Title:
Concrete and Concrete Quality Control
for Mine Shaft Lining
Author(s):
Elwood L. Ore and Jack D. Gilmour
Publication:
Concrete International
Volume:
2
Issue:
5
Appears on pages(s):
29-39
Keywords:
admixtures; aggregates; concrete con-struction;
formwork (construction); linings; mix pro-portioning;
placing; pozzolans; quality control;
temperature.
DOI:
Date:
5/1/1980
Abstract:
The construction work at Mt. Taylor Uranium Mine involved concrete for buildings to house hoists, substation equipment, laboratories, offices, as well as other related activities, and for the lining of two shafts. This project is located near San Mateo, N.M., about 1 IO miles (177 m) from Albuquerque. Mixes were proportioned, batched, mixed, and tested to provide concrete which met the ordinary 3000 to 4000 psi (20.7 to 27.6 MPa) strength require-ment, as well as concrete to be used in the shaft lining having a minimum strength of 5000 psi (34.5 MPa) and being placed in contact with rock formations of progressively higher temperatures during both winter and summer. Chilled water was used to cool the ag-gregate and for mixing, thus controlling the temperature of concrete as the rock formation temperature reached a maximum of 120 F (49 C). Admixtures were used to control the setting time, reduce the water required for high slump concrete, thus im-proving efficiency in the use of cement and achieving greatest economy. Close control of the grading of the sand and the coarse aggregate, the quantity of the mixing water, the entrained air, the accuracy of the measurement of each component, and the impositio of low variation in strength test results permitted the production of concrete of optimum quality.