The preliminary measurement data of the soil resistivity in Yi'an Chong electrode site.

From the perspective of mathematics, the inversion of soil parameters in the N horizontal layer is the optimisation for 2N-1 variables, including soil resistivity of N layer and layer depth of N-1 soil layer.

Ehirim and Ofor [9] used integrated 2D resistivity imaging and vertical electrical sounding (VES) in the study of aquifer vulnerability to surface contamination near two solid waste landfill sites in Port-Harcourt municipality, River State, Nigeria.

Nwankwor [10] employed 2D resistivity survey for groundwater exploration in hard rock terrain: a case study of Magdas observatory, Unilorin.

(4) A gas collection system, using displacement of water and a rotor flow meter, was used to precisely determine the volume of desorbed methane (precision [+ or -]2 mL), while simultaneously recording changes in the collected gas volume and in the

resistivity of the coal sample.

The electrical

resistivity of any material is defined as the resistance between opposite faces of a unit cube of that material.

Go Metals retained Groundtruth Exploration to survey just under 6km in sets of 820m lines at 10 and 5m electrode spacing for

resistivity and induced polarization data.

2(a) corresponds to the model of low

resistivity goaf which shows that the positive peak appears in early period.

The

resistivity of the ultra-soft soil was measured using the conductivity meter and with the measured bulk resistance ([R.sub.b]) at high frequency, a calibration factor was quantified, which could be used for measuring the changes in the electrical

resistivity for the ultra-soft soil.

RES2Dinv Software was utilized to calculate the values of electrical

resistivity. RES2Dinv software is based on the least squares method and uses the finite element (FE) and finite difference (FD).

It consists of extracting the absurd values of the apparent

resistivity (0<Rho<10000) and the X and Y corresponding positions.

In order to determine the porosity and mineralogy of rocks, one can use two physical properties: electrical

resistivity and magnetic susceptibility [21, 22].