The Elk Valley Coal Field
The major coalfields of British Columbia are grouped into the Rocky Mountains, Insular
and Intermontane coalfields. The insular belt includes the coalfields and deposits on
Vancouver Island and small deposits on the Queen Charlotte Islands to the north. The
Intermontane Belt includes a number of coalfields and deposits through the centre of the
province. The Rocky Mountain Belt (where most of the mines are located) includes the
important coalfield areas in the southeast (East Kootenay Coalfield) and the northeast of
the province (Peace River Coalfield).
East Kootenay Coalfields
The East Kootenay Coalfields comprise three separate fields extending from the
Montana border northward and known respectively as Flathead, Crowsnest, and Elk
Valley coalfields. These are the most important coalfields of the province, having
produced, since 1898, over
500 million tonnes of mainly
metallurgical coal.
All three fields are underlain
by the Jura-Cretaceous
Kootenay Group, which
contains the 100 to 700
metres thick coal-bearing
Mist Mountain Formation.
Coal seams are found
throughout the formation
though the thicker seams
occur lower in the section.
The formation contains from 4 to over 30
seams, which make up from 8% to 12% of
the thickness of the formation. Cumulative
coal thickness ranges up to over 70 metres.
The area has experienced moderate to
intense folding and thrust faulting, which
has caused repetitions and structural
thickening of seams. Rank varies from low
to high-volatile A bituminous though most of
the coal is medium-volatile bituminous and of metallurgical grade.
All the coal mined from the five open-pit mines in the East Kootenay coalfields is
exported.
In the south, in the Crowsnest Coalfield, Fording Coal Limited owns and operates Coal
Mountain Operations which in 2001 mined 2.4 million tonnes of high-volatile A
bituminous weak coking coal. Most of the coal comes from a single seam near the base
of the Mist Mountain Formation. The Elkview Mine (formally the Balmer Mine) is owned
and operated by Teck-Cominco Corporation and is located in the northern end of
Crowsnest Coalfield. In 2001 the mine produced 5.6 million tonnes of medium-volatile
hard coking coal, mainly from the bottom four seams in the Mist Mountain Formation.
There are three mines in the Elk
Valley Coalfield. In the south the
Line Creek Mine owned by Luscar
Limited and operated by Line
Creek Resources Limited, in 1999
sold about 2.8 million tonnes of
which about 0.5 million tonnes
was thermal coal. The
metallurgical coal is a mediumvolatile hard coking coal. In the
northern part of the Elk Valley
coalfield, Fording Coal Limited
owns and operates the Greenhills
Mine which produced 4.7 million
tonnes of clean coal in 2001 and
the Fording River mine (9.4
million tonnes clean coal
production in 2001). Both these
mines produced coal from a large
number of seams through a thick
Mist Mountain section and
consequently sell medium and
high-volatile coking coal.
Mine
Production in
2001 (millions
of tones)
Coal Mountain
2.4
Elk View
5.6
Line Creek*
2.8
Greenhills
4.7
Fording Creek
9.4
District total
24.9
*1999 production
Excerpted from and modified by Steven Earle (2006) from:
Coal in British Columbia
Barry Ryan PhD, P.Geo,
Coal and Coalbed Methane Geologist
New Ventures Branch,
Ministry of Energy and Mines
(http://www.em.gov.bc.ca/Mining/GeolSurv/coal/coalinbc/coal_bc.htm#Coalfields%20of%20British%20Columbia)
Stratigraphy and structural geology in the Elk Valley Coalfield
The basal unit of the Kootenay Group is the Morrissey Formation. The Morrissey is a resistant
sandstone unit consisting of two members and ranging in thickness from 20 to 80 metres
(Gibson, 1985). The upper member, the Moose Mountain member, is a distinctive marker unit
consisting of medium-grained sandstone, which is utilized in all surface and subsurface studies of
the Kootenay to demarcate the base of coal occurrences. Within the study area the Moose
Mountain member was observed to be more variable than normal. For example, it includes one
or more carbonaceous partings in the area between Weary Ridge and Mount Tuxford, and at two
localities south of Aldridge Creek it was observed to include an unusual light grey to white
weathering, quartzose facies. The trace of the Morrissey Formation on the east limb of the
Alexander Creek syncline is plotted with moderate confidence on Sheet 2.
The Mist Mountain Formation contains essentially all the coals of economic interest in
southeastern British Columbia. Its thickness in the study area ranges between 450 and 550
metres. Coal forms between 8 and 12 per cent of the total thickness of the formation at most
locations. Individual seams in the study area range from less than 1 to greater than 10 metres in
thickness. In the area covered by Map Sheet 2, a section 550.0 metres thick comprising the
complete Mist Mountain Formation was measured along the north ridge of Mount Tuxford. It
hosts 39.5 metres of coal, representing only 7.2 per cent of the total thickness of the formation.
