Mg-rich ultramafic rocks can spontaneuously capture atmospheric $\textrm{CO}_2$ through mineral carbonation. For this reaction to occur, the residues must be exposed to sufficient water and $\textrm{CO}_2$ concentrations. In order to better understand mineral carbonation at industrial scale and determine if we could identify variations in physical properties of carbonated materials, a borehole was drilled into chrysotile milling waste pile located in Thetford Mines, Québec, Canada. Electrical resistivity, magnetic susceptibility and borehole radar data were acquired in the borehole.  These field data have allowed us to propose a petrophysical model that explains the measured increases in electrical resistivity and the reduction in magnetic susceptibility observed within the alteration zones suitable for the formation of magnesium carbonates. The growth of the carbonates, inherently resistivite in nature, restricts water ingress which further contributes to increases in electrical resistivity. The observed reduction of magnetic susceptibility comes from the weathering of magnetite and the serpentine. The iron that is leached out during this process precipitates as an iron hydroxide. The proposed petrophysical model is validated through petrographic and chemical composition analysis. These analyses also revealed that the level of destruction of the magnetite provides insights into the maturity of the alteration reaction that is caused by in-situ weathering.These results represent the first step in quantifying the volume of magnesium carbonates that are hosted in these mining residues and track the progress of the reaction in time. With foresight and clever design, mining waste may become an interesting carbon sink proposition for the mining industry who could strive to become carbon neutral.