coal Flashcards
stage in coal production when the mined coal is processed into a range of clean,
graded, and uniform coal products that are suitable for the commercial market
Coal preparation
other term for Coal preparation
(beneficiation)
collected
from the coal streams to power plants on a regular basis not only for determination of
heat balance but also to document compliance with air pollution emission regulations
operating samples
coal handling system,
crushing is limited to a top size of
6 or 4 mm
devices most commonly used for
crushing are the
rotary breaker, the roll crusher, and the hammer mill.
e typical sizes of individual field samples vary from
3 to 15 kg.
he purest form of probability sampling and each member
of the population has an equal and known chance of being selected and bias is minimized
Random sampling
s often used instead of random sampling and, depending
on the material to be sampled, can be as good as the random sampling method
Systematic sampling
commonly used probability method that is superior to random
sampling because it reduces sampling error and is used to select a sufficient number of samples from, say, each level of the coal pile – sufficient refers to a sample
size large enough for us to be reasonably confident that the stratum represents the
population
Stratified sampling
typically used in exploratory research
where only an approximation of the data will suffice
convenience sampling
common
method of sampling and the sample is assumed to be repetitive without and foundation
for this belief and the confidence that the chosen sample is truly representative of the
coal pile is low
Judgment sampling
similar to stratified sampling and then convenience
sampling or judgment sampling is used to select the required number of samples
from each stratum.
Quota sampling
a method used when the desired sample
characteristic is rare and does introduce bias because the technique itself reduces the
likelihood that the sample will represent a good cross section from the population.
Snowball sampling
sample that represents a quantity, or lot, of coal and is
composed of a number of increments on which neither reduction nor division has been
performed
The recommended maximum quantity of coal to be represented by one gross sample is 10,000 tons
gross sample of coal
statistical term defined as the mean square
of errors;
Variance
square root of the variance is more generally known as the
standard
deviation or the standard error of sampling
function of the size of increments collected and the
number of increments included in a gross sample, improving as both are increased,
subject only to the constraint that increment size not be small enough to cause selective rejection of the largest particles present
precision of sampling
) For raw,
dirty, or poorly cleaned coal, the minimum number of increments is
35.
reserved for the collection
of sample increments from a free-falling stream of coal as opposed to the collection of increments from a motionless (stopped) conveyor belt
Stream sampling and flow sampling
only the coal near the top surface has the potential to be
included in the sample thereby violating the basic tenet of obtaining a representative
sample. increments must not be collected predominantly from
any given location relative to the dimensions of the rail car.
car-top sampling
consists of one or more pipes, arranged like the spokes of a
wheel. Openings located at the tips collect the sample as the device is rotated through
coal on a moving belt.
spoon sampler
used as a sampling device for penetrating a stationary
mass of coal and withdrawing material from its interior
auger drill
that includes all other coals, including
unknown coals
B
includes coals that have been cleaned in all sizes and allows smaller weight laboratory
samples to be retained
A
a process by which mineral matter is removed from coal using any
one of several washing processes to leave the coal as near mineral-free as is required
by the buyer or by legislation.
coal washing
present in intimate association
with the pure coal substance itself and originated from inorganic material essential
to the growth of the vegetable matter from which the coal was originally formed.
, intrinsic mineral
matter a
purely adventitious, is derived
from the roof and floor of the coal seam and from any non-coal or inorganic material
that may be associated with the seam itself.
extrinsic mineral matterq
consisting of a Henry tube, is suitable for moderately small graded
coals
hand jig,
o indicate the reliability of a measurement, or an observation but it is, more specifically, a measure of the closeness of agreement between
an experimental result and the true value.
