Information Only - Waste Isolation Pilot Plant - U.S. Department of ...

present. Please note the position of the "16" contour on Figure 4. The material inside
that contour meets the BLM Lease Grade reserve criteria of 4 % K 2 0 (or equivalent)
langbeinite at a 4 ft mining height. Also note the approximate position of the "37.5"
contour which represents the criterion on economic mining.
VII-IO
Figures 5 through 12 are histograms of the resources that were adjusted for
mining thicknesses from 4 up to 7 ft for the entire study (gridded) area, and Figures 13
through 20 are histograms for the same data within the WlPP Bouodary. Figures 21
through 24 present the histogram data in tonnage-summation-curve formats to determine
reserves as a function of cutoff grade or as a function of the average grade, again for the
entire study area and for within the WIPP bouodary. Calculation of the reserves outside
of the WlPP bouodary was a simple matter of subtraction.
A summation of the cell data for the 4th are zone was made of the three significant
criteria and partitioned by areas. The results are in Table 2.
The resource and reserve estimates are valid within the WIPP boundary because
all drill-hole information within that boundary were available and the spacing of the holes
was on the order of one-mile centers.
The tonnages and grade outside of the WlPP bouodary were estimated in accordance
with the grid generated by the MacGridzo computer program that extended out to
the furthest drill holes in all cardinal directions. Referring to Figure 4, note that the "16"
contour, which determined the 8LM Lease Grade reserve, defined a large reserve that
extends north and east of the WIPP Site. Also note there was a sufficient number of holes
in that area to justify classification as drill-deftned reserves. The same held true for our
estimate of minable reserves (defined by the "37.5" contour) for that area.
8LM Lease Grade reserve in a separate location was evident on the west, dermed
by holes 12, 14, 48, 104, and 120. However, the information base did not include several
industry-drilled holes along the west flank of the WIPP Site (see Plate 1 for the locations
of these holes because they are not shown elsewhere), which would have improved the
estimate of reserve in that area. Nonetheless, the estimate of 8LM Lease Grade reserve
appears to be reasonable within one mile west-Of the WIPP boundary. It is important to
note that minable reserve (defined by the "42"·'contour in Figure 4) does not exist within
one mile of the WIPP boundary on the west. Similarly, the 4th ore zone boundaries were
well defined but a potential for additional discoveries exists in the southwest portion of
the study area where few exploratory holes exist.
Figures 2S and 26 were used to measure the degree to which the 4th ore zone
contained mixed ore. It was apparent that the northeast portion of the mineralized area
was simply langbeinite and contained the major portion of the resources and reserves for
that ore bed. Therefore, exclusion of the sylvite portion for determination of equivalent
% KzO had little effect on the determination of reserves in the northeast. However, the
presence of sylvite was important in derming 8LM Lease Grade reserves in the northwest.
Figure 27 is a struetural contour map of the top of the 4th ore zone. The map is
Information Only