A: Percentage of silica (absolute), SiO_{2}
B: Percentage of alumina, Al_{2}O_{3}
C: Percentage of sesquioxide, Fe_{2}O_{3}
D: Percentage of lime carbonate, CaCO_{3}
===+============================+=======+=======+=======+=======+
No.| Location. | A | B | C | D |
---+----------------------------+-------+-------+-------+-------+
1.| Arroyo Seco, near | | | | |
| brickyard at Monterrey | 60.10 |17.95 | 2.89 | 8.01 |
2.| Arroyo Seco, near | | | | |
| brickyard at Monterrey, | | | | |
| No. 2 | 42.92 |14.26 | 4.66 | 34.58 |
3.| Near Garcia Station, | | | | |
| Mexican National R. R., | | | | |
| Chiquito River, No. 1 | 50.22 | 9.72 | 1.44 | 34.62 |
4.| Near Garcia Station. | | | | |
| Mexican National R. R., | | | | |
| Chiquito River, No. 2 | 48.7 | 4.92 | 8.28 | 35.43 |
5.| San Luis Potosi | 85.02 | 5.00 | 7.38 | 2.21 |
6.| Topo Grande, Pesqueria | | | | |
| River | 40.20 | 5.15 | 4.25 | 46.50 |
7.| Hornos, near Torreon | 77.9 | 13.1 | 2.4 | 4.9 |
8.| Salinas River, at Salinas | 41.5 | 5.7 | 1.4 | 48.2 |
9.| Pits near Caballeros, on | | | | |
| Tampico Branch of | | | | |
| Mexican Central R. R. | 73.4 | 5.6 | 4.4 | 10.1 |
10.| Santa Catarina River, | | | | |
| near San Geronimo | | | | |
| (washed sand) | 12.40 | 2.06 | 1.14 | 81.70 |
11.| Santa Catarina River, | | | | |
| at Monterrey | 17.4 | 2.50 | 2.00 | 77.00 |
12.| Composition of rock, quarry| | | | |
| in foot-hills opposite | | | | |
| Monterrey, Monterrey | | | | |
| Water-Works and Sewer | | | | |
| Company's property | 40.44 | 15.70 | 2.20 | 34.30 |
13.| Manufactured sand from | | | | |
| above quarry | | | | |
| (run of crusher) | 51.80 | 12.14 | 8.7 | 32.6 |
| | | | | |
===+============================+=======+=======+=======+=======+
The chief sands used for ordinary building purposes in Monterrey are
Nos. 10 and 11, which are procured from the bed of the Santa Catarina
River. As these sands contain large proportions of lime carbonates,
which make them very undesirable for important structures, their use was
limited to relatively unimportant work. The best sands procurable were
Nos. 5 and 9, but the long distance of the pits from Monterrey, and
consequently the heavy freight rate, made their use prohibitive on
economical grounds. The best of the available sands, although it was
very fine, was No. 7, from Hornos, near Torreon, as it could be depended
on for uniformity and could be obtained f. o. b. cars at Monterrey for
3.18[5] pesos per ton.
[5] All costs given in this paper are in Mexican pesos, one peso being
equivalent to 50 cents in U. S. currency.
The bulk of the sand and crushed rock used was similar to Nos. 12 and
13, and reference to the cement sand tests in Table 3, will show that
the manufactured sands gave very satisfactory results.
Table 3 gives the average tests made with the "Hidalgo" cement and
various sands, alone and in combination, for the purpose of obtaining
comparative results; the mixtures tested were composed of 3 parts of
sand to 1 of cement.