Osk
Stream Sediment Samples
Lithological Contact
449000
447000
AL-13-16
453000
AL-13-18
AL-13-18B
Thrust Fault
Normal Fault
6252000
River
Elevation Contour
The Aley Carbonatite (290 km north of Prince George, BC; inset map) outcrops
over a 3-3.5 km diameter area. Measured+indicated resources are 286 million
tonnes at 0.37% Nb2O5 (Taseko Mines Limited, 2013). The Aley Carbonatite
intruded into platformal carbonate and siliciclastic rocks of the Kechika Formation,
Skoki Formation and Road River Group. Twelve stream-sediment samples
(locations denoted by red circles) were collected from the stream draining the Aley
carbonatite. From Mackay et al. 2015; modified after Mäder (1986), Massey et al.
(2005), McLeish (2013) and Mackay and Simandl (2014).
1000
500
0
1500
1000
500
0
10000
5000
0
100
750
500
250
0
0
Tailings
25
m
m
>4
m
m
4
2-
m
m
m
m
m
5μ 63μ
0μ 50μ
2
0
<
1
2
5
35μm 506
2
0
1
2
50
m
m
2
1-
m
-1
m
m
>4
Sieve Opening Size
m
m
4
2-
m
m
m
m
m
5μ 63μ
0μ 50μ
2
0
<
1
2
5
35μm 506
2
0
1
2
50
m
m
2
1-
m
-1
Water flow
3
Mag
Ap
Stage 1 (previous work) involved characterising the Aley
carbonatite, stream-sediment sample collection, and
orientation survey. This involved chemical analyses of the
sediments and selection of an optimal size fraction for indicator
mineral studies (Luck and Simandl 2014; Mackay and Simandl
2014).
Pcl
Cmb
Agg
Lit
a
0.5 mm
b
0.25 mm
0.25 mm
c
d
a) Fresh (unweathered)
euhedral, dark brown and b)
subhedral, strongly weathered
pyrochlore grains from stream
sediments sampled directly over
the deposit (sample AL-13-04). c)
Subhedral, slightly weathered
and d) strongly weathered
pyrochlore grains from
downstream (8.8km; sample AL13-16) of the Aley carbonatite.
a
b
Cmb
100μm
100μm
c
Ap
d
Mnz
Dol
Pcl
100μm
e
Rim
f
Cl
100μm
Mag
Pcl
Ap
Stage 3 (proceeding concurrently with stage 2) will address
customization of microscopic, SEM, QEMSCAN, and electron
microprobe methods in advanced mineralogical studies.
Hem
0.25 mm
0.25 mm
100μm
100μm
a) Euhedral columbite(Fe) partially surrounded
by apatite (polished grain
mount in plane polarized
light; ppl). b) The
columbite-(Fe) grain
shows irregular texture
characteristic for the Aley
carbonatite (back scatter
electron; BSE).
Composite grains
containing two or more
mineral phases are
common.
c) Euhedral pyrochlore
grain (ppl). d) The
pyrochlore is highly
fractured and contains
dolomite (Dol) and minor
monazite (Mnz)
inclusions (BSE). The
grain also has a minor
weathered rim of Nb and
Fe oxide material.
e) An anhedral apatite
grain (ppl image) f) with
subhedral pyrochlore
and hematite inclusions.
The apatite has an
alteration (weathered)
rim of hematite (Hem),
magnetite and minor
chlorite (Cl) (BSE).
Starting Mass of Magnetite in Synthtic Standards (g)
Limited exploration budgets and deposit andcommodity specific
exploration necessitates a more focussed, customized
approach.
( Left ) Mozley C800 heavy
mineral concentrate (sample AL13-16) containing apatite (Ap),
pyrochlore (Pcl), columbite-(Fe)
(Cmb), and magnetite (Mag).
Lithic fragments (Lit), and grain
aggregates (Agg) are also
present. Pyrochlore is identified
by its distinctive octahedral
crystal habit. Optical
identification can be difficult in
highly weathered grains. A
magnet can be used to separate
magnetite from columbite-(Fe)
and other non-magnetic
minerals.
