Method for detecting subsurface mineral bodies using gravity magnetic and topographic surveys

A method for determining a set of surface locations lying along a predetermined line of survey beneath which there is a relatively high probability of existing subsurface mineral bodies having relatively high density and relatively low magnetic susceptibility, the method comprising the steps of:

• determining the relative magnetic field intensity and relative gravitational field intensity at each of a plurality of predetermined surface locations selected along the predetermined line of survey;
• determining the surface elevation at each of the predetermined surface locations;
• selecting for membership in said set a first subset of surface locations at which a local minimum of the magnetic field intensities substantially directly correlates to a local maximum of the gravitational field intensities;
• and,
• selecting for membership in said set a second subset of surface locations consisting of those surface locations lying within each region of local topographic irregularity wherein the gravational field intensity substantially directly correlates with the surface elevation, wherein the step of selecting the second subset is further defined as comprising the steps of:
• filtering the set consisting of the gravitional field intensity at each of the predetermined surface locations;
• filtering the set consisting of the surface elevation at each of the predetermined surface locations;
• correlating the set consisting of the filtered gravitional field intensities with the set consisting of the filtered surface elevations to produce a set consisting of the second correlation value for each of the predetermined surface locations;
• and,
• identifying for membership in said second subset those surface locations at which the second correlation value exceeds a predetermined positive threshold.

A method for determining a set of surface locations lying along a predetermined line of survey beneath which there is a relatively high probability of existing subsurface mineral bodies having relatively high density and relatively low magnetic susceptibility, the method comprising the steps of:

• determining the relative magnetic field intensity and relative gravitional field intensity at each of a plurality of predetermined surface locations selected along the predetermined line of survey;
• determining the surface elevation at each of the predetermined surface locations;
• selecting for membership in said set a first subset of surface locations at which a local minimum of the magnetic field intensities substantially directly correlates to a local maximum of the gravitional field intensities;
• selecting for membership in said set a second subset of surface locations consisting of those surface locations lying within each region of local topographic irregularity wherein the gravitional field intensity substantially directly correlates with the surface elevation;
• and,
• selecting for membership in said set a third subset of surface locations consisting of those surface loctions lying within each region wherein a steep gradient between a local maximum and an adjacent local minimum of the magnetic field intensities substantially directly correlates with a steep gradient between a local maximum and an adjacent local minimum of the gravitational field intensities, wherein the step of selecting the third subset is further defined as comprising the steps of:
• filtering the set consisting of the magnetic field intensity at each of the predetermined surface locations;
• filtering the set consisting of the gravitational field intensity at each of the predetermined surface locations;
• correlating the set consisting of the filtered magnetic field intensities with the set consisting of the filtered gravitational field intensities to produce a set consisting of the third correlation value for each of the predetermined surface locations;
• and,
• identifying for membership in said third subset those surface locations at which the third correlation value exceeds a second positive threshold.

A method for determining a set of surface locations lying along a predetermined line of survey beneath which there is a relatively high probability of existing subsurface mineral bodies having relatively high density and relatively low magnetic susceptability, the method comprising the steps of:

• determining the relative magnetic field intensity and relative gravitational field intensity at each of a plurality of predetermined surface locations selected along the predetermined line of survey;
• selecting for membership in said set a first subset of surface locations at which a local minimum of the magnetic field intensities substantially directly correlates to a local maximum of the gravitational field intensities;
• and,
• selecting for membership in said set a third subset of surface locations consisting of those surface locations lying within each region wherein a steep gradient between a local maximum and an adjacent local minimum of the magnetic field intensities substantially directly correlates with a steep gradient between a local maximum and an adjacent local minimum of the gravitational field intensities, wherein the step of selecting the third subset is further defined as comprising the steps of:
• filtering the set consisting of the magnetic field intensity at each of the predetermined surface locations;
• filtering the set consisting of the gravitational field intensity at each of the predetermined surface locations;
• correlating the set consisting of the filtered magnetic field intensities with the set consisting of the filtered gravitational field intensities to produce a set consisting of the third correlation value for each of the predetermined surface locations;
• and,
• identifying for membership in said third subset those surface locations at which the third correlation value exceeds a second positive threshold.