========================================+============================== | FOR 1,095 PIPES 55.9 CM. | IN DIAMETER. Materials. +-------------+---------------- | Quantities. | Cost. ----------------------------------------+-------------+---------------- Portland cement, at 8.00 pesos per | | bbl., delivered at pipe-making yard. | 303 bbl. | 2,424.00 pesos. Sand, at 2.65 pesos per cu. m. | 68 cu. m.| 180.20 " Crushed rock, 19-mm. (3/4-in.), at 2.65 | | pesos per cu. m. | 50 cu. m.| 132.15 " No. 6 galvanized-wire hoops. 4 rings | | to each pipe. | 4,380 | 183.00 " ----------------------------------------+-------------+---------------- Totals. | ... | 2,919.45 pesos. ----------------------------------------+-------------+---------------- Cost per pipe. | ... | 2.66 pesos. ========================================+=============+================ _Excavation for Pipe Line and Siphons._--The excavation for the pipe line and for bridge works, etc., was let by contract to Messrs. Scott and Lee, of Monterrey, under three classifications: (1) "All material which in the judgment of the Engineer can be economically loosened with picks and handled with shovels." (2) "Indurated earth or gravel, shale or rock which can be loosened without blasting, and 'sillar', locally so-called, whether pure or mixed with other substances, and whether it requires blasting or not." (3) "All rock not included in the above which requires drilling or blasting." Locally, this classification is well understood, particularly No. 2, as it covers the sillar soils which are common in the neighborhood of Monterrey. The contract prices were: No. 1, 50 cents; No. 2, 1.50 pesos; and No. 3, 2.50 pesos per cu. m. These prices were over and above the clearing and grubbing of the line, which was paid for at the rate of 100 pesos per hectare. The route of the pipe line being along broken country, at some points difficult of access, service roadways, about 3 m. wide, for hauling material were constructed, and, for about 7 km., a roadway was made along the line of the trench. The prices for the roadway, under the above classification, were: For No. 1, 35 cents; No. 2, 1.50 pesos; and No. 3, 2.50 pesos per cu. m. The trenches were excavated 5 cm. below the required finishing depth, to allow for grading the pipes in selected material, and were taken out to an average width of 40 cm. greater than the outside diameter of the pipe, to allow for their proper jointing, and also to give sufficient room to roll the pipes in the trenches.