269. Normal maintenance included the clearance of stream beds, the replacement of corroded steel pier and bridge members and the underpinning of scoured bridge abutments and pier foundations. Damage caused by the heavy rainstorms in May necessitated repairs to four bridges at Sek Kong, Yuen Long, Sheung Shui and Tai Po.
270. At the request and expense of the Military Authorities, seven bridges in the New Territories were strengthened and the construction of a reinforced concrete pier to support the Bailey Bridge at Tai Po commenced.
QUARRIES
271. The two quarries, operated with direct labour, produced 242,396 tons of stone from which 106,180 tons of bitumen coated stone were manufactured. The total value of these products amounted to approximately $4,200,000. The Mount Butler Quarry satisfied all demands made upon it, and operated well within the capacity of the premix plant for the greater part of the year; but the Hok Yuen Quarry, in spite of producing more stone than ever before, could not meet the heavy demands of Kowloon and the New Territories.
272. The following table shows the output of the quarries over the last four years:
Quarry Total Stone (Tons) 57-58 58-59 59-60 60-61 Hok Yuen 93,089 112,225 115,516 122,604 Mt. Butler 44,780 122,961 109,419 119,792 Total 137,869 235,186 224,935 242,396 Bituminous Mixes (Tons) 57-58 58-59 59-60 60-61 Hok Yuen 37,303 39,957 51,184 72,392 Mt. Butler 30,899 41,248 44,120 33,788 Total 68,202 81,205 95,304 106,180273. The increase in the production of bituminous mixes at Hok Yuen is worthy of note. This amounted to 21,208 tons or 41% more than the previous year; this was made possible by the new plant brought into operation in December, 1959.
274. In conjunction with the consulting engineers, Messrs. Scott and Wilson, Kirkpatrick and Partners, tests and trials, designed to produce a better bituminous wearing surface for roads, were carried out, principally in connexion with the surfacing of Lung Cheung Road. Although these tests covered a wide range, the product finally selected varied only slightly from that which has been produced in bulk by the quarries for some years.
275. On a smaller scale tests of special heavy duty mixes produced promising results.
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