THE RE-DEVELOPMENT OF TANTANOOLA CAVE
INTRODUCTION
The Tantanoola Caves Conservation Park is located in the Lower South East of South Australia on the Princes Highway between Mt Gambier and Millicent.
Tantanoola tourist cave was discovered by Boyce Lane on the 26th March, 1930 while using a ferret for rabbiting. Recognising the value of the Cave the entrance was opened, rough tracks prepared within 48 hours to enable the cave to be viewed by the general public by kerosene lamp on 28th March, 1930.
Tantanoola tourist cave and some 14 hectares surrounding it was dedicated as a Conservation Park under the National Parks and Wildlife Act on the 4th July, 1972. Since that time the tourist cave has been managed, under lease, by the District Council of Millicent.
THE CAVE
The cave is located in a stranded coastal cliff, which in itself is an important geological feature. The cliff is comprised of dolomitised bryozoal limestones and marls of the Miocene.
The cave is a single elliptical chamber approximately 25m x 18m x 8m containing a magnificent array of formations, the majority of which decorate the ceiling.
While not created by marine action the cave exhibits abundant evidence of marine transgression in the form of well rounded flint pebbles, sands, grits and the remains of coastal marine animals such as penguins and seals.
VISITATION
Up to 38,000 people visit the cave each year. This relatively large number is due in some part, to the caves location about 300 metres off a principal highway.
RE-DEVELOPMENT
In 1980 the National Parks and Wildlife Service commissioned the Australian Speleological Federation to formulate a management plan for the whole of Tantanoola Caves Conservation Park.
The management team, led by Mr Elery Hamilton-Smith, developed a plan of management which embodied a suggestion put forward by the cave manager Mr John Callaghan, "to construct the tracks in such a way that access could be gained to disabled persons". This suggestion became the hinge pin for the redevelopment.
Apart from access for the disabled, which would involve the levelling of pathways to a maximum gradient of 1:12, the management plan recommended:
- The excavation and widening of the entrance.
- Rewiring, and illumination of formation in keeping with currently accepted standards of presentation.
- Cleaning
RE-DEVELOPMENT
Re-development commenced on the 15th June, 1982 funded by a National Parks and Wildlife Service loan fund of up to $71,000.
Due to the confined working space it was decided to employ only one temporary maintenance worker to assist John Callaghan, as a consequence Jim Williams, a local man, was employed. The work was supervised on a day to day basis by the Senior Ranger, South East Region, Mr Peter Tomlin.
STEP 1 EXCAVATIONS
In order to achieve a lower entrance level and create sufficient space to park a small bus, it was necessary to excavate the talus slope which, while developing, had sealed the cave entrance.
Upon commencement of excavation it was discovered, much to our horror that the talus was not comprised of relatively small manageable rock material as anticipated, but of massive dolomite boulders fused to a solid mass by secondary cementation
Due to close proximity of the cave and kiosk, blasting was considered out of the question. The problem was eventually solved by the management of a nearby A.C.I. Dolomite quarry from whom we hired, at a peppercorn rental, a hydraulically operated "rock-popper" which facilitated slow but sure progress (a device which when placed in a previously drilled hole can be expanded hydraulically to exert sufficient pressure to crack the rock outwards).
The cave was eventually opened up to a level approximately 2.6m below floor level of the original doorway.
In the meantime the Melbourne based firm of Gutteridge, Haskin, and Davey had been engaged to determine a suitable array of illuminations that would highlight the cave's outstanding features in a pre-determined sequence, and develop a specification for wiring and switching. The engineer responsible was Mr Miles Pearce who was also a member of the original management planning team.
STEP 2 LEVELLING
Once the entrance had been lowered the pathways were marked out and graded to a maximum of 1:12. Much to our pleasure it was discovered that virtually the whole of the chamber could be made available to persons in wheelchairs.
A layer of dolomite dust from the quarry next door was then laid over the pathways to a depth of 3-4cm. This not only made a good base on which to lay concrete, but also a suitable material in which to place all of the electrical conduits which were to be buried below the pathways.
STEP 3 ELECTRICAL
From the outset it was very clear that anyone employed on this project had to have some feeling and consideration for the cave. We were extremely fortunate in our choice of electrician John Tremelling of John Tremelling Electrical who approached the contract with great interest and sympathy.
As previously stated all electrical conduits were placed under the pathways. In all about 1,000m of conduit were laid and about 3,000m of grey flex was attached to 3 major junction boxes and 4 switching stations.
Progressive switching offers 4 major scenes illuminated by 42 100W spots and 5 500W quartz lights.
STEP 4 CONCRETE
342m2 of reinforced concrete has been poured to form pathways within the cave, the vehicle approach ramp and small bus parking area. A dye was introduced to the concrete resulting in a colour which is now compatible with the general surroundings.
Concrete laying, of necessity, interrupted the electrical work which is another good reason to have an electrician who is "on-side".
It is worthwhile noting that great care should be taken to search out and remove concrete over-spill and splashes before they set.
STEP 5 FINISHING TOUCHES
At this stage it is difficult to relate the myriad of relatively small tasks which had to be undertaken before the cave development could be considered complete, sufficient to say that most of these tasks were aimed at blending, as far as possible, the introduced materials into the cave environment.
STEP 6 CLEANING
The big clean down. The first thing was to wash off all the collected dust and dirt accumulated during the course of re-development, this was simply a matter of hosing down. Algal growth as well as the collected lint and dust of fifty years of visitation became another story. To remove this we used high pressure water spray delivered at 750 p.s.i., mild acid solutions and chlorine based bleaches. The process was effective and the results pleasing.
STEP 7 THE DOOR
Last came the new door. We chose a B & D Roll-a-Door which is electronically controlled from a small hand-set to be carried by the guide. This effectively gets over the problem of a guide having to lead a group to the door, closing it after they have all passed through and then having to squeeze past to regain the lead once more. Leading the group at all times facilitates greater control while improving the level of visitor to guide communication.
STEP 8 LANDSCAPING
Outside the cave raw ground left by the excavations has been landscaped and covered with pine bark to await the autumn planting of some 2,000 seedlings which are being propagated at the Black Hill Conservation Park nursery.
STEP 9 A TRIAL RUN
Now that the work had been completed to our satisfaction there was only one question to be answered, did it work.
To discover this we asked a local quadriplegic, Jacqueline (Jackie) Chant of Tantanoola if she would assist us with a test run. She accepted and you can imagine our feelings as we watched Jackie negotiate the tracks without assistance in her motorised wheelchair.
The cave was opened for public viewing on the 17th January, 1983 seven months and one day after closure.
THE FUTURE
Apart from the seedlings to be planted this autumn, there are two other steps in hand.
(1) The power supply is to be placed underground. This will eliminate three unsightly stobie poles which supply overhead power from the H.T. line on the highway about 300m away.
(2) New toilet facilities will be constructed in a less conspicuous site and will of course include provision for disabled persons. The site of the old toilet block will then be utilised as a small car-park for the disabled.
Now that the cave re-development has been completed some errors have been discovered. Fortunately these are small and will be easily corrected.