expressed inversely in terms of the standard deviation or variance and includes any systematic error or bias
accuracy
determined by means of cooperative test programs. B
precision
srepresents the occurrence of a systematic error (systematic
errors) that is (are) of practical importance
bias
pathfinder of gold
As, Mo, Ag, Sn, Sb, Te, W, Bi, Ni, and Cu
K-T boundary
65.5 Ma
> 100 ka
feldspars, biotite,
sericite, clays, muscovite, phlogopite,
glauconite, alunite,
amphibole, whole
rocks (e.g. basalts),
volcanic glass
to obtain metamorphic or
crystallization ages
[40K-40Ar]
[40K-40Ca]
> 10 ka
n improved variation of
the K-Ar method requiring neutron irradiation
of materials in a nuclear
best method for elucidating thermal histories
[40K-40Ar]
overcomes limitations
of the K-Ar method by
using
laser ablation and
stepheating techniques
> 50 Ma
K-feldspar, plagioclase, biotite,
sericite, phlogopite,
muscovite, hornblende, whole rocks
must use an isochron
method to derive a
87Rb-87Sr
> 100 Ma
garnet, pyroxene,
mafic and ultramafic rocks (e.g.
basalts)
[
147Sm-143Nd]
> 60 Ma
sulphide minerals,
black shales, mafic
and ultramafic rocks
– useful for studying ore
formation and magma
genesis
187Re- 187Os]
> 5-10
Ma
zircon, titanite,
monazite, rutile,
baddeleyite,
xenotime, apatite
allanite, (U,Th)
oxides
zircon, titanite,
monazite, rutile,
baddeleyite,
xenotime, apatite
allanite, (U,Th)
oxides
[
235U-207Pb]
[
238U-206Pb]
> 5-10
Ma
zircon, monazite
[232Th-208Pb]
> 100 ka
zircon, apatite,
titanite
Ages and/or rates of shallow, low-T (50-200°C) crustal
processes (e.g. neotectonics,
geomorphology)
[232Th-208Pb]
[235U-207Pb]
[238U-206Pb]
< 1Ma coral, carbonates,
clastic sediments,
volcanic rocks
To date sedimentary and
igneous rocks, volcanic processes, sedimentation rates,
magma chamber evolution
U-Th Series
Disequilibriumk
date low-temperature thermal histories
of rocks, rates of
uplift or subsidence
(typically processes
with T < 250°C)
Based on the
atomic-scale damage 238U
atoms. The higher
the track density, the
older the crystal
Apatite, glass, zircon,
titanite, mica, garnet
Fission Track Dating
To date surficial
processes such as
landform formation,
length of exposure,
groundwater, erosion
rates, weathering,
ocean sediments
Based on the production (due to excitation by cosmic rays)
of rare nuclides in
rocks or other materials that are exposed
on the surface of the
earth
Any rock, quartz,
feldspar, organic
material (14C), meteorite
Cosmogenic Exposure
Dating (3He, 14C,
36Cl, 10Be, 26Al)
To date sediments,
volcanic rocks, or
archaeological samples which are typically < 50-800 ka
Based on measuring the amount of
excited electrons
in a crystal held in
metastable states
due to interactions
of ionizing radiation
quartz, alkali feldspar,
carbonates, zircon,
ceramics, glass,
bone, shells
Thermoluminescence
o date sediments,
volcanic rocks, or
archaeological samples which are typically < 50-800 k visible or
near-infrared light is
used to release the
rock’s luminescence.
Optically Stimulated
Luminescence
date sediments,
volcanic rocks,
or archaeological
samples which are
typically Pleistocene
in age or younger
measures the
amount of metastable electrons in a
crystal that has been
exposed to ionizing
radiation. Based on
the absorption of
microwave radiation by the trapped
electrons in a strong
magnetic field.
