The application of vertical magnetic contouring in estimating the extent of Precambrian iron formations in the Schefferville district

Magnetic surveys were conducted at surface and at different altitudes over magnetic taconite iron deposits. The magnetic observations are presented under the form of vertical sections. This information allows on-site experimental optimization of flight line spacing and flight altitude for aero and helicopter borne magnetic surveys which are under way or are planned for future exploration programmes. It also provides a means for determining the width of the buried causative body, its depth of burial below the plane of observation and the relative importance of the natural remnant magnetic component. A great many examples selected on a large variety of sites underlain by magnetic taconite deposits allowed a comparison of the calculated parameters with actual depths, widths and natural remnant magnetic vectors. A few of these vertical magnetic sections are presented in this paper.