Summary:
The Belle Plaine property is underlain by the Esterhazy, Belle Plaine and Patience Lake Members. The mineable potash mineralization at Belle Plaine occurs in the three major potash bearing members, all of which are included in the solution mining.
The potash mined at Belle Plaine is a mixture of halite and sylvite and in some parts of the Mining Area,small amounts of carnallite. There are a number of clay-rich zones that are not recovered in the solution mining process that recovers a concentrate from a portion of the minerals rather than the entire bed.
There are distinct features that are correlated between core and geophysical logging and applied to indicate relative ore quality. The key characteristics that are interpreted using remote data include KCl grade, bedding identification, and carnallite presence. The potash deposit at Belle Plaine is uniform and laterally continuous. When properly calibrated, the gamma response can be converted to indicate the amount of potash in the geological unit as %KCl.The neutron-density log is used to indicate the presence of carnallite. These correlations arc possible based on understanding from examination of core.
The three mineable potash-bearing members underlying the Belle Plaine property are, in ascending stratigraphic order, the Esterhazy Member, the Belle Plaine Member and the Patience Lake Member. The White Bear Formation marker beds occur between the Belle Plaine and Esterhazy Members.
Mineralization
Potash mineralization contains sylvinite; a mixture of the iron oxide-stained halite, sylvite and locally, carnallite. When present interstitially or as massive pods, carnallite can deteriorate rapidly or be preferentially dissolved. The color of the potash can vary from light orange to deep red rimmed crystals. The mineralization can be locally bedded or massive. The halite and sylvite crystals can range from small to more typically coarse to large. This can be attributed to the conditions during deposition as there has been no alteration.
Carnallite is considered an impurity in solution mining and can result in dilution of the potash grade. The mineralogy of carnallite results in liberation of magnesium into the brine that is not removed through processing. Because the magnesium remains in suspension, there is reduced carrying capacity for KCl.
Three potash deposits of economic importance occur in Saskatchewan: the Esterhazy, Belle Plaine and Patience Lake Members. The Belle Plaine Potash Facility is a solution mine that recovers potash from each of the Estcrhazy, Belle Plaine and Patience Lake Members. The following is a summary of the key stratigraphic units for the Belle Plaine Potash Facility:
• Patience Lake Member: The uppermost member of the Prairie Evaporite Formation with potash production potential. Between the top of the Prairie Evaporite Formation and the top of the Patience Lake Member is a 0 to 45 ft. (0 to 14 tn) thick unit of halite with clay bands called the salt back. The sylvite-rich horizons within the Patience Lake Member arc mined using conventional underground mining techniques in the Saskatoon. Saskatchewan area and by solution mining techniques at Belle Plaine.
• Belle Plaine Member: The Belle Plaine Member underlies the Patience Lake Member and is separated from it by a zone of low grade sylvinitc. The Belle Plaine Member is mined using solution mining techniques at Belle Plaine.
• Esterhazy Member: The Esterhazy Member is separated from the Belle Plaine Member by the White Bear Marker Beds, a sequence of clay scams, low-grade sylvinitc, and halite. The Esterhazy Member is mined using conventional underground techniques at Mosaic's Esterhazy Potash Facility in southeastern Saskatchewan and by solution mining techniques at Belle Plaine.
Potash at the Esterhazy Facility area occurs conformably within Middle Devonian-age sedimentary rocks and is found in total thicknesses ranging from approximately 100 to 131 feet (30 to 40 m) at a depth of approximately 5,345 to 5,740 feet (1,630 to 1,750 m).
The typical sylvinite intervals within the Prairie Evaporite Formation consist of a mass of interlocked sylvite crystals that range from pink to translucent and may be rimmed by greenish-grey clay or bright red iron insoluble material, with minor halite randomly disseminated throughout the mineralized zones. Local large one inch (2.5 cm) cubic translucent to cloudy halite crystals may be present within the sylvite groundmass, and overall, the sylvinite ranges from a dusky brownish red color (lower grade, 23% to 27% K O with an increase in the amount of insoluble material) to a bright, almost translucent pinkish orange color (high grade, 30%+ K O). Carnallite is also present locally in the Prairie Evaporite Formation as a mineral fraction of the depositional sequence. The intervening barren salt beds consist of brownish red, vitreous to translucent halite with minor sylvite and carnallite and increased insoluble materials content.