£3,200,000 Tunnel to Shorten Thatnes Crossings I N conjunction with the
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joint committee representing 'Essex and Kent County Councils, Mr. L. Hore-Belisha, Minister of Transport• has made arrangements for work to begin in the course of the next few weeks on the construction of the Dartford-Purfleet Tunnel.
This will provide a much-needed link between the north and south sides of the Thames Estuary and will, it is estimated, cost about 23,200,000. At present there is no facility for crossing the Thames by means of a bridge or tunnel below Blackwall Tunnel, which is 35 miles from the mouth of the Thames Estuary and about 12 miles from the site of the proposed Dartford Tunnel.
The tunnel will he rather more than a mile long. On the north side of the Thames the approach will connect with the Purfleet-Grays Road and an extension is proposed to link up with the London-Southend Road. On the south side the approach to the tunnel will cbanect with the Dartford Southern B'-pass and a connection is to be made with the London-Folkestone and London-Hastings roads.
As a first step, it is proposed to build a pilot tunnel, shield chambers and to carry out certain other ancillary works in connection with the main tunnel. This will be executed by Charles Brand and Sons, Ltd.
The pilot tunnel will be constructed to an internal diameter of 12 ft. and will be approximately 900 yds. long.
Two ventilation shafts with an internal diameter of 18 ft. will be bored on the Kent and Essex banks, of the river, and at the foot of each shaft a shield chamber, 35 ft. in internal diameter, will Le prcvided as a starting-off point for the main tunnel when this is constructed at a later date. The shafts will be about100 ft.. deep and the depth of the pilot tunnel below the existing bed of the river will be 20-25 ft.
The temporary access road on the Kent side will be about mile long and that on the Essex side more than
mile, including two temporary bridges to be laid over railways. These roads will be incorporated in the per
manent apProaChes, so Put aS this is practicable.
The pilot tunnel and ancillary work will cost approximately 300,000 and will provide information as to the strata under the river at this point and on other matters, which will be helpful in connection with the building of the main tunnel. The construction, at this stage, of the shield chambers for the main tunnel will result in a saving of time and money when the principal work is commenced, It has been agreed on behalf of Essex and Kent County Councils that the Ministry of Transport should be directly responsible for carrying out the work.