How to go about connecting Fishface to SMK system

by Radost Waszkiewicz (8 March 2023)

My goals

Analysis of the current situation

CUCC expoers often refer to horizontal levels and connections between them when talking about exploration in Austria and many have played around with Survex/Aven trying to align (by eye) different cave-rich levels to get a better understanding of what's going on. I tried to quantify this method using the avaliable svx data with a particular emphasis on the Fishface area.

I have imported all the survey legs in 290 291 204 and 161, and produced a histogram of the directions in which these legs were shot. After eliminating short legs (less than 3m) and the vertical legs, you can plot them using an equal area projection (according to wikipedia apparently used also by some geologists). On such a histogram, the sphere containing all possible shot directions is mapped onto a disk of radius 2 with equator being mapped onto a circle of radius sqrt(2) -- marked on the figure, and since this is equal area projection, higher density means acually higher density in reality (and not just transformation artifacts).

Figure: Survey shot directions displayed using Lambert azimuthal equal-area projection. Dashed circles correspond to horizontal and vertical shots, while solid circle shows tilted cave-rich.

As expected, typical, non-vertical legs are roughly horizontal, but there is a systematic deviation from that horizontal pattern -- legs shot westward are more likely going down. The overrepresented directions line up on plane which, in this projection, is a near-circular loop. (Equations of great circles in this projections are surprisingly hard to find.) Additionally, I have marked normal direction to the plane of interest to make it easier to see how much and in what direction this plane is tilted.

The cave-rich plane is tilted down by 13.5° in the direction of 120° (roughly ESE). As a result, for each meter we travel in the approx eastward direction, we are expected to drop down by 24cm. With Fishface-SMK gap being at least 150m, this gives 35m elevation change.

To see working 3D plot, visit the original copy of this page at

3D Figure: Fishface+Happy butterfly in relation to 204 and 161 colored by levels. Note vertical shift in the levels due to east-west gap (at 15° slope we get 30cm up per meter distance). The proposed connection strategies are marked in red and pink respectively. 'Shallow' connection strategy lines up with light-green cave-rich level.

'Shallow' connection strategy

My proposed strategy is to continue from 290.whipingbalconysarse.27 (QMC 2.5mx1m) towards 204.midlevel.pretzelpassage2.31 for 300m at a gradient of 14.5°. or from 290.redlight.9 via QMB (3mx2m tube across a traverse) towards 204.midlevel.pretzelpassage2.31 280 meters away at a gradient of 16°.

290.whipingbalconysarse.27 looks like heading in the right direction and drafting in the Fishface direction (consistent with higher entrance of Balcon), albeit not a great lead by Rob Watson's description. Source: After setting up the cave link and failing to send/recieve anything we had a curry. Then Mike and I headed off to survey Balcony's arse while Luke and the Jape fettled the Cave Link. Got very muddy in the Arse only to break out at a junction, where we elected to look at the meander rather than the small tube higher up. Left a QMC pissing off upstream then back to camp for noodles. Schnapps and bed.

290.redlight.9 large phreas heading in the right direction in a area with good draft. Surveys further down mention no draft so it seems it has to dissapear (hopefully into that QM). Source: [...] but became too difficult to continue without a traverse line but promising [phreas] visable 50m further along.

204.midlevel.pretzelpassage2.31 great looking QMA with stones rumbling for 8 seconds. From the description (and drawing) starting with a large void. Not explored further because it was partly a derig trip and run out of time. Looking at the drawing it might go in the right direction (west). Source: This led along an attractive thick cracked mud floor to ... another large chamber with the sound of much water. We though this might well be the same chamber we'd encountered on our initial survey though when the data went in we were less convinced as the two ends were 43m apart but it is still plausible.

Deep connection alternative

Greedily searching for two points in respective systems underground that are closest together gives different potential connection endpoints with 204.deepsouth.razor11.13 near 204.deepsouth.razor12. This location is literally as deep as it gets -- it's a traverse over a pool of water with some QMs in the ceiling and is unlikely to be explored from this side. We might emerge here if we start from Fishface side but starting here seems unwise. Source: Andreas rigged a traverse where the slot began to widen + reached a stance overlooking a deep, dark pool of water.

Strategic considerations

The way I interpret CUCC expos mission, we should prioritize two things:

In my opinion, both of these are better served by pushing shallow leads and connecting Fishface to SMK as soon as possible. A few years ago, one of the targets was to search for a new 'east' surface camp to aid exploration in Homecoming, which is really quite far from the Stonebridge. One of the arguments for deep caving is that we'll have underground camp reducing crowds in the Stonebridge -- perhaps a better way to go about that is to have another surface camp near Fishface (or even better between Fishface and Homecoming)?


PS If the iframe does not work for you, here is a static snapshot: