D.—l.

On the Waiau-Tikiwhata Tunnel (south end) excavation and lining has been in progress throughout the year, with the exception of the periods in February and April previously referred to. A length of 11-J ch. has been excavated and timbered to full section. The portal is complete and lining carried over 7 ch., stub walls and footings having been constructed for a further 3-J ch. Mucking scraper and loader, concrete-pump, and steel profiling are in use in this tunnel. During the year the installation of 800-cubic-feet Diesel compressor unit, 25-h.p. ventilating-fan, bins and batch ing-plant, and track lay-out inside and outside of tunnel were completed. The clearing of approach cuttings to tunnels at 30 m. 47 ch., and 31 m. 40 ch. was in hand in February. Since then it has not been possible to proceed with work owing to the man-power concerned being diverted to the access road. Maintenance of the service road form the Kopuawhara Road bridge to the south end of the Waiau-Tikiwhata tunnel, a distance of 9| m., has been carried out, and the metalling of the Coast Road to over a length of 4 m. completed. Very considerable damage occurred to the road during both the February and April floods, and although it should be open for traffic to the Waiau-Tikiwhata tunnel within a month considerable surface trimming and metalling will be required. The crushing-plant previously installed in the vicinity of 33 m. has been put into operation at Kopuawhara at 29 m. 40 ch. The two road bridges opposite 30 m. 65 ch. and 31 m. 25 ch. which were destroyed by the February flood will very shortly be replaced. In the meantime the stream can be crossed by fords. Service repairs were carried out to accommodation, porches to married quarters were added where required, and single-men's tents provided with lining. Inspection and maintenance of the main 11 kV. line and reticulation was carried out and a voltage regulator installed at Opoutama. Considerable renewals of the main line were necessary in February after the flood, when approximately a mile of new line was erected. Wharerata Section (Length 9 m. 17 ch.) —Tunnelling and heavy earthworks constitute the major problems on this section. The earthworks are nearing completion, and the tunnels are being vigorously attacked with the help of up-to-date machinery. With the exception of the smaller culverts on the section between 19 m. and 20 m. 36 ch. and in the Tikiwhata Valley, culverting is completed. These smaller culverts will be constructed when the completion of the formation provides cheaper access. 63 ft. of pipes up to 24 in. diameter were placed during the year. At 19 m. 71 ch. a 5 ft. by 4 ft. drive was excavated in order to divert a small stream to a suitable culvert site. Earthworks on this section are nearing completion. In the Waikoura Valley the embankment between 16 m. 5 ch. and 16 m. 30 ch. has still to be formed with spoil from the Waikoura Tunnel at 17 m. 51 ch. Between 14 in. 50 ch. and 15m. 18 ch. minor cuttings will not be started until bridge-work in the vicinity is further advanced. Major cuttings between 18 m. 43 ch. and 20 m. 36 ch., the section along the sea-coast, are completed except for trimming batters and the removal of slips. In the Tikiwhata Valley the big filling at 35 m. 62 ch., 105 ft. high, is gradually taking shape. The rock cutting between 35 m. 70 ch. and 35 m. 76 ch., together with 356 lineal feet of concrete retaining-wall, has still to be completed. Two f-cubic-yard Diesel excavators were employed on the section, the total earthwork completed amounting to 470,250 cubic yards, or approximately 94 per cent, of the total. The contractor has started on the construction of a new highway bridge over the Maraetaha Stream at 15 m. 15 ch. This bridge will improve the road-alignment and eliminate a railway overbridge. Hie use of modern machinery in the larger tunnels has enabled the work to proceed more rapidly and has reduced to a minimum the heavy manual labour previously associated with such work. Electrically operated muck-scrapers load up to 95 per cent, of the spoil into trucks without handling. The difficulty of exchanging full for empty trucks at the loading-slide is overcome by using a compressedair hoist to lift the empty trucks clear and lower them at the rear of the rake of trucks hauled by an electric locomotive. A rake of eight or ten trucks can be filled in this way on a single track, no siding being required. Concrete for lining the tunnel is placed in position behind steel profiling by means of an electrically driven pump. In a period of ten to twelve hours 32 ft. of tunnel can be lined in one operation. The Waikoura Tunnel (1,576§ lineal yards) (north end) having the easiest access, is the furthest advanced, and various methods and positions for the machinery were tried here before adoption in the other major tunnels. Work was delayed by floods, a large slip occurring on the spur above the bins and concretemixing plant. The structure was moved on its foundations, and although the bins have been secured the structure housing the mixing-plant had to be rebuilt on a new site. To date 420 lineal yards of tunnel have been excavated, 244 lineal yards lined with concrete, and an additional 30 lineal yards of concrete butt walls placed.' At the Waikoura Tunnel (south end) the same methods are adopted in this face of the tunnel as at the north end, and good progress has been made. 272 lineal yards of tunnel have been excavated, of which 110 lineal yards are lined with concrete. A further 81 lineal yards of butt walls have been placed ahead of the completed lining. At the tunnel at 18 m. 70 ch. (101. lineal yards), 29 lineal yards were excavated and 34 lineal yards lined with concrete, completing this tunnel. At the tunnel at 20 m. 10 ch. (131 lineal yards), 55 yards have been completed, including lining, and a further 14 yards of top heading driven. Progress has not been rapid owing to the heavy nature

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