GLORY HOLE CAVE, YARRANGOBILLY : AUSTRALIA'S FIRST SELF-GUIDED CAVE
BRIEF HISTORY
The Glory Hole Cave, Y-24, is the original "Yarrangobilly Cave" and is thought to have been discovered in 1834 by John Bowman, a local stockman (Smith 1969), though Trickett (1905) makes a more conservative claim for T.A. Murray in 1839.
The caves' first official caretaker, James Murray, was appointed in 1887, though he had been showing visitors through them for some time before his official appointment (Anderson 1887; Wood 1888).
The cave was open for public inspection virtually without a break until 1966, when the whole area was closed to the public for "renovations" (Anon. 1970). The electric wiring (installed between 1926 and 1929) had become unsafe and many sections of pathway required attention. As prison labour was to be used for much of the work, it was considered desirable that the area be completely closed to the public (the prisoners are still there, despite the fact that the area was reopened five years ago).
The Jersey and Jillabenan Caves were reopened in December 1968 but the Glory Hole Cave was not shown again on a regular basis until March 1970. During this time the paths were completely rewired, new pathways were built and a tunnel was dug into the back of the Glory Hole Cave.
THE CONCEPT
The idea of a self-guided cave was conceived by members of the Kosciusko National Park staff in 1968.
It appears that two very practical problems prompted the idea:
- That of enabling the caves to handle an ever-increasing number of visitors without extra staff, and
- That of ensuring that visitors would be able to see at least one cave if they were short of time or arrived after the normal tours were booked out.
Such a facility also has the advantage of allowing the visitor to proceed at his own pace, pause where he finds something of interest and take photographs at will. It was nevertheless, realised from the outset that such unsupervised inspections posed major problems for conservation and interpretation.
Although the plan received approval from Park and Service authorities in 1969, it has only been implemented gradually and is not expected to be completed until the end of 1973. A number of staff and outside contractors have been involved but the person principally responsible for the project has been Spencer Smith-White, Senior Interpretation Officer of the National Parks and Wildlife Service. The author was also heavily involved with the project in 1970 and 1971 when he was an Interpretation Officer with the Service.
THE CAVE
The Glory Hole Cave is the largest open for inspection at Yarrangobilly, having a length exceeding 300 metres served by a pathway over 500 metres (0.3 mile) long (Anon. 1971). The chambers are of large overall dimensions, e.g. Glory Hole Cavern (40m x 70m x 30m high), "Ice Age" (25m x 30m 10m high) and the Grand Dome (25m x 40m 50m high). It was once clearly once an outflow cave (possibly an underground course of Rules Creek - Anon. 1970), though it no longer contains an active stream. Even the lake in the "Ice Age" section now has to be kept full artificially, although it is adjacent to the depositionally most active section of the cave.
THE TUNNEL
The fact that the innermost section of the Glory Hole Cave was close to the cliffs on the western side of the valley of Rules Creek was known to surveyor Oliver Trickett before the turn of the century (see plan in Trickett 1905) and, according to the late A.H.M. Bradley, Trickett had spoken of the advantages of a tunnel from the back of the cave (Middleton 1972).
The tunnel was again seriously considered in 1967, as a means of increasing the number of people who could visit the cave, and in October of that year the Sydney Speleological Society was called in to carry out a detailed survey of the proposed site with radio-direction equipment and determine the best location (Halbert 1967).
The tunnel was not actually constructed, however, until 1969, when it was clear that it would be essential to have through' trips if the cave was to be operated on a self-guided basis. The cost of the labour involved was, of course, minimised by use of prisoners and the happy coincidence that one of their warders had had experience with blasting. The first (guided) tourist party came out through the tunnel of New Year's Day 1970 (Middleton 1970).
The author has proposed that the tunnel be called "Nangwarry Cut", from an aboriginal word supposedly meaning "path to the cave" (Middleton 1973). Its portal has been numbered Y-70.
DEVELOPMENT OF THE CAVE
Until 1966 the pathway through the cave was virtually 'natural', with little more improvement than some repositioning of rocks and a small amount of excavation (particularly in the only constricted section, known as the Blowhole). The lighting, too, was functional rather than aesthetic, with bare bulbs (110 volts), occasionally shielded, on metal stands.
During the redevelopment the pathway was completely reconstructed in concrete (apart from the "Ice Age" - Blowhole section, where steps were cut in flowstone) and lined with steel pipe handrails and "Cyclone" wire. Three sets of steel steps were constructed for a steep section at the lower end of the tunnel. This work was carried out almost completely by prison labour, under the supervision of warders and generally with little direct control by the Park authorities.
The cave was completely rewired for 240 volt lighting and all the original lead sheathed wiring (with the exception of one pair of lights which the author managed to save as an historical exhibit) was removed. It was subsequently realised that 240 volt lighting was too dangerous in such damp conditions and the cave had to be again rewired to enable a 110 volt supply to again be used. Since, as a self-guided cave it would be necessary for all lights to be on all the time, it was considered desirable to use high efficiency lighting where possible. Four quartz-iodide lamps have accordingly been installed, but because of their high light output their use is restricted to locations where large areas can be lit from a single source. Proposed fluorescent lighting in the "Ice Age" section (where it was felt its 'hard' white light would enhance the stark whiteness of the decoration as well as save on power) has not been installed. The path has been lit independently of the floodlighting with tracklights at regular intervals.
