quite wide, and must be a remarkable sight during a flood.
Dave navigates by eye from local knowledge, although he uses GPS readings for choosing turning points in the interest of fuel efficiency and no doubt instruments in case of fog or rain.
He has a prepared list of the maildrops, in flight order, clipped to his sun visor. This gives a checklist of the items to be delivered on that run, and also the pile of mail in the rear seat is layered in separate bundles in order of drops, making it easy for me to grab the mail for Joc at each stop.
He flies unerringly across this vast landscape, although we ourselves often could not distinguish the runways from the surrounding countryside until we were lining up for the descent, as in the picture at left.
Some of the airstrips still had standing water on them, and needed some care in choosing a landing zone. The red soil is extremely sticky when wet, and does not need a great amount of rain to render roads (or runways) impassable.
Obviously some experience is needed to judge when this might be the case, since while landing on a boggy runway might reduce the braking distance, it also might make the subsequent takeoff impossible!
Dave actually prefers landing on dirt strips to bitumen ones, as the latter create more wear on tyres. On the other hand, on dirt strips flying gravel is thrown by the wheels at the leading edge of the tailplane, which needs to be protected againts damage and abrasion with fibreglass tape.
About 250 km and quite a few deliveries out from Broken Hill we flew over the opal-mining township of White Cliffs. As we banked to land, we saw the thousands of mineshafts, each with its own cone of tailings.
We were picked up at the airstrip by the local tour bus and treated to a tour of the diggings before lunch. Not the sort of place to wander around after nightfall, it seems.
The only other passengers were two retired schoolteachers who live-in on remote outback stations during periods of intense work when the parents are too busy to co-operate with the School of the Air in teaching their kids. They really enjoyed being valued and appreciated by their hosts (teaching not being a very respected profession in City environments), and of course their pupils were extremely pleased to see a couple of new faces for a few weeks.
After these two left, we had the undivided attention of the tour guide, which was a mixed blessing.
He seemed reluctant to deviate from his fixed patter and answer the many questions we had, but on the other hand was an opal-miner himself and was able to explain the workings of the various machines around the place.
At right is an automatic tipping hoist. Miners used to have to work in pairs, one filling a bucket below with spoil, the other winding it to the surface with a windlass to tip it on the tailings heap.
This excellent invention enables a single miner to work a claim, the full bucket running up the shaft ladder from below, tipping its contents as it passes over the curve at the top, where it triggers a spring or weight which cuts off the winch power and returns the empty bucket back past the curve to descend again by gravity.
White Cliffs has a general store, several motels including an underground one, historic original dwellings, the inevitable hotel and several opal galleries/shops to serve those tourists who make their way here by road.
White Cliffs is also unique in having probably the worlds first heritage solar power station. The original design in the early 1980's had steam generated at the focus of parabolic mirrors and piped to a small turbine to generate power for the town. At the time it was the only such installation in the country, possibly the world.
However it was probably ahead of its time, and after a lot of engineering troubles the original design was scrapped and the parabolic mirrors were lined with conventional photovoltaic cells.
These proved to be very efficient, and in fact we were told that parts of the solar array are now regularly shut down to reduce the power output, as can be seen in the picture at left where some dishes are facing away from the sun.
After lunch at the store we joined Dave again, and flew out West towards the Mutawintje National Park, a rugged landscape whose caves and overhangs feature aboriginal rock art dating back many thousands of years.
The afternoon deliveries were much the same as the morning ones, except that we taxied up close to one homestead and had a chat with one of the station owners. Dave called her up on the radio when he was six minutes out from the runway, and she came out to meet us.
This particular homestead was adjacent to a (dry) lake which must have been lovely in the wet. The owner told us amazing tales of floods and last-minute escapes by plane from rising waters, food drops by helicopter and mass-drownings of sheep and cattle.
Her daughter had studied hard to take the necessary exams to be a National Park Ranger, and was one of 4 successful applicants (from about 400) for a job at Mutawintje - just "next door" to the station, i.e. most of a day's 4-wheel drive across remote and rugged country.
On our return to Broken hill, we got a special treat, Dave flying us over the open-cut mines and giving us a birds-eye view of the huge holes and vast scale of the workings. We asked him to buzz our roof next time he was flying along the South Gippsland coast.