TO WIN GOLD

Southland Times, Issue 20010, 26 October 1926, Page 8

TO WIN GOLD

ROMANCE OF KAWARAU FINALISING WORK AT BIG DAM ADDITIONAL OPERATIONS PROBABLE Work at the Kawarau dam is all but completed and the passing of a few weeks will see the finishing touches added. The initial trial of the structure proved its complete efficacy from an engineering standpoint, and should equally successful results be forthcoming in the matter of the gold that is won from the river below it, there is every likelihood of further constructional operations being undertaken.

Since the first flush of excitement and enthusiasm at the closing of the Kawarau dam there has been little, if anything, to stimulate interest in matters concerning the most romantic mining proposition of the era. The gates of the dam have been submitted to a formal trial —with results entirely satisfactory from an engineering standpoint—and with the efficacy of the structure definitely established there has been nothing outside the finalising of a few minor details and cleaning-up operations generally to maintain interest. It is estimated that six weeks will see the finishing touches completed for all that remains to be done now is the construction lakewards of a protective wing wall on the north end and the laying of planking at both approaches to the bridge which has been constructed in conjunction with the dam. This completed activity will practically cease altogether until the commencement of the next mining season. Every week witnesses a diminution in the number of workmen engaged on the job. Seventeen hands were put off on Tuesday last, and whereas upwards of 100 men were employed when constructional operations were at their highest only 20 remain to-day to carry out the final processes, and this number will be further reduced as the seal of completion is set to the different phases of activity. To the layman, taking a comprehensive view of the structure from the adjacent banks, two features predominate—the enormity of the eleven,concrete piers which stud the locale of the erstwhile Kawarau Rapids and by comparison the extreme lightness and shallowness of the 10 gates which span the interstices. The bridge which has been thrown across the top of the piers suggests itself as the reason for what are apparently unnecessarily long mainstays. This, however, exercised little, if any influence on the innate character of the dam. Safety was the prime factor of determination in this respect as everything had to be done to ensure the utmost protection both for the structure itself and the property and life which would be endangered should it prove insecure enough to cope with the forces it was erected to control.

The comparative shallowness of the gates is explained by the fact that it was unnecessary to have them deeper than the height to which the waters of the lake can be dammed under the terms of the license granted. During, a normally dry and frosty winter the lake sinks to a minimum level, which has been noted and marked on the guage at the dam. When the gates are closed the level of the lake can be allowed to rise only six feet above this mark, at which point it reaches the top of the dam gates and consequently gains an escape through the usual channel of the Kawarau River. Should the waters be stored to a higher level the safety and well-being of Queenstown and the various settlements around the lakeside would be imperilled, and this has been the all-important consideration in determining the maximum permissible Lake Wakatipu boasts such an extensive area —approximately 112 square miles—that any rise occasioned by the closing of the dam would be almost imperceptible. In fact it is estimated that under normal conditions three • months would elapse before the six foot limit was reached, but the period of closing would, of course, be regulated by the weather conditions obtaining at the time. If a frosty, dry winter was experienced, for instance, the storage period would naturally be longer than if conditions inclined towards snow and rain. Under the terms of license granted to the Kawarau Goldmining Company pro ; vision has to be made for the outlet of storage water before the spring thaw sets in; otherwise there would arise the contingency of storage and thaw water raging through a channel totally inadequate to carry off such an enormously increased volume. A Board of Control, comprising representatives of the Queenstown Borough Council, Lake County Council, Clutha County Council, Clutha Drainage Board, Inchclutha Drainage Board and the Kawarau Goldmining Company, has been set up to determine when the gates should be closed and opened, and this body which will function under the chairmanship of Mr Marks, District Engineer, Dunedin, will be guided in its deliberations by the weather conditions ruling at the time. The mining season can be taken as commencing some time in May or early June and continuing until early or mid-September. The period, however, will be subject to considerable fluctuation and will be entirely dependent on climatic conditions. It has been suggested that in some years it might be possible to close the dam as early as February, but this would only be practicable' in a very hot, dry summer following on a winter which had been free from rain and snow.

The first mining season under the auspices of the Kawarau scheme is decreed to be one of exceptional moment and interest in that the suggestion to undertake further constructional operations will depend on the results achieved. This question, though possibly not looming large in the mind of the general public has not been lost sight of by those responsible for the erection of the present dam, and added interest therefore will attach to the first season’s operations. When the Kawarau scheme was first mooted it was associated with the subordinate proposal to build a dam in the upper reaches of the Shotover River, which empties into the Kawarau a few miles from its source. This project, however, involves the vexed question of additional finance and property rights, and. those in command have deemed it advisable to await the results of the first season’s working before arriving at a decision either for or against the suggestion. There is every reason to believe that when the gates are closed on the next occasion that the volume of water still remaining in the Kawarau will be much less than it was on the occasion of the formal trial, as at that period the Shotover was carrying about twice its normal volume. In view of this it is anticipated that claim-holders will have a much better opportunity of winning gold than the late trial might have indicated, in which case the matter of obtaining sufficient finance for the additional venture should not prove a deterrent. This prospective second phase of Wakatipu’s mining romance is characterised by an alternative to the original proposal in favour of damming the Shotover. If this were done a large body of water could be controlled, but if as suggested, the dam was constructed at the Branches a repetition of the present state of affaire as they exist in the Kawarau would be experienced in the Shotover—there would still be the water brought down by tributaries to contend with even though large areas of rich auriferous land were exposed. The alternative suggestion has therefore arisen that the Shotover should be left alone and that a further dam be built below its confluence with the Kawarau. This would force the waters of the Shotover back into the present storage area and render accessible a much greater area of the Kawarau River in its lower reaches. The Nevis and Arrow streams would still be draining into the main river-bed, but it is contended

these although subject to quick rising floods in the spring, do not constitute a particularly arduous problem. At the present juncture, of. course, both suggestions are entirely “in the air” and results will first have to be forthcoming from the present venture before one or the other assumes anything like definite proportions.