TUNNELS AND MUD.

Auckland Star, Volume LXVII, Issue 238, 8 October 1936, Page 8

TUNNELS AND MUD.

AVONDALE SEWER. WORK 65FT UNDERGROUNC PROJECT WEUO AI>VANCEI In a tours t of enthusiasm this morn in two pressmen splashed their wa, through mud and slush into a tunne 65ft under the ground..' The Aucklan and Suburban Drainage Board is... a present engaged in. a sewerage scheme t connect the Avondale district with tli Mount Albert district, and the tunnel ii part of the work. The project wa •begun in May, and 16 expected to bi finished in March or April. In all, sonn 5000 ft of country have to be traversed and most of it : is such that tunnelling will be necessary. Some 100 ft of tunne has already been completed. The work is known as No. 9 brand of the Auckland main drainage. Th general route is from the grounds of th Auckland Mental Hospital, passin; along the bank of Oakley Creek, am running also roughly parallel wit! Blockhouse Bay , Road, and emergin; finally at Powell Street, Mount Albert where the sewerage from the distric will flow into this new system. One Particular Tunnel. The particular tunnel in which tin pressmen were interested entered thi face of a hill about half a mile from tin Mental Hospital boundary. Oaklei Creek tumbled a muddy way just nea; where the tunnel began. The oversee] in charge of the work, knowing thi nature of the underground, advised gun boots. These were accepted, and thi journey began. At the entrance th< "hole" in the side of the hill was sft liigl and 4ft wide. Gradually the heighl increases to oft, but the width does liol increase, so that every now and agaii one came unpleasantly into contact witl Wet and dank walls. . Further, sft is not a great height foi the average man, so that it was necessary to stumble along in the attitude of "every picture tells a story." Bui neither the walls nor the roof were tlx worst. It was the floor—if a tunnel has a floor. Then were the two pressmen glad that they had borrowed gum boots Every step was inches deep in slush so that the noise paramount in the bowels of the earth was one of loud squelching. The guide ahead carried a lamp, which showed just enough flickering light to enable the party to keep to the duck boards, and to prevent the members from tripping over the light railway lines, used to truck out the spoil. For 300 ft the men have eaten their way into the hill, and they have still 500 ft to go. They are at present 05ft below the level of the ground, and still boring. So far below ground there is an almost complete absence of sound. Everything k still, so still that the downward dripping of water seeping in sounds like a miniature explosion. How Air is Kept Fresh. Fresh air is guaranteed by a suction pump feeding into a pipe which advances with the tunnel. The used air is drawn out, while the fresh air flows in naturally. The nature of the country is such—solid papa rock—that timbering has not been necessary beyond the first 40ft. To the layman it seems astonishing that men with a pick can, apparently, keep on hacking at the tunnel end and yet keep the level mathematically correct. The overseer waved away the difficulties with a wave of his dilapidated and muddy hat. He went into details of engineering terms and blue prints, theodolities and pegs, until it seemed that all you have to do is to dig and the rest is bound to be right. There are 28 men altogether engaged 011 the work. The majority of these are either tunnelling or else taking away the spoil. Others are lifting earth from another part of the tunnel through manholes, or else repairing tools in workshops. From the road none of this work can be seen. You simply come abruptly to the lip of a narrow gully, and there the work is in progress. j