7

H.—9

Wholly confined to the two former : the totara round legs in almost every instance are considerably decayed; the kawhaka seems to stand a little better than the totara, but where nails and bolts go. through it the wood is in a decayed state, and in some instances the heads of the nails can be, with ease, drawn through the timber. The silver pine and rata trestles are as sound as on the day they were constructed. This shows that, wherever the two latter kinds of timber can be obtained at a moderate cost, they are the most economical to use. The other bridges and flumes along the line of race appear to be in fair condition. Kumaea.—This field is confined entirely to hydraulic sluicing, and is worked by water from the Kumara Water-race and the Okuku Company's race. The Kumara Water-race was originally commenced by a private company, but was purchased by Government in 1877, who completed its construction, and afterwards enlarged its dimensions, in order to bring a larger supply of water on to the field. Recently a reservoir has been constructed in the Kapitia Valley above the loop-line road to store water, so that the supply can be kept up in dry weather. It is capable of supplying 100 heads of water for twelve hours per day for about three weeks, but in very dry weather the supply of waiter available is not equal to the present demand. The cost of this water-race up to the present time has been about £37,367 4s. In conjunction with this water-race the Government constructed the Kumara Sludge-channel as a tail-race, to enable a large area of flat ground to be worked: it was. originally 85 chains in length, constructed in a tunnel. The lower 40 chains of it is 10ft. wide and sft. high above the top of the channel, and the upper 45 chains 7ft. wide and the same height. But since the workings commenced the tailings from the channel have filled up a large valley between the mouth of the tunnel and tho Teremakau River to such an extent that the boxing of the channel has been carried out for a further distance of about 30 chains, and very soon will bo at the edge of the Teremakau River. Tho cost of constructing this sludge-channel up to the present time has been £17,200 12s. 6d. The cost of maintaining the channel has been very heavy, and has far exceeded all estimates that were ever made. It was originally paved with wooden blocks set on end, Bin. deep; but the cost of replacing them was so great that stone paving was tried, and in order to' get paving of a greater depth the sides of the channel have been raised, and 14-in. pavmg-stones used. About 2 chains of cast-iron blocks have likewise been used, and the result of tho cost of the different classes of paving, from careful observations of the manager during the last twelve months for the lower 70 chains of the channel, where the wear and tear are the greatest (m tho upper portion of the channel the wear is not nearly so great), is shown in the followingtable :— °

The last item is calculated on the basis that cast-iron blocks are to be of hematite iron, and can be placed in position in the chaunel at £16 per ton, which would probably be done at this rate for a largo quantity. The cast-iron blocks at present in use cost about £18 10s. per ton. The above table shows the cost of stone paving to be much less than any other. The cost of different-classes of paving has been taken in the channel near the mouth of the tunnel; therefore the wear is all under the same conditions. The stone paving no doubt reduces the carrying capacity of the channel to some extent; but the manager, who has had every opportunity of making careful observations, states that the difference in the carrying capacity of the channel between the stone and wood paving would be not more than one party each shift, and, as there are three shifts working in the channel, and seven parties each shift, if it were wholly paved with wooden blocks, instead of accommodating twenty-one parties each day, it would enable twenty-four parties to work. Therefore, taking this as the basis to work on, the total revenue derived from parties using the channel last year amounted to £2,128185. 3d.; and, if one-eighth more parties had been able to use it, the revenue would have been increased by £266 2s. 3d., and the wear and tear of the blocks would also be increased in equal proportion. The cost of maintenance for the year was £6,405105. Bd.: this would be increased by £800 13s. 10d., showing a still greater loss on working. However, the water-race and sjudge-channel have to be taken together, and the conjoint result of the workings shows a profit of £1,886 17s. Id., or nearly 3-| per cent, on the capital invested, the total cost of construction being £54,564. 16s. 6d. This field will take a number of years to work out, but the limited space that there is for tailings will soon become a question that will demand attention, as they will be carried into the Teremakau River, and will gradually fill up its bed, and cause the flood-water to damage tho property along its banks, for which compensation will no doubt be required. Humphrey's Gully. —There are large works in course of construction here to enable the whole of the drift terraces in the neighbourhood to be sluiced away in a wholesale manner into the valley of the Arahura River. These works are being constructed by the Humphrey's Gully Company, which is formed with a capital of £150,000. They have constructed an open ditch for a distance of about five miles, capable of carrying about one hundred heads of water, and near Milltown there is about three-quarters of a mile in length of a ponderous aqueduct, which resembles more a canal than a water-race, very substantially constructed; and they are at the present time constructing a reservoir to store water, and tunnelling through the range to get the water on to the mining leases. When these works arc complete, and a tail-race constructed, a commencement will be made to work their

Class of Paving. Cost per Chain placed in Position. Number of Weeks that Paving lasts. Cost per Woek per Chain of Paving. Cost per Annum for Maintaining tho Pavement in lowor 70 Chains-of Channel. Wooden blocks 14in. deep Stone blocks 14in. deep Iron blocks 3in. deep £ s. 14 10 38 10 184 16 d. 0 0 0 7 34 91 £ s. d. 2 15 1 2 10 2 0 7 £ s. d. 7540 0 0 4121 15 4 7392 0 0