PERMFILE55696

• Permit No: C1981014
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: EXHIBIT 09 COMPARISON OF REFUSE AND SOIL SUITABILITIES
• Media Type: D
• Archive: No

• In studies conducted in the Davis Gulch area of the western Colorado oil
shale region, Pendleton (1981) evaluated the SAR values of respread topsoil
15 to 25 cm thick over TOSCO II processed oil shale on studies established
five years earlier by Frischneckt and Ferguson (1979). Although no baseline
SAR values were presented in these reports, this material is identical to the
materials evaluated by Berg et. al. (1983). Using the data of Berg, SAR
values of 29 are typical for TOSCO II process oil shale. Pendleton sampled
these sites at interval of 10, 20 and 40 cm or well through the respread
topsoil and into the processed shale. She reported that the highest SAR
value encountered was at the 30 to 40 cm depth which was 4. Since the
baseline SAR value approached 29 it can easiy be concluded that there was
no upward migration of sodium into the respread topsoil. These resuts are
consistent with data presented by Berg et. al. (1983) wherein it was reported
that over time there was a net decease in the soluble salt concentration in
both the respread topsoil and processed shale.
AMENDMENTS USED TO CORRECT SODICITY
Several amendments have been recommended for treatment of sodicity
and the related physical problems of poor structure and dispersion
assoaated with these materials (Richards 1969). The most commonly
recommended amendments include: calcium chloride, gypsum, sulfur, sulfuric
• acid, iron sulfide, aluminum sulfate, lime-sulfur, ground limestone, and
byproduct lime from sugar factories. A review of the merits of these various
amendments is presented in the discussion by Sandoval and Gould (1978).
Several amendments have been tried with varying degrees of
effectiveness in ameliorating the adverse effects of sodic mine spoils.
Sandoval et. al. (1973) reported on the short term results of application of
gypsum to sodic mine spoil in North Dakota. Merrill et. al. (1983b) presented
the long term results of these studies. Dollhopf et. al. (1985) reported on
long term resuts on the application of various calcareous amendments to
sodic spoil at the Decker Mine in southeastern Montana, while Gould (1982)
reported on the results of field trials designed to evaluate various
amendments on sodic mine spoil in northwest New Mexico. The overall
contusion reached by these studies is that sulfuric acid and gypsum appear
to be the most effective amendments to correct the adverse conditions of
sodic spoil. The successfulness of these materials appears to be
proportional to the amount of moisture that is available to leach the calcium
amendments into the soil profile.
Aside from these classic amendment studies, several other amendment
studies are available from the scientific literature.
In perhaps the most detailed study that has yet been conducted on the
characterization on sodic spoil, Hall and Berg (1983) presented data
demonstrating that the initial reductions in sodicity were directly proportional
to the sulfide content of the overburden. Spoil high in sulfides had a 41
• percent reduction in sodicity, as measured by the SAR, in only 90 days of a
wet-dry weathering cycle, while spoil having a moderate to low sulfide content
was reported to have SAR values reduced by only 22 percent. The
corresponding decreases in SAR in all instances were attributed to increases
in the calcium levels. The major factors responsible for the increase in
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