Mass of Magnetite in Mozley C800 Concentrates (g)
Nb in Raw Samples (ppm)
8000
AL-13-02
6000
AL-13-16
AL-13-08
AL-13-10
AL-13-18
4000
AL-13-18B
AL-13-01
AL-13-07
AL-13-09
0
Tailings
0
5000
10000
Concentrate
15000
20000
25000
AL-13-08
7000
AL-13-04
AL-13-05
AL-13-06
6000
AL-13-02
5000
AL-13-10
AL-13-16
4000
3000
2000
AL-13-01
AL-13-18
AL-13-18B
AL-13-07
AL-13-09
1000
0
5000
0
10000
15000
20000
25000
LREE (Σ La, Ce, Pr, Nd) in Concentrate (ppm)
d 180
R² = 0.77
AL-13-04
AL-13-06
140
AL-13-08
120
AL-13-16
100
AL-13-01
80
R² = 0.23
160
AL-13-05
160
AL-13-18B
AL-13-02
AL-13-10
AL-13-18
60
AL-13-08
AL-13-04
140
AL-13-10
AL-13-05
100
AL-13-18B
80
AL-13-16
AL-13-01
AL-13-18
60
AL-13-09
AL-13-07
AL-13-09
AL-13-02
AL-13-06
120
40
AL-13-07
40
20
20
0
0
0
(Above) Most stream-sediment samples (~75g) show 24.7-32.0% of
material retained in concentrate, consistent with the natural sample used
during optimization. Sample AL-13-09 (sampled upstream of the
carbonatite) shows noticeably lower proportions of retained concentrate
(3.8%). (Below) Mozley C800 concentrates show large average increases
in the concentration of Nb (4.3 times), Ta (3.1 times), and LREE (3.1 times)
relative to raw (unprocessed) samples. Samples are ordered by their
geographic location from west to east (see map). The decreasing
carbonatite signature with increasing distance downstream is preserved.
From Mackay et al. 2015.
R² = 0.80
8000
30000
c 200
180
Sample number
9000
Nb in Concentrate (ppm)
Middlings
50
100
150
200
250
Y in Concentrate (ppm)
300
350
400
0
50
100
150
200
250
300
350
400
Ta in Concentrate (ppm)
(Above) Excellent correlation, based on high coefficients of determination
(R2), of (a) Nb (R2=0.94), (b) LREE (R2=0.80), Fe (R2=0.86) and moderate
correlation of (c) Y (R2=0.77) in raw samples and Mozley C800
concentrates indicates consistent and effective concentration of
pyrochlore, columbite-(Fe), magnetite, monazite, and REE2
fluorcarbonates. The low coefficient of determination (d; R =0.23)
between Ta concentrations in raw samples and Mozley C800 concentrates
is likely due to concentrations near the detection limit. From Mackay et al.
2015.
Conclusions
- Mozley C800 Laboratory Mineral Separator is a compact,
simple instrument with operating conditions that can be
optimized for drainage-, deposit-, or commodity-specific
conditions.
Optimization of Operating Conditions
Synthetic standards (75g)
were used to test
operating parameters.
They were made
predominantly of quartz
with 0.33 to 10 wt. %
each of magnetite,
garnet, and fluorite. The
excellent correlation
2
(R =0.98) between
magnetite in synthetic
standards and in Mozley
C800 concentrates
indicates consistent
concentration. Magnetite
concentration increased
by 5.5 to 228.2 times.
From Mackay et al. 2015.
AL-13-05
AL-13-06
2000
Sieve Opening Size
Potential indicator minerals for carbonatite-hosted specialty metal desposits include pyrochlore (4.20-6.40 g/cm ), columbite-(Fe) (5.30-7.30 g/cm ), fersmite (4.69-4.79
3
3
3
3
g/cm ), monazite (4.80-5.50 g/cm ) and REE-fluorocarbonates such as bastnaesite (4.95-5.00 g/cm ) and synchysite (3.90-4.15 g/cm ). These minerals have similar or
3
higher densities than magnetite (5.10-5.20 g/cm ) in the synthetic standards used for initial optimization of Mozley C800 operating conditions.
Mag
Concentrate
0
Potential Indicator Minerals
Project Outline
Middlings
AL-13-04
LREE (Σ La, Ce, Pr, Nd) in Raw Samples (ppm)
Water
flow
50
3
Stage 2 (current study) involves evaluation of inexpensive and
rapid methods to produce heavy-mineral concentrates for
specialty metal-targeted exploration. An initial assessment of
the Mozley C800 Laboratory Mineral Separator (referred to from
here on as Mozley C800) is presented using synthetic standards
(prepared for this purpose) and stream-sediments collected
from the Aley carbonatite drainage area. Minerals with high
densities and constituent Nb, Ta, and light rare earth elements
(LREE; La, Ce, Pr, and Nd) were selected as potential indicator
mineral candidates.
