TNAG-0759-FCO40-963-Manufacture-and-storage-of-explosives-in-Hong-Kong-1978 — Page 27

1

CONFIDENTIAL

6.

3

The 7,000,000 lbs. of Irogel slurries supplied to the High Island Reservoir project and referred to in a.2 has been a successful operation. However, this type of bulk explosive is suitable only for 'down the hole' loading into holes larger than 3 in. dia., it bears little relevance to production of small and medium sizes cartridged watergel.

7.

Although much safer to manufacture than dynamite watergel is not simple to produce. Being vitally dependant on a procice chemical mixture of two or three components it is less tolorant to variatious in manufacture than dynamito and calls for very careful manufacturing control. This is especially so in the cap-sensitive small dia. range where the proportion of sensitizer in the mix has to be increased to maintain a suitable detonation velocity. It is in this area where I.C.I.'s experience and capabilities are less well established than Du Pont's.

&.

I.C.I. and its subsidiary companies have produced worldwide considerable quantities of cartridged watergel explosives including supply for the U.K. market, however their production is almost exclusively of the medium and larger sizes i.c. 2 in. dia. upwards. As far as is known

24 nowhere do they produce small dia. cartridges for general salo, such production that has taken place has been for trial and experimental purposes. All the small dia. watergel marketed in Hong Kong for I.C.I. has been manu- factured in the U.S.A. by Ireco Chemicals.

9.

Regarding test programme firing referred to in 2.4 I.C.I. was not neked to carry out trials with the 24 in. dia. IREGEL explosive because it had been clearly established through general use in quarries and site formations that this explosive was a suitable replacement for dynamite. They were urged to demonstrate that the small dia. IREMITE could be relied upon as a replacement for dynamite especially in difficult tunnelling situations. This they attempted to do with mixed results, from outright failure to a qualified success. Ultimately two of I.C.I.'s technical experts spent a month with one of the Mass Transit Railway contractors and did demonstrate that IREMITS 80 1 in. dia. watergel explosive could substitute for dynamite with suitable charge concentration and placement of holes.