The author raised the question of emergency lighting in 1970, particularly as there might not be a ranger present if and when the lights failed. A system of automatic emergency battery lighting has since been installed.
PROTECTION OF THE CAVE
The cave operator's first duty is to protect his caves from vandalism and this must be recognised as a major problem if parties are to be allowed to inspect a cave unaccompanied. The Glory Hole Cave, because of its relatively large proportions and the massiveness of much of its formation, is unusually well suited for this type of development. Rarely is the roof height less than four metres and the path is nowhere within reaching distance of delicate formation. As mentioned, the path is well fenced, so there can be no ambiguity as to where the public may go. Besides this all visitors are given verbal and written warnings not to leave the path, and of the physical and legal dangers of doing so.
Despite these safeguards and precautions it is considered desirable to have a ranger on duty in the cave at all times, though this is not always possible in practice.
The plan calls for the construction of a turnstile in a fence at the back of the entrance chamber, to be activated by tokens purchased at the Visitor Centre. Construction of this has been delayed by aesthetic considerations but it is expected to be in operation by the end of the year. In 1971 a plan was prepared for a high wooden palisade right across the Glory Arch but this has been rejected.
"Nangawarry Cut" was pushed through, in part, along a natural fissure but this has, as a result, been opened up to many times its original size and a strong draft is always evident in it. Despite the author's best efforts, no door (such as those on the Binoomea Cut) has ever been installed to control this draught (those opposed to sealing the tunnel point out that there was a natural fissure there and that there are at least two other major natural holes in this section of the cave). Apart from the door, a turnstile is required to control access through the tunnel.
Since April 1971, when the Park Engineer, realising that the roof above the Grand Dome was not very thick and appeared to include a number of wedged boulders, raised the question of its safety, this interesting section of the cave has now been closed off. This section includes two of the recorded commentaries, some of the finest formations in the cave and a quite spectacular high dome roof. If there is any danger of the roof collapsing it must surely be heightened by the continuing passage of cars and occasionally tour buses along the road which almost passes over it — yet the cave has been closed rather than the road.
INTERPRETATION FACILITIES
It was originally intended that, in the absence of a guide, information about the cave would be made available in the form of a detailed brochure. The great drawback to this is the difficulty of reading in the cave, where lighting may not always be adequate. To overcome this it was decided to provide tape recorded commentaries. Seven of these are located at points through the cave; the tape players are activated by visitors pressing buttons at each of seven platforms. In addition a small brochure is provided, giving some background information and a plan of the cave (Anon. 1971).
As a further aid to interpretation it is intended that there should be a limited number of illuminated signs at points of interest throughout the cave which do not justify tapes. A major display in the Glory Hole Cavern, just inside the entrance, would explain the nature of limestone and the mode of formation of the cave. This part of the project has not yet been completed, though the cave has been operated on a self-guided basis since April 1971.
It is also intended that the ranger on duty in the cave should be available to answer visitor's questions, as well as being on the lookout for acts of vandalism.
The project has not all been plain sailing; there are problems intrinsic in the method, there have been problems with the equipment (discussed in the following section) and there is a minor problem relating to planning. Whether parties are guided or self-guided it is necessary for people to come together at some points where items of interest can be explained. In the case of Glory Hole Cave the platforms for this purpose were located long before the interpretation of the cave was planned; presumably they were located where the path builders found it convenient, perhaps with some guidance from the locations at which guides had traditionally paused. In most cases this has not proved to be a difficult problem, particularly if a guide is present. Poor location became a much more difficult problem when compounded by the limitations of tape recordings.
Perhaps the major intrinsic difficulty with a tape recording is one's inability to point out things; references to right and left are of no help as one cannot be sure in what direction people will be looking at the time. Descriptions must thus concentrate on very obvious features (such as a brightly coloured piece of flowstone) or make generalisations (as about stalagmites in an area where these are prolific). References to items which are to be seen from one platform and the next must be kept to a minimum as there is no opportunity to point these out along the way. One method of "pointing" which could largely overcome these problems would be control of spotlights by the tape; an idea which is technically feasible but probably beyond the financial resources of Australian cave developers.
Acoustics can prove a problem as two or more tapes running simultaneously in different parts of the cave may interfere with each other. The extent of this problem depends on platform location, cave configuration and acoustics, speaker location and volume. Since platform location is generally determined by the existence of items of interest (if not by the convenience of path construction) it will usually be necessary (as was the case in parts of the Glory Hole) to find the optimum speaker locations and volumes by trial and error, particularly in the case of the last three commentary points which are located in the same chamber.
THE AUDIO EQUIPMENT
In an effort to ensure the best possible results from the audio equipment, consulting audio engineers were sought to advise and quote on the Glory Hole Cave installation. In due course Amalgamated Wireless of Australasia was given the contract.
