Source:
p. 26,182,236
Company | Interest | Ownership | Investor's Info |
BHP Group Ltd.
|
100 %
|
Indirect
|
|
Minera Spence S.A.
(operator)
|
100 %
|
Direct
|
|
BHP ownership: 100 percent.
Operator: BHP.
Summary:
The Spence porphyry copper deposit is related to three stocks of dacitic porphyries and tourmaline-bearing hydrothermal breccias, which were emplaced in andesitic volcanic rocks of the Upper Cretaceous–Lower Tertiary. Laser 40Ar/39Ar plateau ages in magmatic biotites of pre- and post-mineralization dacitic stocks show evidence that hypogene mineralization (chalcopyrite, pyrite, molybdenite, and lesser amounts of bornite and tennantite) occurred between 56 and 57 Ma.
Unconsolidated gravel deposits and a leach cap cover an oxidation blanket characterized by atacamite, chrysocolla, and minor brochantite, in which the Cu-hydroxychloride is by far the dominating mineral. Underlying the oxide zone is a well-developed chalcocite- and lesser covellite-bearing supergene enrichment blanket.
Representative samples from pit walls and drill cores were selected in order to cover most of the hypogene and supergene zones, including chalcopyrite from the hypogene-enriched sulfides and hypogene zones, chalcocite from the supergene-enriched sulfides and hypogene-enriched blankets, chrysocolla from the oxide blankets, and atacamite from the oxide zone within the host rocks and gravels and leach cap.
Summary:
Spence is Open-cut. Enriched and oxidised porphyry copper deposit containing in situ copper oxide mineralisation that overlies a near-horizontal sequence of supergene sulphides, transitional sulphides, and finally primary (hypogene) sulphide mineralisation.
Processing
- Crush-and-stack plant
- Flotation
- Heap leach
- Solvent Extraction & Electrowinning
Flow Sheet:
Summary:
Spence produces copper cathodes and, since December 2020, copper concentrate. Crushing facilities feed concentrator and leaching processes. 1 copper concentrator plant with 95 ktpd capacity (by-products: gold and silver), molybdenum plant and a 1,000 lps desalinated water plantunder a Build, Own, Operate, Transfer (BOOT) agreement. Dynamic leach pads, solvent extraction and electrowinning plant Nominal capacity of tank house: 200 ktpa copper cathode.
Recoveries & Grades:
Commodity | Parameter | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
Copper
|
Head Grade, %
| ......  | ......  | ......  | 1.13 | 1.14 | 1.33 | 1.21 |
Reserves at June 3, 2021:
Cut-off criteria:
Mineral Resources: Oxide - 0.30%TCu; Low-grade Oxide - 0.20%TCu; Supergene Sulphide, Transitional Sulphide & Hypogene Sulphide - 0.20%TCu.
Ore Reserves: Oxide - 0.30%TCu; Supergene Sulphide, Transitional Sulphide & Hypogene Sulphide - 0.20%TCu.
Category | OreType | Tonnage | Commodity | Grade |
Proven
|
Oxide
|
26 Mt
|
Copper
|
0.67 %
|
Proven
|
Supergene sulphide
|
104 Mt
|
Copper
|
0.59 %
|
Proven
|
Transitional sulphide
|
20 Mt
|
Copper
|
0.64 %
|
Proven
|
Hypogene sulphide
|
636 Mt
|
Copper
|
0.46 %
|
Proven
|
Transitional sulphide
|
20 Mt
|
Molybdenum
|
100 ppm
|
Proven
|
Hypogene sulphide
|
636 Mt
|
Molybdenum
|
180 ppm
|
Probable
|
Oxide
|
0.3 Mt
|
Copper
|
0.57 %
|
Probable
|
Supergene sulphide
|
7.8 Mt
|
Copper
|
0.41 %
|
Probable
|
Transitional sulphide
|
0.5 Mt
|
Copper
|
0.49 %
|
Probable
|
Hypogene sulphide
|
725 Mt
|
Copper
|
0.45 %
|
Probable
|
Transitional sulphide
|
0.5 Mt
|
Molybdenum
|
60 ppm
|
Probable
|
Hypogene sulphide
|
725 Mt
|
Molybdenum
|
130 ppm
|
Proven & Probable
|
Oxide
|
26 Mt
|
Copper
|
0.67 %
|
Proven & Probable
|
Supergene sulphide
|
112 Mt
|
Copper
|
0.58 %
|
Proven & Probable
|
Transitional sulphide
|
20 Mt
|
Copper
|
0.64 %
|
Proven & Probable
|
Hypogene sulphide
|
1,360 Mt
|
Copper
|
0.45 %
|
Proven & Probable
|
Transitional sulphide
|
20 Mt
|
Molybdenum
|
100 ppm
|
Proven & Probable
|
Hypogene sulphide
|
1,360 Mt
|
Molybdenum
|
150 ppm
|
Measured
|
Oxide
|
27 Mt
|
Copper
|
0.66 %
|
Measured
|
Low-grade oxide
|
0.6 Mt
|
Copper
|
0.26 %
|
Measured
|
Supergene sulphide
|
103 Mt
|
Copper
|
0.59 %
|
Measured
|
Transitional sulphide
|
20 Mt
|
Copper
|
0.64 %
|
Measured
|
Hypogene sulphide
|
636 Mt
|
Copper
|
0.46 %
|
Measured
|
Transitional sulphide
|
20 Mt
|
Molybdenum
|
100 ppm
|
Measured
|
Hypogene sulphide
|
636 Mt
|
Molybdenum
|
180 ppm
|
Indicated
|
Oxide
|
1.6 Mt
|
Copper
|
0.66 %
|
Indicated
|
Low-grade oxide
|
0.1 Mt
|
Copper
|
0.26 %
|
Indicated
|
Supergene sulphide
|
8.1 Mt
|
Copper
|
0.41 %
|
Indicated
|
Transitional sulphide
|
0.5 Mt
|
Copper
|
0.49 %
|
Indicated
|
Hypogene sulphide
|
773 Mt
|
Copper
|
0.45 %
|
Indicated
|
Transitional sulphide
|
0.5 Mt
|
Molybdenum
|
60 ppm
|
Indicated
|
Hypogene sulphide
|
773 Mt
|
Molybdenum
|
130 ppm
|
Inferred
|
Supergene sulphide
|
0.2 Mt
|
Copper
|
0.42 %
|
Inferred
|
Hypogene sulphide
|
981 Mt
|
Copper
|
0.39 %
|
Inferred
|
Hypogene sulphide
|
981 Mt
|
Molybdenum
|
90 ppm
|
Total Resource
|
Oxide
|
29 Mt
|
Copper
|
0.66 %
|
Total Resource
|
Low-grade oxide
|
0.7 Mt
|
Copper
|
0.26 %
|
Total Resource
|
Supergene sulphide
|
111 Mt
|
Copper
|
0.58 %
|
Total Resource
|
Transitional sulphide
|
21 Mt
|
Copper
|
0.64 %
|
Total Resource
|
Hypogene sulphide
|
2,390 Mt
|
Copper
|
0.43 %
|
Total Resource
|
Transitional sulphide
|
21 Mt
|
Molybdenum
|
100 ppm
|
Total Resource
|
Hypogene sulphide
|
2,390 Mt
|
Molybdenum
|
120 ppm
|
HME Type | Model | Quantity | Ref. Date |
Drill
|
.......................
|
.......................
|
Dec 6, 2021
|
Truck (haul)
|
.......................
|
.......................
|
Apr 29, 2022
|
Truck (haul)
|
|
.......................
|
Apr 29, 2022
|
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