Esterhazy K3 Expansion Project

Increasing capacity at the world’s largest potash mining complex

Mosaic Potash | Canada | 2008-2024

21 Mtpy increased hoisting capacity

7.1 Mtpy increased plant capacity

380 ft. design height of headframe

Schreyer Award winner and Award of Excellence from the Canadian Consulting Engineers


  • Mosaic’s K1, K2, and K3 mines, which feed the Esterhazy K1 and K2 mills, currently comprise the world’s largest potash mining complex. The new underground mine at K3 will replace the older K1 and K2 mines once at full capacity, anticipated in 2024.
  • The scope included detailed design and construction management for two production shafts, headframes, and hoisting systems.
  • This state-of-the-art project involved sinking twin shafts to a depth of 3,350 feet, and slip-forming a headframe with a design height of 380 feet.
  • Various geological formations and water pressures at depth in Saskatchewan make shaft sinking challenging, and are compounded by the ever-present, highly concentrated brine that has the potential to affect both workers and equipment.
  • Lowering a large quantity of heavy mobile equipment and bulk material handling systems required innovative means to reduce shaft hoisting times as well as assembly times underground.


  • Hatch has been involved on the K3 mine from its initiation in 2008, starting with scoping-level studies and progressing through project development and construction. We will continue to partner with Mosaic until the K3 mine is fully commissioned and operational, expected in 2024.
  • Construction of the site included foundations, an electrical substation, ground freezing, shaft sinking, and two massive hoists.
  • Unique sinking techniques for two 20-foot diameter shafts, which had to be sunk through water-bearing formations, included ground freezing from surface down to a depth of approximately 1,600 feet to hold back the water while the permanent liner was installed.
  • Temporary support of the shaft ground wall was installed during shaft sinking to control the hazard of rock falls until the liner was installed while sinking progressed.
  • Construction activities were facilitated by means of working from a five-level shaft-sinking galloway.
  • A steel liner was used in the shaft for the management and control of the ground water.
  • To reduce underground construction time, modularization of shaft loading pocket steelwork was used underground.
  • The production shaft headframe will be constructed using modularized steel floors that will be jacked into position minimizing the construction durations and improving safety with more work being undertaken on the ground.


  • Upon completion, the K3 mine will be a world-class operation that sets a strong foundation for Mosaic's future potash production, while reaffirming their commitment to the growth and long-term sustainability of their business in Saskatchewan (Canada).
  • At over 380 ft., the North K3 headframe is the tallest structure in the province. It houses and operates the massive hoists and skips that will transport potash to the surface from more than half a mile underground.
  • The site also contains some of the largest Koepe hoists in the world (60-ton payload skips) to achieve the planned future production requirements. Designed by Hatch with a globally-responsive team of experts from Canada, Australia, and South Africa, the hoists will utilize leading-edge technology and state-of-the-art automation.
  • In February 2017, years of careful planning were realized when the team celebrated an important milestone—reaching potash at a depth of 3,350 feet.
  • First ore in the service shaft was achieved in December 2018, and commissioning of both hoists was completed shortly afterwards.
Fertilizer PDF Image


Fertilizer International magazine 

A case study of the Mosaic Esterhazy K3 Expansion Project was featured in the May/June 2021 issue of Fertilizer International magazine and is attached here with their permission. The full issue of the magazine is available through subscription on their website.

“Managing a project of this complexity and magnitude is no easy task. There were many keys to success and the K3 team demonstrated them all: exceptional preparation, strong teamwork, and personal dedication. There is no doubt that the best people in the industry are leading this project."

Joc O’Rourke | President and CEO, Mosaic Potash

Project numbers

Depth of shaft: 3,350 feet
Height of headframe: 374 feet
North headframe and shaft: 3,944 feet
Distance between shafts: 450 feet
Target mine production: 21 Mtpy
Investment: Approximately US$2 billion
Increased plant capacity: 5.3 to 7.1 Mtpy
People hours: 5.2 million
Reached potash at depth of 3,350

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