4
METHODS
Sample Collection
Different sampling strategies will be employed based upon
the purpose of each sampling task. Several types of samples
were collected: composite, select, profile samples, compos-
ite mine waste, and drill core samples as described below.
Samples are archived at NMBGMR for future examina-
tion. Two separate splits of each samples are generally col-
lected: one split for chemical analyses that is submitted to
the chemical laboratory and a second split that is archived
at NMBGMR. Selected sample sites are marked on topo-
graphic maps and a digital photograph is taken at all locali-
ties. Photographs provide visual record of the sample site
the photograph form identifies site specifics, provides basic
location and other data about the photograph. Location
information by GPS, type of sample, and field and labo-
ratory petrographic descriptions are collected. Geologic
observations are recorded on the field description form or
field book. A global positioning system (GPS) reading is
recorded as well. Hand specimen description provides a
record of what was collected, aids in petrographic descrip-
tion, and provides information on sample for the labs (high
S may be treated differently than low S). The hand specimen
description is the preliminary data required to determine
what samples need specific detailed analyses. Location, type
of sample, and other descriptive data were entered into the
project database.
Composite samples include sampling along the width
and thickness of the sedimentary layer or bed in order to
obtain a representative sample of the unit. Multiple sub-
samples are collected and homogenized for a composite
sample.
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 or outcrop being sampled and are collected for
specific purposes (to identify minerals, separate chemical
analyses, etc.). These samples are collected separate from
the composite sample. 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 surfaces from rock samples. If the purpose of
sampling is for geochemical analysis, break samples into
smaller chips. Store the sample in a well-labeled bag.
Profile samples are generally composite samples col-
lected from individual stratigraphic layers or beds along a
vertical exposed section of an outcrop, road cut, or open
pit wall, if safe. Use a pick to clean the surface of the pro-
file gently to prevent the edges from caving in. Identify the
changes in different lithologies (i.e., color, thickness, depth
texture, grain size, etc.) and record them in the field note-
book. 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
pick, trowel or scoop to avoid cross-contamination from
different lithologies. In addition, sample from the mid-
point of the profile as much as possible, sampling the edge
can result in mixing lithologies. Assign one GPS location
and waypoint to the pit and different sample IDs to each
lithology sampled.
Figure 3. Humate mine in the Star Lake field, northern New
Mexico. The humate is the upper brownish layers overlying
the black coal
Figure 4. Brick-red clinker deposits in the San Juan Basin
coal fields
METHODS
Sample Collection
Different sampling strategies will be employed based upon
the purpose of each sampling task. Several types of samples
were collected: composite, select, profile samples, compos-
ite mine waste, and drill core samples as described below.
Samples are archived at NMBGMR for future examina-
tion. Two separate splits of each samples are generally col-
lected: one split for chemical analyses that is submitted to
the chemical laboratory and a second split that is archived
at NMBGMR. Selected sample sites are marked on topo-
graphic maps and a digital photograph is taken at all locali-
ties. Photographs provide visual record of the sample site
the photograph form identifies site specifics, provides basic
location and other data about the photograph. Location
information by GPS, type of sample, and field and labo-
ratory petrographic descriptions are collected. Geologic
observations are recorded on the field description form or
field book. A global positioning system (GPS) reading is
recorded as well. Hand specimen description provides a
record of what was collected, aids in petrographic descrip-
tion, and provides information on sample for the labs (high
S may be treated differently than low S). The hand specimen
description is the preliminary data required to determine
what samples need specific detailed analyses. Location, type
of sample, and other descriptive data were entered into the
project database.
Composite samples include sampling along the width
and thickness of the sedimentary layer or bed in order to
obtain a representative sample of the unit. Multiple sub-
samples are collected and homogenized for a composite
sample.
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 or outcrop being sampled and are collected for
specific purposes (to identify minerals, separate chemical
analyses, etc.). These samples are collected separate from
the composite sample. 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 surfaces from rock samples. If the purpose of
sampling is for geochemical analysis, break samples into
smaller chips. Store the sample in a well-labeled bag.
Profile samples are generally composite samples col-
lected from individual stratigraphic layers or beds along a
vertical exposed section of an outcrop, road cut, or open
pit wall, if safe. Use a pick to clean the surface of the pro-
file gently to prevent the edges from caving in. Identify the
changes in different lithologies (i.e., color, thickness, depth
texture, grain size, etc.) and record them in the field note-
book. 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
pick, trowel or scoop to avoid cross-contamination from
different lithologies. In addition, sample from the mid-
point of the profile as much as possible, sampling the edge
can result in mixing lithologies. Assign one GPS location
and waypoint to the pit and different sample IDs to each
lithology sampled.
Figure 3. Humate mine in the Star Lake field, northern New
Mexico. The humate is the upper brownish layers overlying
the black coal
Figure 4. Brick-red clinker deposits in the San Juan Basin
coal fields