Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Continuous
- Room-and-pillar
|
In August 2019, Mosaic indefinitely idled Colonsay, Saskatchewan mine. In the third quarter of 2021, the company restarted operations at Colonsay to offset a portion of the production lost by the early closure of K1 and K2.
At Colonsay, production was temporarily halted in December but is expected to restart in the first half of 2023. |
Source:
p. 44
Company | Interest | Ownership |
The Mosaic Company
|
100 %
|
Indirect
|
Mosaic Potash Colonsay ULC
(operator)
|
100 %
|
Direct
|
Colonsay Potash Facility is 100% owned by Mosaic Potash Colonsay ULC, a wholly-owned, indirect subsidiary of Mosaic.
Contractors
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Summary:
Extensive potash deposits are found in the southern half of the Province of Saskatchewan. The potash ore is contained in a predominantly rock salt formation known as the Prairie Evaporites. The Prairie Evaporites deposits are bounded by limestone formations and contain the potash beds. Three potash deposits of economic importance occur in Saskatchewan: the Esterhazy, Belle Plaine and Patience Lake members. The Patience Lake member is mined at Colonsay. The particular beds mined at Colonsay and Esterhazy have a mining height of 11 and 8 feet, respectively.
Mining Methods
- Continuous
- Room-and-pillar
Summary:
Colonsay utilizes shaft mining. Traditional potash shaft mining takes place underground at depths of over 1,000 meters where continuous mining machines cut out the ore face and load it onto conveyor belts. The ore is then crushed, moved to storage bins and hoisted to refineries above ground.
Mining at Colonsay is conducted within the upper portion of the Patience Lake Member using a room and pillar mining method.
Source:
Summary:

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Reserves at December 31, 2022:
No cut-off grade or value based on commodity price is used to estimate mineral resources and resources as the mining method used at Colonsay is not grade selective.
Category | Tonnage | Commodity | Grade |
Proven
|
101 Mt
|
K2O
|
25.3 %
|
Probable
|
163 Mt
|
K2O
|
27.2 %
|
Proven & Probable
|
264 Mt
|
K2O
|
26.5 %
|
Inferred
|
977 Mt
|
K2O
|
29 %
|
Corporate Filings & Presentations:
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