Wash Water Pipe
R² = 0.94
Ta in Raw Samples (ppm)
AL-13-10
(Left) A sample being poured
onto a Mozley C800. Water is
supplied to the v-profile tray by
the wash water pipe and the
irrigation pipes. Arrows denote
the direction of water flow.
Duration of processing varied
during operating condition
optimization to suit deposit
characteristics and sample size.
Other operating parameters
were kept constant for all
samples. From Mackay et al.
2015.
(Below) Separated concentrate
(high density), middlings
(medium density), and tailings
(low density). Concentrate
narrows to where the middlings
start. Separation of middlings
from tailings is marked by a
decrease in the spatial density
of grains. From Mackay et al.
2015.
b
10000
Nb (ppm)
Al
ek
Cre
Results and Discussion
Ore Systems
a 12000
Y in Raw Samples (ppm)
6254000
1500
1000
500
0
Processing Procedure
Propor on of material retained
AL-13-08
3000
2000
1000
0
750
500
250
0
Also available as British Columbia Geological Survey Geofile 2015-07
Mackay, D.A.R., Simandl, G.J., Grcic, B., Luck, P., Li, C, Ma, W., Redfearn, M., and Gravel, J. 2015.
Assessment of Mozley C800 laboratory mineral separator for specialty metal indicator mineral
exploration: Aley carbonatite, British Columbia, Canada. British Columbia Ministry of Energy and
Mines, British Columbia Geological Survey, Geofile 2015-07.
4
TG
Natural Resources
Canada
Ressources naturelles
Canada
4
- Mozley C800 increased concentrations of Nb (average factor
of 4.3), Ta (average factor of 3.1), and LREE (average factor
of 3.1) from stream-sediment samples.
350
- Pyrochlore, columbite-Fe, monazite and REE-bearing
fluorocarbonates were consistently concentrated.
300
Ta (ppm)
AL-13-09
ORI
AL-13-01
3
250
200
Raw
- Based on chemical analyses, a predictable relationship
between indicator mineral counts in raw stream-sediment
samples and concentrates should be expected.
Tailings
150
Concentrate
100
50
- These findings justify stage 3 of this project which involves
microscopic, SEM (QEMSCAN), and electron microprobe
methodology to reduce or eliminate the need for handpicking indicator minerals.
0
25000
Tailings
Middlings
Concentrate
Duration of processing by Mozley C800 (min)
The proportion of
concentrate for five
identical sub-samples
(~75g) of AL-13-16
decreased with
increasing processing
time. All other parameters
were kept constant. The
15 minute time interval
was selected for the
remaining samples; this
time is a compromise
which ensures adequate
concentration of heavy
minerals, minimizing loss
to tailings. From Mackay
et al. 2015.
Acknowledgements:
LREE (ΣLa, Ce, Pr, Nd) (ppm)
AL-13-02
Osk
CmOK
6256000
Ce (ppm)
AL-13-04
AL-13-05
AL-13-06
AL-13-07
Pr (ppm)
CmOK
1000
Nd (ppm)
Ospika Diatreme
CmOK
2000
0
USA
400
0
Ba (ppm)
km
125
La (ppm)
Aley Carbonatite
ORI
Vancouver
250
ORI
Kamloops
0
3
Proportion of material retained
- The results of this study will form the basis
to optimize indicator mineral methodologies
to explore for carbonatite-hosted specialty
metal deposits world-wide.
Osk
British
Columbia
Pacific
Ocean
Lower to Middle Ordovician Skoki Formation.
Dolomite carbonate rocks.
Cambiran-Ordovician Kechika Formation.
CmOK argillaceous limestone, calcareous siltstone, and
dolostone.
- Evaluate the advantages of automated
methods (QEMSCAN) over hand picking for
advanced mineralogical studies.
0
6258000
Prince George
AL-13-18
100
Sr (ppm)
Lower to Upper Ordovician-Silurian Road River
Group. Cherty dolostone, shale, argillaceous
limestone, and rare quartzite and quartz pebble
conglomerate
Ordovician
Osk
ORI
Alberta
Ordovician and Silurian
ORI
CmOK
Aley Carbonatite
Complex
Aley Carbonatite
Osk
200
AL-13-02
0
Y (ppm)
Alaska
Nb (ppm)
Ospika Diatreme
Massive Carbonatite Related Fenitization
3
Concentration of potential
carbonatite pathfinder
elements for each size
fraction of stream-sediment
samples from the Aley area.
