Cementation USA has completed sinking the deepest shaft in the United States at the Lucky Friday Mine in Mullan, Idaho. With a finished diameter of 5.5 meters, the Lucky Friday #4 Shaft was sunk to a final depth of 2 922 meters below surface. The project is moving into the furnishing construction phase where shaft steel and the final conveyances will be installed. Project completion is scheduled for late 2016.

“The sinking of the Lucky Friday #4 Shaft is truly a world-class achievement. Each of the many Hecla and Cementation employees, suppliers, and subcontractors that worked toward this moment should be very proud of what has been accomplished. Special thanks go to our client, Hecla Limited, for the tremendous safety and project support we’ve received. This support was integral to the incredible safety and shaft sinking records that have been achieved,” said Justin Oleson, President of Cementation USA.

The Underground Mining platform, which is currently sinking 15 shafts worldwide, has sunk the deepest single lift shaft in the world at South Deep Mine in South Africa, the deepest shaft in Canada at Kidd Mine D No.4 Shaft, the deepest single lift shaft in the United States at the Resolution Copper Project, and now the deepest shaft in the United States.

“Reaching the bottom of #4 Shaft is an accomplishment that the Hecla and Cementation project team should be very proud of,” said Eric Smith, General Manager of Operations of Cementation USA. “The project team not only overcame many technical and logistical challenges, but also maintained an ethos of continuously identifying
ways to enhance safety and project performance.”

Completion of this shaft is a major milestone for the historic Lucky Friday Mine which has been in operation for over 74 years. The shaft provides access to lower mining levels which increases operational flexibility and extends the life of the mine by 23 years. This milestone occurs in the same year that Hecla Mining Company is celebrating its 125th Anniversary.

The Lucky Friday #4 Shaft is a vertical shaft that begins underground, which makes it a Winze in mining terminology. A Winze is an internal shaft which requires the equivalent of a shaft headframe and hoisting system to be installed underground before the excavation activities can occur.

Hecla selected Cementation USA to sink the shaft, excavate accesses, stations and pockets, and install the related infrastructure, which include a state-of-the-art fully automated 200 tonne per hour material handling system, a 1 892 liters per minute water pumping system, a centralised refrigeration system with 977 tonnes of cooling capacity and a batch plant.