The tape players (there is no point in their having any recording capability) used are "Tandberg", model 1342 (highly modified) which were especially imported from Norway. A number of similar machines are already used by the National Parks and Wildlife Service for continuous audiovisual presentations. These players take a standard continuous cartridge which can take a commentary up to two hours in length, although the average length of the Glory Hole commentaries is only about two minutes. These machines are fitted with a remote start facility and can be automatically stopped by a piece of conducting tape affixed to the tape at the end of the message. Model 1342 had to be modified (twice) so that it did not reject the cartridge at the end of the message and so that the remote start could not be used to stop the machine part way through. Machines are now available which would not require these modifications.
For reasons of security, surveillance and dampness the tape players are located in the Visitor Centre remote from the cave. This required the undergrounding of seven pairs of control wires and seven pairs of speaker leads some 250m to the cave and then up to 300m through the cave itself.
The speakers used are TCM5K re-entrant horns which were recommended for the continually damp conditions in the cave. These will not reproduce music very satisfactorily but are quite adequate for the human voice. They have operated very well, even when partly or wholly filled with water.
Problems have arisen with location of the speakers: it is preferable that these be not obvious to the visitor, yet they should point directly at him; it is preferable that they should lie on the ground, yet they cannot be pointed upwards or they fill with water (by condensation, if not directly from drips); as mentioned, they should also be so positioned and operated at such a volume as not to overlap others operating simultaneously elsewhere in the cave. These problems have not yet been entirely overcome and trials are now taking place with some speakers placed on posts.
The cost of the installation was $4,950. To this must be added $1,600 for the seven tape players plus a couple of hundred for sundries. The total cost (except labour) would have been about $5,500 to $6,000.
There are now no difficulties with the playback equipment itself. Tapes can easily be revised and changed, spares can be held in case of tape failure and there is a spare machine which can readily be substituted in case of mechanical breakdown.
SUMMARY
The Glory Hole Cave has been developed as a self-guided cave by provision of:
- a tunnel to make a through trip possible,
- a stable, if uninspiring, rigidly fenced pathway,
- tape recorded commentaries at seven (now five) points through the cave
- an explanatory brochure.
The project is at present, however, deficient with respect to:
- interpretive displays and signs which have not yet been installed,
- a gate and turnstile to control entry and
- a door and turnstile to control draught and entry through the exit tunnel
The development provides the visitor with the advantages of:
- not having to wait for a scheduled inspection,
- a greatly reduced chance of being turned away altogether during busy periods
- being able to inspect a cave at his own pace and
- less distance to walk (due to the tunnel rather than the self-guided facility itself).
The development has been of benefit to the administration by:
- providing for an increased number of visitors without a corresponding increase in staff,
- reducing the number of dissatisfied visitors, though it has the disadvantages of:
- its capital cost
- increased power consumption because of the need for continuous lighting.
At the same time it is deleterious to the cave in that it carried with it increased risk of vandalism and it has the disadvantage for the visitor of depriving him of the personal services of the Ranger.
Problems with the audio installation have been related to:
- operation of the tape players, requiring modification,
- speakers filling with water,
- acoustic overlaps between speakers
- difficulties of pointing out particular objects in a tape recording.
CONCLUSION
The Glory Hole Cave is operating successfully as a self-guided cave, despite some acoustic problems and the lack of signs necessary to complete the interpretive programme. There is not yet proper control of access.
Similar equipment could probably be installed in any cave but the cave's physical suitability for this type of development (including the control of visitor access) must be a primary consideration.
It is the author's opinion that on balance, despite some shortcomings, the development has been beneficial both to the Park's visitors and its administration. A study of this programme is in the course of preparation within the National Parks and Wildlife Service.
REFERENCES
ANDERSON, W. 1887. Report on the Yarrangobilly Caves. An. Rep. Dept Mines NSW, 1886:165
ANON. 1970. Yarrangobilly Caves: Kosciusko National Park (National Parks and Wildlife Service: Sydney) 16pp.
ANON. 1971. Glory Hole Cave Self-guided Inspection (NPWS brochure) 6pp.
HALBERT, E. 1967. Yarrangobilly. Stop Press, 11(11):172
MIDDLETON, G. 1970. Current Developments in Interpretation at Yarrangobilly Caves. J. Syd. Speleol. Soc., 14(11):259-262
MIDDLETON, G. 1972. Obituary - A.H.M. Bradley. J. Syd. Speleol. Soc., 16(6):158-161
MIDDLETON, G. 1973. Clarification of Some Cave Names at Yarrangobilly. J. Syd. Speleol. Soc., 17(9):253-256
SMITH, R. 1969.History of Yarrangobilly Caves. (Kosciusko National Park: Cooma) (duplicated) 5pp.
TRICKETT, O. 1905. Guide to Yarrangobilly Caves (Geological Survey of NSW: Sydney) 1st Edn, 30 pp
WOOD, H. 1888.Annual Report by Under Secretary of Mines. An. Rep. Dept Mines NSW, 1887:9