BIG COLLIERY SCHEME.

New Zealand Herald, Volume LXIV, Issue 19720, 20 August 1927, Page 15

BIG COLLIERY SCHEME.

PEER'S MILLION POUNDS.

EXTENSIONS IN DURHAM. A REPLY TO SOCIALISTS. An interesting account of a great colliery project that is being carried out by the Marquess of Londonderry at an estimated cost of £1,000.000 is given in an article that he has contributed to a London paper. He savs: —" This development is flue. in which I take ail the risk. If it fails, the loss will be mine; if it succeeds, as I believe it will, the community and the State will benefit."

It is to the north of Seaham Harbour, between Seaham Hall and the town of Seaham, Durham, that the operations in connection with the new scheme were begun in 1923, and it is expected that coal will be reached by the end of this year. It will be a few years before the colliery is in full working operation. It will then provide employment for upwards of 3000 men, and it is calculated that it will produce something like a million tons of coal a year. The new colliery consists of two shafts which have been sunk to gain access to an area of coal which lies partly under the sea. Situated on the cliffs some 350 yards from the shore, the shafts traverse six well-known Durham 'coal seams which occur at depths of between .500 and 700 yards. The Maudlin and Hutton seams, which are situated at 574 and 618 yards respectively from the surface, have already been worked to some extent from the Seaham Colliery, but were abandoned some years ago on account of the distance the coal had to be hauled underground.

Bofh the new shafts have a finished diameter of 21 feet, and, as they had to be sunk through heavily-watered ground, a special process was necessary. Previous experience in this vicinity had shown that the magnesian limestone here contained large fissures, which in this instance were proved by a preliminary borehole to be in direct communication with the sea. Moreover, a very difficult waterbearing stratum of rock, known as the Yellow Sands, was disclosed in this bore hole, through which it was impossible to sink by ordinary methods. Consequently it was decided to freeze this water-bearing stratum overlying the coal measures and thus sink the shaft in a column of ice, as it were, in order to hold the water back until a suitable lining could be inserted. Freezing the Strata.

For the purpose of freezing the strata, thirty-three boreholes, spaced at regular intervals, were sunk around each pit, and pipes were inserted through which a freezing mixture was circulated by means of pumps, a smaller tube in the centre of the outer tube being introduced to carry 'the mixture to the bottom of the holes. The circulating mixture was cooled by evaporating liquid ammonia, for which purpose three steam-driven refrigerating sets were installed. This enabled heat to be abstracted from the strata at a sufficient rate for a thick wall of ice to be formed.

The freezing of the north or Tempest shaft was completed, and sinking operations begun in February, 1926. The fissures and cavities in the limestone were well frozen, and the sinking, which was thus quite dry, was conducted in the usual way. Similarly the treacherous sand bed was frozen into a compact mass, and no difficulty was experienced in carrying the shaft through it. A Modern Power Station.

Steam winding engines of the latest type have been installed, the necessary steam for these being supplied by a battery of four boilers capable of evaporating a total of 80.0001b. of jvater per hour. Electrical power for the ventilating fans and other requisite machinery is produced in a special generating station, which at present develops about 1250 horse-power, but which will afterwards be greatly extended. A railway connection lias been made with the st.ait.hs at Seaham Harbour and with the London and North-Eastern Railwav near Hall Dene,

The Marquess adds:—"By taking advantage of all that scientific research has revealed to as, I am aiming in this' new colliery to secure a maximum of efficiency. The Socialists are fond of telling us that nationalisation will bring the millennium. hut I cannot imagine that under the State it would he likely that anyone would embark on what might have seemed a mad idea, that of digging in a Durham turnip field for coal. But that is what I have done. I ought to add. perhaps. that the £1,000.000 which I am spending includes the provision of houses for the miners who will worlk the new colliery."