C—l 4

XX

Deposit of mining d6bris to lie restricted. Under the Proclamation it is permitted to place mining debris or mullock taken out of the mines in the river. So far as the Waihi and the Komata Reefs Mines are concerned, no harm will be done by the cancellation of the permission to cast such material into the watercourse, as there is ample land obtainable in the neighbourhood of the mines on which to stack such material; but in the case of the mines situated in the Karangahake Gorge there is no land available for such stacking, and stacking would consequently involve an excessive expenditure. The Commissioners therefore recommend that mining debris should only be permitted to be placed in positions from whence it might be carried into the River Ohinemuri under a special permit to be issued by the District Inspector of Mines, whose duty it would be, before issuing such a permit, to satisfy himself that the material cannot be otherwise economically disposed of. Komata Creek : Defiance of Proclamation. The Commission desires to draw attention to the fact that the Komata Creek has been used as a sludge-channel by the discharge into it of tailings and mining debris, notwithstanding that the Komata and Tarariki Creeks were specially exempted under the Proclamation of 1895. In this Proclamation the Komata Creek is described as a tributary of the Ohinemuri River, whereas it flows into the Lower Waihou, and it is understood that advantage has been taken of this erroneous description to avoid the exemption provided in the Proclamation. The Commission recommends that in the proposed new Proclamation the use of the Komata Creek as a sludge-channel should be restricted to the company now discharging its tailings therein, and that the same degree of fine grinding should be required as for tailings to be discharged into the Ohinemuri. Repeal of Proclamation. The Commissioners therefore recommend that the Proclamation making the Waihou and its tributaries, other than the Ohinemuri and Komata, a watercourse for the reception of mining debris, tailings, and slimes, should be repealed, except in so far as existing mines are now using them; that if any other mines in its watershed should desire to utilize the river or its tributaries, permission be specially given, after careful investigation and on special conditions, particularly as to fine grinding. Stop-banks. —Flood-gates. The Commission recommends that wherever the river-banks of the Lower and Upper Waihou as far as Te Aroha, and the river-banks of the Lower Ohinemuri and of all tributary creeks to those rivers, are at any point below a level of 4 feet above the level of the highest-known flood, then there should be made artificiaf stop-banks having a crest-level of not less than 4 feet above that of such highest-known flood. These stop-banks should be of approved design, not less than 6 feet wide on the top, placed with the land face on an average not less than 95 feet back from the river-banks as existing prior to the pinching of the widths due to the deposits of tailings. These stop-banks must be constructed with proper culverts, fitted with flood-gates of an approved design, so as to let all land-drains empty into the rivers except in times of flood. The stop-banks are to be formed of dredgings taken from the bed and banks of the adjacent channels, which channels will be thereby much improved. Dredging. It is recommended that suction dredges should be employed in making these stop-banks and in deepening the rivers, the land side of the banks being formed of manuka brushwork in such a manner as to protect the lands from damage during the construction. The banks must be fenced off on the landward side, «o as to protect them from cattle. All cross fences on the river side should be removed, and all willows and other trees on the river side of the banks should be cut down and destroyed.