4
existing technical report conveys. The saw-tooth contacts
indicate the lack of any discussion of the pit in the report.
In spite of the optimistic estimates, the report called for
more drilling. Therefore, in the year prior to my arrival the
landowner contracted for a flight auger and drilled in the
exact same locations as the filled track hoe test pits on the
lower terrace. All drill holes showed sand and gravel from
top to bottom. The backhoe also dug a number of test pits
in the wetlands, which revealed white quartz gravel simi-
lar to the metallurgical gravel being produced in a nearby
pit. That gravel was off-limits because it was located in the
wetlands.
In-Depth Geologic Study
I was retained by a potential partner to determine the qual-
ity and quantity of the metallurgical gravel, to determine
the amount of overburden, and to opine on the reasonabil-
ity of reopening the Ole Gravel Pit to mine and process the
metallurgical gravel. Although I was retained by the poten-
tial partner, he and the landowner freely exchanged data
and ideas with one another.
Although there was an abundance of existing auger
hole data, there was a complete lack of details regarding
how those data were used to determine reserves (more
appropriately potential reserves). The existing report did
not even mention the geology as exposed in the Ole Gravel
Pit. Although the landowner and potential partner had
been through the pit, they had not studied the pit in any
detail. For example, they had not done the simple job of
determining the altitude of the top or the bottom of the
gravel in the pit walls.
Scheduling set by the client and the owner of the prop-
erty limited my time in the abandoned pit to a chauffeured
drive-through on an all-terrain vehicle. That was sufficient
to determined there was significant overburden on both
the higher and lower terraces but insufficient to get actual
measurements. The time spent in the pit was short because
neither the client nor the landowner were comfortable pro-
jecting knowledge from the pit to the surrounding area.
Furthermore, although there was a dearth of geology in
the existing reports, the client was not interested in having
me conduct a geological study. He and the landowner were
looking for “hard proof” from new drilling and test pits.
A 12-inch solid stem flight auger and a track hoe were
made available to assist me in my evaluation. The first task
was to drill two holes within about 10 feet of two of the
previous drill holes on the higher terrace. The side-by-side
comparisons showed that the original study grossly under-
estimated the overburden on the higher terrace.
The drilling that the landowner had done in the
footprints of the track hoe test pits on the lower terrace
showed that gravel extended to the land surface. I tested
that observation with an auger hole drilled adjacent to, but
not directly in, one of the track hoe test pits. To the con-
trary, there was approximately ten feet of overburden before
encountering gravel. Apparently, the owner encountered
blended backfill material and erroneously assumed that the
gravel deposit extended continuously from the land surface
to the bottom of the deposit.
Abundant, highly weathered, weak silica gravel (locally
referred to as “sugar rock”) was encountered in the test pit.
Sugar rock cannot be used as metallurgical gravel, and is
commonly passed up for use as construction aggregate.
The track hoe was used to excavate a continuous trench
from the crest of the lower terrace to the floodplain in the
valley. Beginning about 10 feet below the crest of the ter-
race, a weathered silica gravel with a disoriented fabric was
observed on the entire hill slope.
I encouraged the client to accompany me to the gravel
pit where I gave a verbal report to help him visualize the
Figure 2a. Distribution of potential metallurgical gravel when not considering geology
existing technical report conveys. The saw-tooth contacts
indicate the lack of any discussion of the pit in the report.
In spite of the optimistic estimates, the report called for
more drilling. Therefore, in the year prior to my arrival the
landowner contracted for a flight auger and drilled in the
exact same locations as the filled track hoe test pits on the
lower terrace. All drill holes showed sand and gravel from
top to bottom. The backhoe also dug a number of test pits
in the wetlands, which revealed white quartz gravel simi-
lar to the metallurgical gravel being produced in a nearby
pit. That gravel was off-limits because it was located in the
wetlands.
In-Depth Geologic Study
I was retained by a potential partner to determine the qual-
ity and quantity of the metallurgical gravel, to determine
the amount of overburden, and to opine on the reasonabil-
ity of reopening the Ole Gravel Pit to mine and process the
metallurgical gravel. Although I was retained by the poten-
tial partner, he and the landowner freely exchanged data
and ideas with one another.
Although there was an abundance of existing auger
hole data, there was a complete lack of details regarding
how those data were used to determine reserves (more
appropriately potential reserves). The existing report did
not even mention the geology as exposed in the Ole Gravel
Pit. Although the landowner and potential partner had
been through the pit, they had not studied the pit in any
detail. For example, they had not done the simple job of
determining the altitude of the top or the bottom of the
gravel in the pit walls.
Scheduling set by the client and the owner of the prop-
erty limited my time in the abandoned pit to a chauffeured
drive-through on an all-terrain vehicle. That was sufficient
to determined there was significant overburden on both
the higher and lower terraces but insufficient to get actual
measurements. The time spent in the pit was short because
neither the client nor the landowner were comfortable pro-
jecting knowledge from the pit to the surrounding area.
Furthermore, although there was a dearth of geology in
the existing reports, the client was not interested in having
me conduct a geological study. He and the landowner were
looking for “hard proof” from new drilling and test pits.
A 12-inch solid stem flight auger and a track hoe were
made available to assist me in my evaluation. The first task
was to drill two holes within about 10 feet of two of the
previous drill holes on the higher terrace. The side-by-side
comparisons showed that the original study grossly under-
estimated the overburden on the higher terrace.
The drilling that the landowner had done in the
footprints of the track hoe test pits on the lower terrace
showed that gravel extended to the land surface. I tested
that observation with an auger hole drilled adjacent to, but
not directly in, one of the track hoe test pits. To the con-
trary, there was approximately ten feet of overburden before
encountering gravel. Apparently, the owner encountered
blended backfill material and erroneously assumed that the
gravel deposit extended continuously from the land surface
to the bottom of the deposit.
Abundant, highly weathered, weak silica gravel (locally
referred to as “sugar rock”) was encountered in the test pit.
Sugar rock cannot be used as metallurgical gravel, and is
commonly passed up for use as construction aggregate.
The track hoe was used to excavate a continuous trench
from the crest of the lower terrace to the floodplain in the
valley. Beginning about 10 feet below the crest of the ter-
race, a weathered silica gravel with a disoriented fabric was
observed on the entire hill slope.
I encouraged the client to accompany me to the gravel
pit where I gave a verbal report to help him visualize the
Figure 2a. Distribution of potential metallurgical gravel when not considering geology