Calcite, bones, shells,
quartz, corals, volcanic rocks
Electron Spin
Resonance
conodonts
graptolites
ORDOVICIAN
nautiloid cephalopods
trilobites
gastropods
SILURIAN
conodonts
goniatites
brachiopods
gastropods
spores
DEVONIAN
foraminifers
goniatites
conodonts
MISSISSIPPIAN
fusulinids
conodonts
goniatites
radiolarians
PENNSYLVANIAN
fusulinids
conodonts
goniatites
radiolarians
PERMIAN
mollusks
conodonts
TRIASSIC
mollusks
radiolarians
JURASSIC
foraminifers
nannofossils
spore-pollen
radiolarians
CRETACEOUS
mollusks
foraminifers
ostracodes
spore-pollen
siliceous microfossils
radiolarians
TERTIARY
a conformal cylindrical map projection that was originally created to display accurate compass bearings for sea travel.
mercator projection
similar to Mercator except that the cylinder touches the sphere or ellipsoid along a meridian instead of the equator flips the cylinder 90 degrees
transverse mercator projection
flattens the sphere 60 times by shifting the cylinder central meridian 6° for each zone.
UTM projection
sed for countries that span along a longitudinal extent. “many cones,” and it is created by lining up an infinite number of cones along the central meridian. This affects the shape of the meridians.
polyconic projection
All the meridians are equally spaced straight lines converging to a common point, which is the nearest pole to the standard parallels. The parallels are represented as circular arcs centered on the pole. Their spacing increases away from the standard parallels.
lambert conformal conic
e topographic relief and the presence or absence of
contour lines does not hinder geologic interpretation.
small-scale
maps or in areas
describes a line as heading north or south, and deflected some number of degrees toward the east or west. A bearing, therefore, will always have an angle less than 90°.
bearing
a model of global mean sea level that is used to measure precise surface elevations.
geoid
ANNUAL EVAPORATION AND PRECIPITATION of oceans
297 334
ANNUAL EVAPORATION AND PRECIPITATION of land
99 62
lateral changes in
rock types or configurations
of subsurface structures,
location of faults, and depth
to magnetic bedrock in deep
alluvial-filled basins. Also can
be used for detection/mapping of buried drums at
Magnetometry (MAG)
y sending pulses of high
frequency electromagnetic waves into the ground from a transmitter antenna
located on the surface.
plotted in a
distance-versus-time display
Ground Penetrating Radar (GPR)
alternating current in the EM transmitter coil creates
a magnetic field which induces electrical current loops within the ground; the
current loops, in turn, create a secondary magnetic field
Electromagnetic Induction (EM)
e depth to the ground water table or to
perched water tables, water quality, leakage from dams or tailings ponds, corrosion potential of soils,
A voltage difference measured
across a second electrode
pair provides the necessary
information to calculate the
apparent earth resistivity
(the inverse of apparent
Electrical Resistivity Surveys
approximated by matching the data curve to theoretical
curves.
True resistivity
primary
gamma emitting materials are
potassium-40, uranium, and thorium
y involves measuring the bulk resistance between a surface electrode and the
downhole probe.
Single-point resistance
simply a record of the changes in hole diameter with depth. The
probe has three mechanical arms which are opened at the bottom of the well,
where they expand to the diameter of the borehole
Caliper Logging
Temperature Logging:
1 degree Fahrenheit per 100 feet of depth.
Determination of lithology, stratigraphic correlation, effective porosity, true
resistivity, water level, salinity, extent
of clay content, location of metals having very high conductivities (galena,
chalcopyrite, etc.); permeability, grain
size, extent of fluid saturation
Electrical
Resistivity
(ER)
Determination of lithology, stratigraphic correlation, extent of clay content,
permeability
Self-Potential
(SP)
Mineral exploration
lectro-magnetic (EM)
Determination of lithography, proportion of shales, stratigraphic correlation, detection of radioactive minerals,
delineation of non-radioactive materials
Radioactive
Gamma
(natural
gamma)
determination of lithology via a photoelectric measurement,
bulk density, total porosity, cavities,
location of water table, extent of
cement in borehole, construction
within existing borehole, (e.g., locates
casing and perforations)
GammaGamma
(formation
density logs)
Detector measures quantity of neutrons; determination of lithology
porosity, hydrogen content, water
level, moisture content, gas-bearing
zones
Neutron
Determination of heat flow, flow direction of fluids and gas (both vertically
and horizontally), abnormal radioactivity, zones of oxidation or reduction
Thermal
Seismic velocity (compressional wave)
seismic interpretation, generally, useful for correlation, total porosity, bulk
density, extent of bonding of cement
in casing, overpressured (abnormally
high fluid pressures) zones, permeability, secondary permeability. Newer
generation tools measure compressional, shear, and stonely waves.
