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Information Only
VII-3
As mentioned in the summary, additional potash core holes have been drilled in
the area by mining or exploration companies, mostly to the west. However, the detailed
records, including chemical analyses of suspected ore intercepts, have not been released
to the public at the request of the companies. This restriction applies so long as the
company holds the mineral lease on which the holes were drilled. The 34 such holes that
exist in the map area are shown on Plate 1 but are not listed in Table 1. It is noteworthy
that all holes drilled within the existing WIPP Site have been available to us. For this
reason the calculations within the WIPP Site should be considered as valid.
Hole locations. The locations of most of the 40 holes used in the reserve calculation
are shown on the most current 7.5-minute USGS topographic quadrangle ntaps of the
area. These locations were digitized using in the New Mexico (East Zone) coordinates. In
the few cases where the holes were not shown on the maps, the locations were [ITst
posted on the appropriate quadrangle map using the survey description shown on the
written drill records filed with the BLM Carlsbad office, and then their positions were
digitized using a Calcomp Drawing Board Two. This phase of the work was done by
Thomas R. Mann & Associates, Inc. under contract. That company also compiled the
graphics for Plate 1.
Drill-bole elevations. The written drill record gives the elevation of the hole. The
records then repon formation changes, ore-zone intercepts, assays, etc. referenced as
depths below the surface. These holes were drilled from the early 1950s to the late
1970s, and the surface elevations were surveyed from a variety of benchmarks. To
funher complicate ntatters. some records are to "drill-rig floor" and others to surface
elevations.
The surface elevation was picked at each hole based on the current USGS 7.5
minute quadrangle maps in order to eliminate any survey errors. In cases where the depth
measuring point was the drill-rig floor, a slight error ntay have been induced. However,
potash drilling rigs are sntall units compared to oil-field rotaries, and the floor probably
would be only 2 to 3 ft above ground level. For the purpose of compiling structure ntaps,
the error would thus be insignificant.
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Formation and ore-zone depths. The 1iepths to ore carne from-the John et al.,
(1978) report for all but holes 1-377, 1-456, arid 1-457, for which the data carne from
records at BLM Carlsbad. Forntation depths (Marker Beds) came from Jones (1978) for
the "P-series" of 21 holes drilled by SNL-USGS in 1977 plus ABC NO.8. Formation
depths for all of the remaining 18 holes carne from records at BLM Carlsbad office.
Calculated mineral content and K:O percentage of ore minerals. The calculation
of the percent K:O as sylvite or langbeinite is not a simple process. First, the
suspected ore-bearing interval is selected by'visual examination of the recovered core.
Once the intervals are selected, the core is then split 10ngitudina11y with one half saved
for reference and the other half sent for chemical analysis. In addition to the two ore
minerals, sylvite (KCl) and langbeinite (K2S0..2MgS04)' the ore beds in the Carlsbad
Potash Mining District typically are a mixture of halite, anhydrite, polyhalite, a variety of
other gangue minerals including but potassium-bearing minerals (such as carnallite) and