Increase in pH through a calcite barrier

To increase the pH of the acid mine drainage from the exercise in chapter 3.1.6.2 a reactive wall of 1 m thick calcite (density of calcite = 2500 kg/m3) shall be installed within the aquifer. Thickness and permeability of the wall are chosen in a way that a 50 % saturation of lime in the aquifer can be reached with a daily percolation of 500 L/m2. 

Does the calcite wall lead to the desired increase of the pH value And why are there still objections against the reactive calcite wall taking into account the longterm efficiency and premature alteration Which carbonates could be chosen alternatively to calcium carbonate to avoid a premature alteration  

---