Problem $1(50$ points$)$

From drillhole data compiled in Table $1,$ and the coal seam shown in Figure $1$ calculate the:

a$)$ average seam thickness $(6$ points$]$

b$)$ average depth of overburden $(6$ points$)$

c$)$ average analysis in percent sulfur $(6$ points$)$

d$)$ total tons of reserve $(6$ points$)$

Exploration has been conducted through vertical boreholes, spaced equidistant in a triangular grid $($Fizure $1$a$).$ Tonnage factor for coal is $\backslash (25\backslash$mathrm$\{$ft$\}^\{2\}/\backslash )$ ton. Note that this is a tabular deposit and you may base statistical averages on area instead of volume.

e$)$ Sketch the areas of influence on the plan view $($Figure $12),$ using the polygon method and assuming that the areas of influence for the outside holes run to the outcrop or the boundary of the property. $(13$ points$)$

f$)$ Calculate the overall stripping ratio in feat of overburden removed per foot of coal removed. $(13$ points$)$

Table $1.$ Dril hole Data

Figure $1.$ plan view $($a left$)$ and section view $($b right$)$ coal deposit in Problem $2$