The 125-250μm size
fraction was selected for
stage 2 and 3 geochemical
and indicator mineral
studies based on the
distribution of material in the
different size fractions and
elemental concentrations
(Nb, Ta, and LREE; La, Ce,
Pr, Nd). Time permitting, the
63-125μm and 250-500μm
size fractions would also be
worthwhile for testing. From
Mackay et al. 2015;
modified from Mackay and
Simandl 2014.
5000
P (ppm)
Yukon
10000
Ta (ppm)
Northwest
Territories
Cambrian and Ordovician
- Assess heavy mineral separation by Mozley
C800 Laboratory Mineral Separator with an
emphasis on recovering Nb-bearing
(pyrochlore and columbite-[Fe]) and rare
earth element (REE)-bearing (monazite and
REE-fluorocarbonates) minerals.
Stream Sediment Orientation Survey
U (ppm)
geochemical methodologies to explore for
poorly exposed specialty metal deposits in
the Canadian Cordillera.
University of Victoria, School of Earth and Ocean Sciences, Victoria, BC
2
British Columbia Ministry of Energy and Mines, Victoria, BC
3
Bureau Veritas Canada Ltd., Inspectorate Metallurgical Division, Richmond, BC
4
Bureau Veritas Canada Ltd., Upstream Minerals Group, Vancouver, BC
REE-Bearing Carbonatite Dykes
- To refine customized indicator mineral and
2
1
Study Area, Local Geology,
and Stream Sediment Sample Locations
Aley Carbonatite and Intrusive Rocks
3
Irrigation Pipes
University
of Victoria
Th (ppm)
Main Objectives:
1, 2
D.A.R. Mackay , G.J. Simandl , B. Grcic , P. Luck , C. Li , W. Ma , M. Redfearn , and J. Gravel
Size Fraction
(wt. %)
Ministry of
Energy and Mines
1
455000
GICA L S
V
R
U
Assessment of Mozley C800 laboratory mineral separator for specialty metal indicator mineral exploration:
Aley carbonatite, British Columbia, Canada
451000
LO
EY
BR
B
IA
GE
O
I
C OLU
H
S
M
I
T
This project received funding and support from Targeted Geoscience Initiative 4 (2010-2015), a Natural Resources
Canada program carried out under the auspices of the Geological Survey of Canada. Inspectorate Exploration & Mining
Services Ltd. and ACME Analytical Laboratories are thanked for their generous support of this project. Logistical and
helicopter support by Taseko Mines Limited and the scholarship from Geoscience BC to the first author are also greatly
appreciated. Pearce Luck (British Columbia Geological Survey) and Cheng Li (Bureau Veritas Canada Ltd.,
Inspectorate Metallurgical Division) are thanked for their assistance and expertise during laboratory work.
20000
15000
References:
10000
5000
0
Sample ID
Mackay, D.A.R. and Simandl, G.J. 2014. Portable X-ray fl uorescence to optimize stream sediment chemistry and
indicator mineral surveys, case 1: Carbonatite-hosted Nb deposits, Aley carbonatite, British Columbia, Canada; In:
Geological Fieldwork 2013, British Columbia Ministry of Energy and Mines, British Columbia Geological Survey
Paper 2014-1, pp. 183-194.
Mackay, D.A.R., Simandl, G.J., Grcic, B., Li, C., Luck, P., Redfearn, M. and Gravel, J., 2015. Evaluation of Mozley C800
laboratory mineral separator for heavy mineral concentration of stream sediments in exploration for carbonatiterelated specialty metal deposits: case study at the Aley carbonatite, British Columbia (NTS 094B); In: Geoscience
BC Summary of Activities 2014, Geoscience BC, Report 2015-1, p. 111-122.
Mäder, U. K., 1986. The Aley Carbonatite Complex. Master of Science thesis, University of British Columbia, 176 p.
Massey, J.W.H., McIntyre, D.G., Dejardins, P.J., and Cooney, R.T., 2005. Digital geology map of British Columbia. British
Columbia Ministry of Energy, Mines and Petroleum Resources, British Columbia Geological Survey Open File
2005-2, DVD.
McLeish, D.F., 2013. Structure, stratigraphy, and U-Pb ziron-titanite geochronology of the Aley carbonatite complex,
Northeast British Columbia: Evidence for Antler-aged orogenesis in the foreland belt of the Canadian cordillera.
Master of Science thesis, University of Victoria, 131 p.