Lava Plains Field Trip Reports

Two reports from same field trip in 2016

From CMLC Newsletter Jul 2016

Members on field trip.

  • Allan Gale,
  • Michael Hardcastle,
  • Demetri Kanellos,
  • Amanda Pearce,
  • Stuart Howe,
  • Ken Vaughan.

Both Michael’s and Allan’s reports follow

Michael Hardcastle’s Report

Demitri and I met Allan in Mareeba. We left about 12:30, Allan & I in his car towing the camper trailer and Demitri following in his van.

After the scenic drive over the lush green hills of the dairy country we passed through Mt. Garnet. The landscape changed to the drier beef cattle country and we continued on through the Forty Mile Scrub and on to the Lava Plains Sapphire Fields.

We arrived about 3:00pm . Stuart and Amanda had arrived the day before and had already set their camp and Ken’s camper-van was parked nearby. They were all down at the creek busy fossicking.

After a site inspection, Dimitri parked his van and we helped Allan erect the camper trailer and annex as quickly as possible. By late afternoon we had just finished and Ken, Amanda and Stuart returned from fossicking. We had a few drinks and a chat around the fire. Ken said, looking at the clouds, that it might rain. I said, “No it rarely rains out west.”

Anyway, just on dark, it started sprinkling. We retreated under cover , had a quick bite to eat from the tin can. Due to the drop in temperature, we went to bed early and I snuggled into my cosy warm swag and fell asleep listening to the rain falling on the tarp roof. Suddenly I was awoken by a loud bang, a huge whoosh and water splashing over me. The tarp had ponded and collapsed under the weight of many litres of water and it was just pouring with rain.

Battle stations! Allan and I both jumped up and worked together to rectify the damage, replaced a bent roof support and put in many tent pegs that had pulled out of the ground and had to be hammered back in. The rain was just bucketing down . It must have looked a funny sight. I was running around in a tee shirt and jocks . The tent sprang a leak and all of Allan’s clothes got wet. Fortunately we could see the funny side of things. We didn’t sleep as well for a while for we kept on checking the roof for ponding.

On Sunday, Dimitri, Stuart, Allan, Ken & I walked down the road to the boundary to check we were fossicking in the right area. We did a bit of specking and picked up small pieces of sapphire. Then Stuart and Amanda left for Cairns.

On Monday we started to fossick at the creek . Due to the rain, it was good specking conditions and some locals from Ravenshoe came out to try their luck. They walked out of the bush about 20 metres in front of us and picked up a nice sized blue sapphire.

It was very muddy and we were walking around with three inches of mud stuck to our boots. It was like trudging around in lead boots but that’s all part of fossicking and was good fun.

The next four days we spent exploring and fossicking, We tried to sieve soil but it was too muddy

Allan Gale’s Report

Michael, Dimitrios and I met Stuart, Amanda and Ken at the layby entrance to the “Mines Hill” fossicking area on Lava Plains Station. Camp was set up and a pleasant evening ensued till the rain set in.

Allan And Michael’s camp suffered a minor mishap during the night with a bent spacer rod and pulled pegs due to pooling rain water. Stu said he saw Michael & I conducting running repairs in the rain but wasn’t going to get out of his nice warm, dry bed to help us. Thanks Stu. Truthfully though, neither Michael nor I are likely to win any wet T-shirt competitions. We probably looked like a couple of wet baboons.

Given that we had approximately 40ml of rain over-night (estimated from the depth of the water in a fossicking bucket next morning), it was decided that specking was the best plan for our Sunday. Amanda stayed in camp and the rest of the party set off after breakfast, use of the amenities (long drop dunny dug by our resident construction engineer, Michael) and the ablutions block (shower).

The group proceeded down the track from the gate, “eyes down and looking” as the track started down the ridge. All found pieces of colour …though nothing special… before we reached the sign advising of the end of the fossicking area. “Peter” our local mining warden had advised that the limit of the fossicking has been marked by paint on trees and we were able to follow the marked trees east down to the gully. The group proceeded to spec back up the gully.

Most of us were considerably taller by this point due to the glutinous nature of the ground. The mud stuck to our boots even worse in the gully and we were forced to stop to clear off the mud while we were working.

Stu left us about lunch time and he and Amanda headed for home. The next few days were spent fossicking and exploring without incident

Report by Robert O’Leary in 2018

From CMLC Newsletter Apr 2018

Easter 2018 at the Lava Plains

The original plan for the Easter weekend was for the club members to go out to fossick at O’Briens Creek near Mount Surprise. Here topaz is the target. Also nice crystals of smoky quartz can be found and aquamarine if you are truly lucky or know the secret spot!