However, some 50.6 metres of the section are covered, a portion of which could contain coal.
The precise identification of the contact of the Mist Mountain Formation with the overlying Elk
Formation in southeastern British Columbia is generally difficult. The Elk is a coarser grained
facies than the Mist Mountain and it generally lacks thick coal seams and contains unusual
sapropelic coals known as "needle coals". The thickness of the Elk Formation in the study area is
inferred to range between 350 and 450 metres. The Elk - Mist Mountain contact on Sheet 2 is
located just below the peak of Mount Tuxford. It overlies a 2-metre-thick coal seam and is at the
base of a thick sandstone sequence. This position also corresponds with a change in colour; the
Elk Formation sandstones weather to a distinctive yellow or orange-brown colour compared with
the predominantly grey weathering colour of the Mist Mountain Formation sandstones. A section
of Elk Formation comprising the lowest 178 metres was measured. The lower two-thirds of the
section consists of several stacked channel - sandstone units separated by thin, recessive, finer
grained intervals, including a 1.0- metre thick coal seam. The upper third is a recessive interval
including coal seams 1.0 and 1.6 metres thick. The section is overlain by a prominent cliffforming sandstone that marks the base of another sequence of stacked sandstone units.
The Kootenay Group is unconformably (?) overlain by the Lower Cretaceous Blairmore Group.
The basal unit of the Blairmore Group is the Cadomin Formation, a distinctive cliff-forming
conglomerate unit.
The study area lies in the Front Ranges of the Rocky Mountains and is part of the Lewis thrust
sheet. The major structure in the coalfield is the Alexander Creek syncline, which extends
throughout its entire 100-kilometre length. The northern extension of the Greenhills syncline,
which is west of the Alexander Creek syncline, also influences the extreme southern end of the
study area.
The Alexander Creek syncline is overturned in the central part of the study area, and open
elsewhere. It generally plunges to the north.
The Bourgeau thrust fault, which marks the western boundary of the surface exposures of the
Lewis thrust sheet, forms the western boundary of the Mist Mountain Formation the Elk valley
coalfield in the study area. The relative footwall stratigraphic position of the fault varies along its
trace from the Fernie Formation to uppermost Kootenay. At the north end of the study area it is
offset 2 kilometres to the northeast by a transverse fault.
Minor structures associated with the Bourgeau thrust are not generally observable because of
poor exposure. The area known as "Coal Creek" on the west limb of the Alexander Creek
syncline is one exception. See Sheet 3 for more detail. The complex folding in the northern part
of Map Sheet 2 is interpreted to be caused by the Bourgeau thrust ramping to the east at this
point.
Small-scale folds affect the Mist Mountain Formation strata in three general areas: the extreme
south end of the study area (see Sheet 1), the lower west-facing slopes of Mount Tuxford (see
Sheet 2), and the small eastward-flowing creeks north of Cadorna Creek (see Sheets 6 and 7).
These are mainly interpreted as minor folds associated with the Alexander Creek syncline, and,
with few exceptions, are not attributed directly to thrusting.
In contrast with the south half of the coalfield (see Grieve and Fraser, 1985), thrust faults within
the Kootenay Group are not a major feature of the study area. On Henrietta Ridge at the extreme
south end of the study area, however, two thrust faults are observed (see Sheet 1). One causes
a repeat of the Morrissey Formation and lowermost part of the Mist Mountain Formation; the other
occurs higher in the Mist Mountain Formation and is exposed on the south-facing slope of the
ridge. A third thrust fault is inferred to occur in the east limb through part of the north end of the
study area, based on sporadic occurrences of deformed strata (see Sheet 6 for example).
Late-stage, crosscutting normal faults are present in the Mount Tuxford and Mount Veits areas.
These appear to follow prominent joint orientations and have resulted in mass wasting of the
Morrissey Formation, forming both topographic steps and landslide blocks. A large landslide
block of Morrissey Formation occurs on Weary Ridge (see Sheet 4). A set of two normal faults is
shown at the north end of Mount Tuxford on Map Sheet 2. A combined 16 metres of normal
displacement is estimated. A system of three faults, striking to the north and dipping steeply east,
occurs approximately 400 metres due east of the peak of Mount Tuxford. The faults show a
combined 8 metres of reverse displacement.
Excerpted from: Preliminary Map No. 68
Geology of the Elk Valley Coalfield (North Half)
(Henrietta Creek to Elk Lakes)
by R.J. Morris, D.A. Grieve, 1990
http://www.em.gov.bc.ca/Mining/Geolsurv/Publications/PrelimMaps/PM68/toc.htm