About the cave
Tassie has some beautiful caves, which are also known for being somewhat of a summer-only destination. Not that it’s any warmer underground in the JF in summer…but it can be a touch drier. The cave pictured above is JF398, the entrance of which was discovered and tagged back in the 80s. Earlier this year the massive boulder pile that fills the entrance down to 35m below the surface was passed, and the cave named Boulder Jenga. Exploration occurred during one of the driest periods of the year. A small stream above the entrance sinks into the cave and recent rain made our trip last weekend a little wetter than initial exploration.
About the trip
With the key local participants back from overseas caving jaunts, Dave, Sandy and I travelled down from Melbourne to meet Dickon and Andreas in Tassie. The objectives of the weekend were to continue surveying what had already been discovered, have a look at the leads and (of course) take some photos. When rigging the pitch the weekend before Dickon and Andreas had discovered a small sump entrance where previously there was a large draft. This likely means that Boulder Jenga is a summer cave with the way on blocked up with water during winter.
Once we’d squeezed our way down through the boulders and whizzed down the 60m pitch we descended into the base level streamway passage. In addition to the camera gear we’d lugged a small 3L tank and regulator along with us. Surveying and photos make for slow work and by the time we hit the end of the cave we were all a bit chilly. This led to a stand-off over the tank and some discussion on who was stupid enough to jump in the water and see if the sump was a duck under.
I signed up and we all headed through the roof sniff in 8 degree water and 3mm wetsuits. After a bit more streamway passage it became apparent the tiny little mud pool was considered “the way on” and I began to rethink my volunteerism. The idea of taking the tank all the way back out again without using it was a bit painful. While we tested various pools of water for signs of flow, Andreas volunteered to jump in. He made it to about 2m down to report lots of mud and no obvious way on. It’s intriguing, because the water clearly sinks somewhere there, there are signs of a large whirlpool in high-water conditions, and the draft during summer must have come from somewhere. I don’t think this is a mystery that’s going to be solved with the water still there however.
About the photo
Despite the excitement happening at the end of the cave I elected not to take the camera through the roof sniff. The camera usually travels in a small orange pelican case for “dry” caving trips, and this trip I experimented with also wrapping it in cling wrap. By the time we reached the bottom the inside of the pelicase was a lot more damp than I was comfortable with. The photo above was taken earlier in the day as we progressed down through the boulder pile. It certainly contributed to the damp!
As you climb through the boulder pile in the higher reaches of the cave you criss-cross this stream several times. In this case Sandy was climbing back up after checking a hole off the original route. I was happy to get some action shots under the water. Unaccountably, Sandy was not keen on repositioning the off camera strobe in her hand or taking direction on poses. Her posture in the first shot here is completely natural and sums up her opinion of the artistic exercise.