Computer simulation sandstone

Computer simulation of the weathering of a pyrite rich sandstone ... 

Gourmelon C., Nichard G., and Boulegue J., Netastable equilibria in sulfide rich waters. Application to a computer simulation of the weathering of pyrite rich sandstones and sulfide ore formation, p. 56-65, in "Proceedings of 2nd Intern. Symp. on Water-Rock Interaction , vol. 4, Sciences Geologiques, Uni-versite de Strasbourg, 1977. 

First, MINTEQ was used to calculate the partial pressure of CO2 gas in equilibrium with the two fluids listed in Tkble III. Based upon measured alkalinity and pH, the raw L2 leachate (point 1, Figure 2) was computed to have a CO2 pressure of 1(> atmosphere. After 5-day reaction with the Uinta Sandstone (point 4, Figure 2), the measured pH and alkalinity of the fluid yielded a calculated CO2 pressure of 1(> atmosphere. Leachate recarbonation was simulated by fixing the CO2 gas partial pressure of the unreacted fluid in the absence of sandstone at the theoretical value of atmosphere (point 2, Figure 2), and in the presence of sandstone at the value of 1(> atmosphere calculated from leachate chemistiy (point 3, Figure 2). It is assumed that, when open to the atmosphere, the system will ultimately approach equilibrium with ambient CO2 pressure (in Boulder) of 10 atmosphere (point 5, Figure 2). 

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