18-Aug-1988 -- The Simbari Gravity Survey was carried out in August 1988 as part of a petroleum exploration programme in Papua New Guinea. The survey was designed to provide an infill grid of regional gravity recordings and survey control was provide through the use of differential GPS. Mt Yelia was selected as one of the gravity station as its first order trigonometric data would provide survey control. The night before I was camped at Wonenera Government station

We were using state-of-the-art Trimble receiver equipment which consisted of a suitcase sized box, a receiver dish the size of a flying saucer mounted on a tripod and a portable generator to provide power. There was not 24 hour satellite coverage and the optimum satellite consternation occurred between 21:00 pm and 010:00 am each night. At ^ am on Thursday 18th August 1988 field hand Pete and myself breakfasted packed our gear and waited for the Hughes 500 helicopter to come from the Simbari base-camp to ferry us to Mt Yelia. Two ferry flights later and we were dumped on the top with all our survey gear by 9:00 am. The site was small and very very rocky with grass and scrubby bushes growing between large boulder making walking rather difficult. We spent all day finding space to erect two one-man tents, erect our radio and GPS satellite antennae. The only suitable ‘camping spots’ were 30 metres apart perched on flat boulders and the GPS antennae was affixed the Mt Yelia Trig station monument. After a lunch of cold tin of beans I scrambled downhill about 15 metres and found permanent standing water and caught glimpses of sulphur pits steaming in the misty cloudy mountain shoulder to the south. Dinner at 17:00 was rice, tinned fish, sweet corn, and beans – a good big hot plate full and it began raining heavily outside . An initial test of the GPS equipment failed and was eventually fixed by replacing 100 ft cable with a 30 ft cable. It was left running to record a few hours of data to make an accurate fix. I went to bed in a temperature of 8˚ C but once I had breathed in the tent for a while it became 10˚ C . None-the less I still wore 2 pairs of socks in my sleeping bag. I slept reasonably warm with occasional cold shivers. I was awaken at 12:50 by the computer beeping and after putting on extra clothes I found the message “RS232 connection problem” which I had little idea about. I abandoned readings. Pete’s tent was flapping dangerously and after securing it we had a cuppa tea and then walked the well trodden but still treacherous 30 metres back to my tent. It was no longer raining but very windy. Now that the generator is off there are no exhaust fumes I was able to close my tent fully. Moved around and found a less rocky part of the rock to sleep on. Temperature inside tent was now 6.6˚ C rising to 7˚ C with body heat and candle. Settled down to await the cold part of the morning. Goodnight Diary at 2 am.

The helicopter came to pick us up at 7.:30 am. Mike a New Zealander was a very experienced pilot. However during the loading of the chopper a gust of wind resulted in the chopper slipping so that Mike lost all contact with ‘earth’ and with no point of reference he had no choice to lift with me hanging off the skid outside the door. Seeing an opportunity of a flat bolder landing I abandoned the chopper releasing Mike of an extra 70 kg load resulting in him catapulting into open skies. This was not entirely a safe procedure and we all thanked our lucky stars that no lives were lost.

A professional paper describing some results of the survey and the visit may be found at Talbot, N and Carman,G, 1990, Application of Global Position System to PNG Petroleum Exploration: in Carman G.J and Z., 1990, Petroleum Exploration in Papua New Guinea : Proceddings of the First PNG Petroleum Convention, Port Moresby pp 73-82