FIGURE 28- Compute angle O shown in Fig. 2Bd; determine the strike
of the vein, using Eq. 49
Thus, 6 = 180° + <£i - <fe = 14O^0 OO'; m = tan ft/tan /S 1 = 0.6406; tan O 1 = (m - cos
140°00')/sin 14O^0 OO'; (^0) t = 65°26'; O 2 = 74°34' The bearing of the horizontal projection
of the dip line = ^ 1 - ^ 1 = S61°22'E; therefore, the strike of the vein = N28°38'E.
- Compute the dip a of the vein
By Eq. 48, tan a = tan /B 1 IcOs O 1 ; a = 52°12'; or tan a = tan /3 2 /cos O 2 ; a = 52°14'. This
slight discrepancy between the two computed values falls within the tolerance of these
calculations. Use the average value a = 52° 13'. - Establish the reiationship between the true thickness t
of a vein and its apparent thickness f' as measured along a
skew borehole
Refer to Figs. 27 and 28. Let 8 = angle of inclination of borehole; y = angle in plan be-
tween downward-sloping segments of borehole and dip line of vein. Then
(d) Plan
Plan(b) Elevation normal
to HaHbDatum