Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
- Copper
- Molybdenum
- Gold
- Silver
|
Mining Method |
|
Production Start | ...  |
Mine Life | 40 years (as of Jan 1, 2022) |
The molybdenum plant at Spence produced and sold its first batch of molybdenum concentrate during Q4 FY2022. During May 2022, the new copper concentrator in Spence was inaugurated. The concentrator operates on desalinated seawater and is powered from renewable sources, and will allow the operation to be extended by 50 years. |
Source:
p. 42,349
Company | Interest | Ownership | Investor's Info |
BHP Group Ltd.
|
100 %
|
Indirect
|
|
Minera Spence S.A.
(operator)
|
100 %
|
Direct
|
|
Spence is owned by BHP: 100 percent.
Operator: BHP.
Contractors
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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.
Spence is 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.
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 an Open-cut mine.
Flow Sheet:
Summary:

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Reserves at June 3, 2022:
Cut-off criteria:
Mineral Resources: Oxide - 0.20%TCu; Low-grade Oxide - 0.20%TCu; Supergene Sulphide, Transitional Sulphide & Hypogene Sulphide - 0.20%TCu.
Ore Reserves: Oxide - 0.30%TCu; Supergene Sulphide - 0.20%TCu or - 0.30%TCu depending on processing, Transitional Sulphide & Hypogene Sulphide - 0.20%TCu.
Category | OreType | Tonnage | Commodity | Grade |
Proven & Probable
|
Oxide
|
17 Mt
|
Copper
|
0.67 %
|
Proven & Probable
|
Supergene sulphide
|
99 Mt
|
Copper
|
0.55 %
|
Proven & Probable
|
Transitional sulphide
|
16 Mt
|
Copper
|
0.59 %
|
Proven & Probable
|
Hypogene sulphide
|
1,410 Mt
|
Copper
|
0.45 %
|
Proven & Probable
|
Transitional sulphide
|
16 Mt
|
Molybdenum
|
90 ppm
|
Proven & Probable
|
Hypogene sulphide
|
1,410 Mt
|
Molybdenum
|
150 ppm
|
Total Resource
|
Oxide
|
20 Mt
|
Copper
|
0.65 %
|
Total Resource
|
Supergene sulphide
|
100 Mt
|
Copper
|
0.55 %
|
Total Resource
|
Transitional sulphide
|
16 Mt
|
Copper
|
0.59 %
|
Total Resource
|
Hypogene sulphide
|
2,340 Mt
|
Copper
|
0.43 %
|
Total Resource
|
Transitional sulphide
|
16 Mt
|
Molybdenum
|
90 ppm
|
Total Resource
|
Hypogene sulphide
|
2,340 Mt
|
Molybdenum
|
120 ppm
|
Type | Material | Diameter | Length | Description |
HME Type | Model | Quantity | Ref. Date |
Drill
|
.......................
|
.......................
|
Dec 6, 2021
|
Truck (haul)
|
.......................
|
.......................
|
Apr 29, 2022
|
Truck (haul)
|
|
.......................
|
Jun 17, 2022
|
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