5
as described below. Location, type of sample, and other
descriptive data were entered into the project database.
Samples are archived at NMBGMR for future examination.
A composite sample of the mine feature is collected
once sample units have been identified in a particular mine
feature. Composite samples of waste rock piles were col-
lected, using procedures developed by Munroe (1999) and
the U.S. Geological Survey (USGS) (Smith et al., 2000
Smith, 2007 McLemore et al., 2014 USGS 2023 memo).
This type of sampling is developed by the USGS and poses
no stability or erosion risks of the waste rock piles or tail-
ings. Each sampling unit should be subdivided into at least
30 cells of roughly equal area. To do this, flags/markers are
placed equidistant from each other forming a rough grid,
where the flag/maker represents the center of each cell
(Figure 4). If a particular subsample location is inacces-
sible, an alternative may be selected as close to the original
location as possible. GPS locations should also be recorded
simultaneously, while placing flags/markers or while remov-
ing flags/markers after sampling. The overburden or overly-
ing surface material (i.e., leaves, grass, roots, cover material
of tailings, etc.) is first removed. Care should be taken when
removing the cover material from tailings to avoid dilution.
Collect each subsample using identical procedures. Collect
the desired volume into the required sieve size (e.g., 2 mm
and 4 mm for tailings and waste rock piles respectively),
and sieve into a single decontaminated bucket or bag,
making sure to homogenize as you sample (Figure 5). For
tailings samples that are wet upon collection, the samples
should be air dried prior to sieving and any particle agglom-
erates, which can form especially upon drying a wet sam-
ple, should be disaggregated before sieving. You can collect
chip samples as well (especially for waste rock piles where
a large percentage of the material is coarse) from the over-
sieved material into a separate bucket or bag and broken
into chips to remove weathering surfaces. Finally, all the
composite samples (fines and coarse) should be thoroughly
homogenized again and then transferred into appropriately
labeled sample containers.
Select samples include hand specimens of mineralized
rocks (including ore samples), grab samples of the mine
wastes, samples from individual cells, etc. from anywhere in
the mine feature and are collected for specific purposes (to
identify minerals, separate chemical analyses, etc.). These
samples are collected separate from the composite sam-
ple. The volume or number of samples collected is highly
dependent on the type of laboratory test to be conducted
and the availability of the sample. Remove weathering sur-
faces from rock samples. If the purpose of sampling is for
geochemical analysis, break samples into smaller chips.
Grab samples should be collected directly from the mine
waste feature or the base of the slope to avoid sampling just
float material. Store the sample in a well-labeled bag.
Profile samples are generally collected along a vertical
exposed section of the mine feature (Figure 6). The soil pro-
file may be exposed, or a small pit may be dug to reveal a
profile. The depth of the pit is dependent on depth of the
mine waste feature. Use a small trowel to clean the surface
of the profile gently to prevent the boundary lines from
caving in. Identify the changes in different lithologies (i.e.,
color, thickness, depth texture, grain size, etc.) and record
them in the field notebook. Collect samples carefully by
scraping directly into a well-labeled sample bag, (include
sampling depth on the sample bag) or decontaminated
container using a small trowel or scoop to avoid cross-con-
tamination from different lithologies. In addition, sample
from the midpoint of the profile as much as possible, sam-
pling the boundary can result in mixing lithologies. Assign
Figure 4. Arrows pointing to subsamples forming a
composite sample of a waste rock pile at Copper Flat
Figure 5. Sieving mine waste rock pile samples
as described below. Location, type of sample, and other
descriptive data were entered into the project database.
Samples are archived at NMBGMR for future examination.
A composite sample of the mine feature is collected
once sample units have been identified in a particular mine
feature. Composite samples of waste rock piles were col-
lected, using procedures developed by Munroe (1999) and
the U.S. Geological Survey (USGS) (Smith et al., 2000
Smith, 2007 McLemore et al., 2014 USGS 2023 memo).
This type of sampling is developed by the USGS and poses
no stability or erosion risks of the waste rock piles or tail-
ings. Each sampling unit should be subdivided into at least
30 cells of roughly equal area. To do this, flags/markers are
placed equidistant from each other forming a rough grid,
where the flag/maker represents the center of each cell
(Figure 4). If a particular subsample location is inacces-
sible, an alternative may be selected as close to the original
location as possible. GPS locations should also be recorded
simultaneously, while placing flags/markers or while remov-
ing flags/markers after sampling. The overburden or overly-
ing surface material (i.e., leaves, grass, roots, cover material
of tailings, etc.) is first removed. Care should be taken when
removing the cover material from tailings to avoid dilution.
Collect each subsample using identical procedures. Collect
the desired volume into the required sieve size (e.g., 2 mm
and 4 mm for tailings and waste rock piles respectively),
and sieve into a single decontaminated bucket or bag,
making sure to homogenize as you sample (Figure 5). For
tailings samples that are wet upon collection, the samples
should be air dried prior to sieving and any particle agglom-
erates, which can form especially upon drying a wet sam-
ple, should be disaggregated before sieving. You can collect
chip samples as well (especially for waste rock piles where
a large percentage of the material is coarse) from the over-
sieved material into a separate bucket or bag and broken
into chips to remove weathering surfaces. Finally, all the
composite samples (fines and coarse) should be thoroughly
homogenized again and then transferred into appropriately
labeled sample containers.
Select samples include hand specimens of mineralized
rocks (including ore samples), grab samples of the mine
wastes, samples from individual cells, etc. from anywhere in
the mine feature and are collected for specific purposes (to
identify minerals, separate chemical analyses, etc.). These
samples are collected separate from the composite sam-
ple. The volume or number of samples collected is highly
dependent on the type of laboratory test to be conducted
and the availability of the sample. Remove weathering sur-
faces from rock samples. If the purpose of sampling is for
geochemical analysis, break samples into smaller chips.
Grab samples should be collected directly from the mine
waste feature or the base of the slope to avoid sampling just
float material. Store the sample in a well-labeled bag.
Profile samples are generally collected along a vertical
exposed section of the mine feature (Figure 6). The soil pro-
file may be exposed, or a small pit may be dug to reveal a
profile. The depth of the pit is dependent on depth of the
mine waste feature. Use a small trowel to clean the surface
of the profile gently to prevent the boundary lines from
caving in. Identify the changes in different lithologies (i.e.,
color, thickness, depth texture, grain size, etc.) and record
them in the field notebook. Collect samples carefully by
scraping directly into a well-labeled sample bag, (include
sampling depth on the sample bag) or decontaminated
container using a small trowel or scoop to avoid cross-con-
tamination from different lithologies. In addition, sample
from the midpoint of the profile as much as possible, sam-
pling the boundary can result in mixing lithologies. Assign
Figure 4. Arrows pointing to subsamples forming a
composite sample of a waste rock pile at Copper Flat
Figure 5. Sieving mine waste rock pile samples