Abstract
The airborne magnetometer data of the Marmora iron ore deposit at Marmora, Ontario have been used as an example to show the results obtained by the use of various line spacings ranging from 1 mile to 1/4 mile. The maps show how easy it is, in any type of geophysical survey, to miss a feature of economic value if the line spacing is too coarse.
The probability equations are given for the crossing of randomly oriented features whose maximum dimension is less than the spacing of the control lines for circular, elongate, and rectangular outlines. The equations are P=D/S; P=2L/πS; P=2(L+W)/πS; P=A/πS; P=(2L(S+T)-L2)/πST; and P=(D(S+T-πD))/ST; respectively where P is the probability; D is the diameter; L is the length; W is the width; and S and T are line spacings.
