Metallurgical Testwork at Detour Lake, Ontario
(Overall target gold recoveries of 91% to 95% are expected)
Detour Gold Corporation (TSX: DGC) ("Detour Gold" or the
"Company") today announces the first results of metallurgical testwork
on samples from the Detour Lake deposit which as of December 2007
contained an open pit resource of 4.8 million ounces in the measured and
indicated categories (89.9 million tonnes grading 1.67 g/t gold) and
3.0 million ounces in the inferred category (63.2 million tonnes grading
1.49 g/t gold), using a gold price of US$575/oz (equivalent to a
cut-off grade of 0.64 g/t gold and capped at 20 g/t gold) (refer to
press release December 11, 2007).
Composite samples were prepared from assay rejects and drill core (HQ)
at SGS Mineral Services in Lakefield, Ontario representing the full
suite of geological rock types taken laterally and vertically throughout
the current mineral resource.
Initial testwork results indicate excellent gold recoveries, ranging
from 91% to 95%, using a standard gravity/cyanidation/carbon-in-pulp
circuit (refer to table on page 2). Mineralogical examinations have
confirmed that a large portion of the contained gold is present as free
gold particles. High gravity recoveries in the range of 32% to 53% are
being achieved in the test program. Reagent consumptions (both cyanide
and lime) are low, being less than 0.6 kg/t. Testwork also indicates
that a very low tail grade (non-recoverable gold which goes to the
tailings) of 0.08 to 0.10 g/t gold is achievable.
With these very positive test results, the Company anticipates that the
future operation would realistically be able to recover between 30% to
45% of the gold by gravity methods followed by cyanidation which would
recover over 90% of the remaining gold in the circuit to give a combined
circuit recovery target in the range of 91% to 95%.
Further metallurgical and comminution work are ongoing and the final
process design flowsheet for the feasibility study is expected in the
coming months.
Gerald Panneton, President and CEO of Detour Gold stated: "We are
extremely satisfied with the overall recoveries, which indicate a very
simple metallurgical flowsheet. Additional testwork in the coming
months will define the optimal development route (throughput and
capacity) so we can proceed with ordering the long-lead items such as
the grinding mills by mid-year. We are on schedule to complete an
updated mineral resource estimate by the end of June and a feasibility
study by the end of 2008."
The metallurgical testwork is under the supervision of Melis Engineering
Ltd. of Saskatoon, Saskatchewan. The technical contents of this release
have been reviewed by Lawrence Melis, P.Eng., of Melis Engineering
Ltd., a Qualified Person pursuant to NI 43-101.
| Preliminary Metallurgical
Results Averaged on Basis of Rock Blend 1,2 |
|
Major
Rock
Type |
% of Rock Type in Deposit
|
Specific
Gravity |
Calc.
Head
Grade
(g/t) |
Gravity
Tail
Grade
(g/t) |
Gravity
Recovery
(%) |
Cyanide
Recovery
(%) |
Residue
Grade
(g/t) |
Gravity
+ Cyanide
Recovery
(%) |
| MF |
46.8 |
2.86 |
1.95 |
0.97 |
50.3 |
91.4 |
0.09 |
95.7 |
| KMF |
13.2 |
2.93 |
1.44 |
0.80 |
44.4 |
pending |
pending |
pending |
| PF |
15.4 |
2.88 |
1.22 |
0.65 |
52.9 |
90.7 |
0.08 |
95.6 |
| KPF |
11.6 |
2.89 |
1.61 |
0.87 |
45.8 |
88.4 |
0.10 |
93.7 |
| TC |
5.5 |
2.86 |
0.42 |
0.29 |
31.7 |
93.2 |
0.03 |
95.4 |
| CG |
4.5 |
2.85 |
0.53 |
0.36 |
32.2 |
86.5 |
0.05 |
90.8 |
| Total/Avg |
97.0 |
2.88 |
1.57 |
0.80 |
47.5 |
90.7 |
0.08 |
95.1 |
(1) MF (mafic flow), KMF (potassically altered mafic flow),
PF (pillow flow), and KPF (potassically altered pillow flow) make up 87%
of the current mineral resource while the TC (talc schist) and CG
(chloritic greenstone) make up another 10%. The CBPF (carbonatized
pillow flow) and CH (chert) make up only 2.3% and as such are excluded
from the table herein.
(2) A total of approximately 2,300 samples of assay
rejects representing seven of the eight rock types (not including CG)
were sent to Lakefield for sample preparation and metallurgical testing.
Since the sample availability for the four minor rock types (CBPF, CH,
TC and CG) was limited, separate drill core samples (whole core) of
these rock types were received from the site for use in metallurgical
testing.
For further information, please contact:
Gerald Panneton, President and CEO
Tel: (416) 304.0800
Laurie Gaborit, Director Investor Relations
Tel: (416) 304.0581
Detour Gold Corporation, Royal Bank Plaza, North Tower, 200 Bay Street,
Suite 2040, Toronto, Ontario M5J 2J1
|