Stonely waves are thought to be
inversely proportional to permeability.
Sonic are very valuable for identifying
potential gas zones through a phenomenon known as “cycle skipping”,
lithology, and desaturated zones
Sonic (acoustic)
Elastic-Wave
Propagation
Determination of density, porosity
Gravimetric
Determination of lithology, stratigraphic correlation, location of fractures,
extent of cement in borehole, casing
corrosion and borehole breakout, if
run in combination with a navigation
package
Diameter of borehole
Caliper
A measurement of
DC potential in the
borehole
Used to determine Rw and lithology,
and as an indicator of permeability
One of the first logging measurements
SP –
Spontaneous
Potential
Shallow measurements of resistivity that investigate the
resisitivity of the mudcake and the invaded zone. These tools are shallow measuring devices
Microresistivity
These tools are
generally symmetric resistivity devices with
one transmitter and pairs of receiver coils.
They typically have several depths of measurements that include 10, 20, 30, 60, 90
and 120 inches as determined by 50 percent
of the integrated radial factors and vertical
resolution capabilities to 1 foot. They are also
corrected for depth and speed by z-axis accelerometers.
Array Induction Tools
These tools respond to the water content in the formation
and investigate roughly 8, 12 and 17 centimeters into the formation mainly in
the invaded or flushed zone. They are very good tools for identifying the difference of heavy oil and fresh water and are excellent thin-bed devi
Dielectric Tools
NMR tools take a look at the fluids.
Protons are introduced to a magnetic field
and then an alternating current. From this
measurement porosity is calculated along
with moveable fluids and permeability
Nuclear Magnetic Resonance (NMR)
Tools
Two methods are used widely
in the petroleum industry to image formations. One is a sonic measurement that uses
a rotating transducer and the other is a
pad-type device that makes electrical measurements using several buttons. The tools
also contain a directional package for hole
deviation and azimuth measurements. These
tools are used to determine hole rugosity,
borehole breakout, fracture orientation, fracture identification, formation bed dip and bed thickness. The sonic type of imaging device is also used in cased holes for casing integrity and bonding.
Imaging
Samples of the formation are taken with sidewall coring guns
that generally take a one-inch by two-inch sample of the rock at various depths
using percussion cores that are injected into the formation by use of explosive
gun powder. These samples are then analyzed for porosity, permeability, lithology and more.
For harder, denser formations, a rotary sidewall coring tool is used that actually
drills through the formation with a small diamond-bit drill to obtain a sample
Sidewall Cores –
– Allows the measurement of formation pressure
at different depths and the mobility of fluids in the reservoir; it is used to obtain
samples of formation fluids and to determine pressure gradients. These tools
help identify oil, water and gas contacts in the reservoir. These tools can also be
adapted to run in cased wellbores by shooting a hole in the casing and cement
to connect with the formation
Wireline Formation Testing
These tools are used
after frac operations to identify where radioactive-tagged proppant is placed in the formation. A
spectral gamma ray tool is used to make this measurement. This method can also be used for acid
stimulation jobs and cement jobs.
TracerScan™ Surveys
Cement bond tools use sound
attenuation to determine bonding of cement to the
casing. It is important to have zonal isolation in oil
wells to keep from producing unwanted water. The
acoustic scanning tools used today for advanced
cement bonding also make a measurement of casing integrity by measuring inside diameter and
thickness of the steel casing
Cement Bond Logs
a two-dimensional stress system two perpendicular directions exist for which
the shear stress (τ) is zero. These directions are called
principal directions
one
set of layers or laminae are truncated
by overlying layers,
concave side of cross-bedding generally points toward the original upper
side.
Cross-bedding
symmetrical ripple
marks, the crests (tops) are sharper
than the troughs.
