1976: Two Awarua Radio masts to topple

Southland Times, 29 October 1976

Awarua masts to topple

The entire area within one kilometre radius of the Awarua radio station will be evacuated for a short time tomorrow while soldiers of the No. 2 Troop, 3rd Field Squadron, from Dunedin, demolish two 150ft radio masts.

All traffic on the Invercargill-Bluff road will be stopped, and aircraft will be warned away from the area.

The 15 soldiers, led by Lieutenant W.F. Thomson and including experts in explosives, will arrive in Invercargill tonight and begin preparations for the demolition early tomorrow morning.

The expect to detonate the 5kg of explosives necessary to topple the masts early in the afternoon.

The supervising engineer with the post office in Invercargill, Mr W.B. Ten Kley, said yesterday preparations tomorrow morning would involve sandbagging, placing the explosives around the legs of the masts and laying fuses.

There would be two blasts, he said. The first would cut the legs on one side to cause the masts to lean in the direction in they are to fall. A few moments later a second series of charges would be exploded to but the other legs and cause the masts to topple.

Mr Ten Kley said the area would be closed off for a short period, from just before the blasting until just after.

The exact time for the demolition could not be determined because it would depend on many things, such as the Army’s progress in preparing and the weather.

Rain would not bother the exercise, but it could be called off if there were high winds.

The masts to be toppled are two of three 150ft steel lattice masts erected in 1941 to carry the main marine aerial with the 500kHz or distress frequency. Time and corrosion have made them unsafe, and they were condemned five years ago.

They were not the first towers at Awarua. The first was a 400ft mast, which was 25 years old when it was demolished on March 24, 1938.

The Southland Times reported at that time that the mast was a well-known landmark throughout New Zealand. A large crowd watched the demolition, which was done by cutting through the steel stays which held the mast in position with a hacksaw.

When the mast fell, the crowd of onlookers surged forward to pick up nuts and other small pieces as souvenirs.

It was another three years before the new shorter towers were erected.

Mr Ten Kley believes they were assembled on the ground and levered into position using jury poles.

It has been estimated that the three masts each weigh about 10 tons.

They will be sold as scrap metal.

Mr Ten Kley said that as soon as they have been removed work will begin on erecting new 150ft masts. Bases are already prepared, and the sections are on site, ready for assembly.

These masts would be self supporting and much more slender than the present ones, he said.