As AEM was developing the mine, it continued with the drilling program. The Suurikuusikko deposit, informally known as the Suuri orebody, has grown significantly since AEM’s initial investment. In 2004, it stood at less than 2 million oz of gold resources and it currently has more than 3 million oz of reserves and almost 3 million oz of resource.

AEM anticipates producing 75,000 oz from Kittila this year. “We have been mining for several months now and the mine has a significant stockpile of more than 200,000 mt of ore,” Boyd said.

Annual gold production is expected to average 150,000 oz over a 13-year mine life. “With the current reserve and resource of 6 million oz against the current production rate, the mine life would exceed 40 years,” Boyd said. “That’s not optimal. That’s why we are looking at shaft access to accelerate the extraction of the deposit.”

Kittila is currently mining the Suuri orebody via a 150-m-deep open pit. Ore is mined in 5-m benches together with waste rock using buffer blasting techniques and is loaded selectively to minimize dilution and maximize ore recovery. Hydraulic excavators load ore into 90-mt trucks.

For the next four to five years, Kittila will continue to operate as a surface mine before underground production begins in earnest in 2010. A ramp is under construction and its length currently stands at more than 4 km. The ramp is not only important for accessing underground ore, but also to establish platforms for drilling the deposit. “We have traced the deposit down to a depth 1,100 m—the limit of surface drilling,” Boyd said. “We will be in position later this year to start drilling from the ramp. That information is very important to us, because we are looking at additional infrastructure such as a shaft, which will allow us to access the deeper parts of the deposit.”

The underground mining method will be open stoping with delayed backfill. Stopes will be 25- to 40-m high and yield approximately 10,000 mt of ore per stope. To ensure sufficient ore production is available to supply the mill, approximately 4 km of tunnels will be developed each year. After extraction, stopes will be filled with cemented backfill to enable the safe extraction of ore in adjacent stopes. Ore will be trucked to the surface crusher using underground haul trucks via the ramp access system.

The ore will be processed at a 3,000- mt/d concentrator, using flotation, pressure oxidation and carbon-in-leach circuits. Gold is recovered from solution by electrowinning and then poured into doré bars using an electric induction furnace. “We extended the commissioning phase due to fine tuning in the autoclave circuit,” Boyd said. “The recovery at the mill since the last official update [May 2009] has improved from about 30% at the end of April to more than 60% today.”

A lot of that recovery improvement, Boyd explained, came from modifying the retention times of the concentrate in the autoclave circuit. “We continue to work on optimizing retention times and finding the right acid conditions within the autoclave,” Boyd said. “We are fine tuning the flotation circuit ahead of the autoclave to float off the carbon. We are doing a lot of these things now in a step-by-step fashion to bring the recoveries back up to that of the test work, which has above 80%.”

The operating environment in Finland has been good for AEM. “The local population is extremely supportive as has been the local government,” Boyd said. “There is a mining culture and an understanding of mining in the region. There is a defined permitting process, so a mining company knows exactly where it stands throughout the process.”

Historically, gold deposits in Scandinavia tend to be small. “What surprised us about the Suuri deposit was the sheer size,” Boyd said. “This one is a bit of anomaly because of its size. What’s encouraging is that we have outlined a reserve and resource of 6 million ounces and we have only drilled the structure to 1,100 meters. It’s open at depth and internally because we have picked up additional lenses at depth. We do see those lenses in the upper part of the mine. We have a property position that covers about 20 kilometers of the favorable geology and we still have a lot of work to do along that strike extent.” AEM believes that is significant potential to grow what is already a large deposit.