However it was not to be this time around. Cyclone Nora, which formed in the gulf had, only days before Easter, crossed the coast near Weipa and fizzled out between there and Cairns. Cairns had its best flooding in decades. The Mount Surprise area didn’t miss out and had it’s own record floods. A campervan was totally submerged and of course the causeway was uncrossable. If the toilet paper is flooded, forget it! O’Briens Creek was closed….a new plan needed. Lava Plains was the decision.

Five of us went out there on Good Friday. I arrived in the mid-afternoon and had already specked a few little sapphires when Michael and Nicki arrived in the gully. I could hear Mike’s tutorial to Nicki over the hill. Later that evening, Ken and Anita arrived. The camping situation ranged from basic to luxurious. Mike, Anita and I tenting, Nicki in her decked out trooper and Ken in his shiny new comfortable camper with kitchen and entertainment. Michael’s campfire skills were exemplary and we cooked and told yarns around the fire until late. Our new mate Helmut from Austria was also camped out and fossicking. It was his 7th trip to Lava Plains this year and he didn’t hesitate to show us his success or share information, the “retirement stone” and Austrian emeralds firmly guiding his thoughts and our dreams.

The next day we were all out early with lunches packed. Michael led us down to the fossicking area which centres on a gully running into the property for about 1km. The gully starts uphill and skirts the volcanic vent of the volcano which has been extinct for 300 000 years. This vent is said to be the source of he the very local sapphire deposit. The entire length of the gully has been machine mined. Now a small creek runs down it after rain. The ground here is decomposed lava, heavy, muddy dense clay. Impossible to dry sieve. Mostly specking on eroded surfaces is the method of fossicking.

Everyone was finding a few small sapphires and many small associated spinels. The weather was nice - not too sunny. We were all having a great day. Midway down the field, in the middle of the gully there is a small tree with an even smaller waterfall under it. On previous trips, I have come to know it as the “sapphire tree”. It is the perfect spot, out of the sun for lunch. Last time on a lunch break, I did some sieving here and found 30 to 50 small sapphires.

The first sieve yielded a tiny but hope-giving sapphire. On flipping the second sieve….there it was!!Blue, so blue and shining wet from the creek and glistening in the sun. A sapphire , small, but a perfect terminated crystal of such a nice colour, sitting in a pile of black spinels. I excitedly invited the others to come have a look.

At about 11:30am I was ahead of the group and decided to go for a walk up the bank near the tree, not expecting to find much as I had found one here before. Barely studying the ground and walking much faster than usual, I glanced down and spotted a dark rock of hexagonal structures. It turned out to be the best sapphire I have ever found. At lunch time “show and tell”, I was the winner! Keen eyed Anita found two nice ones while eating under the tree. My stone even impressed Helmut that evening.

Sapphire, the blue crystal form of the mineral corundum is found in many places up and down the Great Dividing Range on the east coast of Australia. Prominent areas to find them include Tasmania, the New England region of New South Wales, the Central Queensland Gemfields of Queensland and of course the Lava Plains of North Queensland. Sapphire forms under vast amounts of heat and pressure, deep in the Earth. Volcanic activity brings them to the surface.

A pure crystal of corundum will be colourless, however this is rare. Sapphires occur in many colours, not just blue. The blue colour in the stone is from small traces of titanium and iron. The presence of traces of chromium will make a growing sapphire crystal red. This is known as a ruby.

The next day it was cloudy and we got up late and had a long slow breakfast. The Mines Inspector paid us a friendly visit and admired our finds. We also learned of Michael’s golden ambitions. I’m Keen!

After a late start we left camp and headed left along the fence line. Today was exploration day and we were all keen to see the limits of the fossicking area. We went right to the boundary and around the left side of the vent. No sapphires were found. Given the proximity of the vent. I am sure they are there in abundance This trip, all the sapphires we found were in areas of erosion. Just after heavy rain is certainly the best time to fossick here. There is only one catch, you must enjoy mud and the possibility of high-heeled boots.

That afternoon we took advantage of the water in the creek and found some tiny beauties. We all found some by specking too. A trip up Spinel Creek didn’t disappoint with little pieces of black shinies in most traps. The odd small sapphire surprised us and kept us excited. My final find was a 6 carat dogtooth from a shallow digging at the terminus of Barrel Trench/Creek. It certainly made my trip. The rest of our group were staying another night. I was heading home, so I bade them “good luck” and “adieu” .

Robert O’Leary

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