Ripple marks
Small, wave or tonguelike penetrations of a coarse clastic
material from above into a finer clastic
material below along minor surface
irregularities on a bedding plane.
possibly triggered by earthquakes.
develop along a contact of sand (now sandstone) overlying a clay (now
shale), but are rarely (if ever?) formed at the contact of clay overlying sand.
.Sole marks
Develop on the underside
of bedding units in sandstones and
siltstones. Characterized by a steep or
blunt bulbous or beaked up-current
end from which the structure flattens or flares out in the down-current
direction and merges with the bedding
plane. It is formed by the filling of a
flute
Flute casts
n the upright
section of folded rocks, the fracture
cleavage is generally steeper than the
bedding (a), but when the beds are
overturned the reverse is true
Fracture cleavage
Shelly invertebrates with intact living cavities, such as articulated brachiopods or gastropods, sometimes fill partially with sediment after
death. The unfilled part of the chamber later fills with calcite or other cement
and indicates the original top of the bed. This phenomenon is especially useful
in carbonate strata which typically lack other types of facing indicators.
Geopetal fabric
Shells of Invertebrate organisms or other solid objects lying with their
longer axes in the plane of stratification may be encrusted by bryozoans on the
upper side
Bryozoa
Sea urchins when found in large numbers are commonly oriented
with flat ventral (oral) side down and convex dorsal side up.
Echinoids.
Fold where the crest and
trough flare out at the AP. Broad hing
and limbs that converge away from the
hinge.
Fan fold
A fold with planar limbs
and a sharp angular hinge. A fracture
may separate the skeme from the rest
of the bed.
Kink folds
During the folding there
has been no “flowage,” even in
soft, incompetent beds. Fold has an
inter-limb angle between 70 and 120
degrees.
Open fold
During the folding there has been “flowage,” and the
incompetent beds thicken and thin.
Fold has an inter-limb angle between
30 and 70 degrees
Closed (tight) fold
Individual beds in these folds thicken
at their hinge and thin on their limbs.
Similar fold
A fold in which the thickness of all layers is consistent, resulting in individual folds that increase or
decrease in size upwards and downwards
Concentric (parallel or competent) fold
A fold that varies
noticeably in profile form in the various layers though which it pass
Disharmonic fold
A pattern of fold in which there is
thickening at the synclinal troughs and
thinning at the anticlinal crests. It is
formed by differential compaction on
an uneven basement surface
Supratenuous (compaction) fold:
A flexure
fold in which the mechanism of folding is slip along bedding planes or
along surfaces of foliation. There is
no change in thickness of individual
strata, and the resulting folds are parallel.
Flexural-slip folding
A fold model of
which the mechanism is shearing or
slipping along closely spaced planes
parallel to the fold’s axial surface. The
resultant structure is a similar fold
Shear (slip) folds:
A fold composed of relatively plastic rocks that have flowed
towards the synclinal trough. In this
type of deformation, there are no
apparent surfaces of slip. They occur
at great depth and usually in softer,
incompetent beds such as shale or
limestone
Flow folds
An uplift or anticilnal structure, either circular or elliptical in
outline, in which the rocks dip gently
away in all directions
Domes:
A low area (synclinal structure) in the crust in which sediments
have accumulated and the beds dip
radially toward a central point.
Basins
one that does not rupture at the surface. It is “buried” under the uppermost layers of rock in the crust
blind thrust fault
striae perpendicular to the strike
line).
90º
horizontal
striae)
0º
striae) represent mechanical striations that develop during faulting.
give the direction of slip on fault
planes. They are oriented by their pitch: the
angle between the strike line (a horizontal line
on the fault plane) and the striae
Slickenlines
found oriented at high angles to
the striae, and can be used to deduce the sense
of movement along a fault plane
result
from small fractures that develop at a high angle
to the direction of slip
along a fault plane
can be mineralized
represent cavities
where fluids can accumulate and minerals such as
quartz and calcite can form.
Steps
crushed and ground-up rock produced by friction
between the two sides when a fault moves.
fault gouge,
