By Lise Anne Lepage
School: E.S. Laird Middle School, Lloydminster, SK
The day began with the teachers and geologists waking up bright and early for breakfast in Moosomin. We gathered by 7:30 and were on our way to Rocanville Potash Mine, which was approximately a half hour from Moosomin. We had toured the Potash Interpretative Centre in Esterhazy the night before to get a better appreciation for what we would see today. If you can't get underground at a mine, and most people can't, this is a great way to see what underground is like - what a great resource.
School: E.S. Laird Middle School, Lloydminster, SK
The day began with the teachers and geologists waking up bright and early for breakfast in Moosomin. We gathered by 7:30 and were on our way to Rocanville Potash Mine, which was approximately a half hour from Moosomin. We had toured the Potash Interpretative Centre in Esterhazy the night before to get a better appreciation for what we would see today. If you can't get underground at a mine, and most people can't, this is a great way to see what underground is like - what a great resource.
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| Potash Pete in Esterhazy |
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| Looking at Mine Plans, Potash Interpretative Centre |
Once we arrived at the mine, we were greeted and escorted to a training room where we watched a 15 minute video which gave us a bit of history about the mine, as well as an overview of what we would be seeing underground. From there, we geared up and were on our way to Shaft #2, which is basically an oversized elevator. This one transports only people and machinery up and down the mine. The elevator moves at approximately 1200 ft/min, so we reached the mining level (3200 ft.) in about two and a half minutes. From there we were on our way to the four rotar mining machine. All of the mining machines at Rocanville mine had historically been named after bears and have individual names such as Kodiak, Koala, Panda, and Polar. They ran out of bear names and are now naming new mining machines after cats. The mining machine that we visited was named Grizzly and was located approximately 8 miles from the main shaft.
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| In the cage heading 3200 ft. underground |
As you approach the Grizzly miner machine, you begin to drive beside a system of conveyor belts, which transport ore from the Grizzly to the skip. The belts have a consistent clink, clink, clink, as parts of the belt pass over the rollers. The closer you get to the Grizzly, the dustier it becomes, almost thick with a haze of potash dust. When you approach the miner you recognize that it is the size of this thing really is huge. It’s cutting surface cuts into the face of the rock at 8’6’’, carving a path through the potash ore. It is 26’ wide, with 4 cutting blades that interlock as they create minimum 8’ diameter carvings into the face of the rock. The amazing thing is though, that this giant machine can be operated fully automatically when the operator of the machine has set the Grizzly on the correct path, sensors in the middle of the carving surface can tell exactly what percentage quality of ore is being harvested. The ore that is carved and broken off of the face is transported via an enormous auger extending as an arm from the Grizzly and deposited onto the miles of conveyer belt stretching beside it. Amidst the dust the Grizzly operator stays clean, as he has a large ventilation tube that travels directly beside him and blows fresh air at the operator’s face.
When the Grizzly shut down and backed away from the cutting face, it became eerily quiet underground. The only sound (apart from the voices of my fellow tourists) was a slight crackling. It reminded me of a thin layer of ice slowly cracking as people walked across it. When asked, my tour guide (a mine engineer) stated that this was a result of the pressure being exerted from the ground above. After the Grizzly makes it’s three passes (totaling ~ 73 feet wide) the ground has to settle to redistribute the pressure, which causes the opening created to shrink about 2 inches, but is completely normal.
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| Collecting potash samples at the mine face. |
From the Grizzly we toured over to the Skip. The Skip is a large dual bucket elevator system that is also fully automatic. The Skip is exclusively used for transporting ore from the conveyor belts into one of the buckets on the Skip. Once it is full with it’s 32 tonnes of ore, a bell rings and it is sent up to surface. At the same time, the other bucket travels down to the bottom to be filled. It takes about 90 seconds for the skips to travel from the ore level to the surface to be emptied. This process is continuous, happening 24 hours a day, (unless the mill is full) always filling up with new ore.
After we went to the Skip, we started our way back through the network of tunnels to the shaft. On the way back, all 3 of the jeeps stopped and we all turned out all of our lights, shut off vehicles, and experienced the blackness and quiet of the mine. I put my hand in front of my face and tried to see it, but there was no way I was going to be able to see my own body part. I brushed my nose with my open palm, and still could not see the fingers one inch from my own eyes. It was totally amazing to experience the darkness, and what could be, if it were not for the giant electrical cords running along the backs of the tunnels, and powering the lights, Grizzly, and essentially giving the mine life.
After going underground, we then took a tour of the mill and control room, where the operators extract the potash from the ore. We first went to the control room that is seperated into an underground and surface processing side. On the underground side, an operator sits in front of a plethora of computer screens, in order to keep an accurate tab on the weight, quality, and quantity of ore that is being loaded onto each conveyor belt. This is monitored through video cameras attached to each miner, as well as sensors on the conveyor belts, and the sensors in the mining machines. The control room also has an above ground side, which uses the same style of sensors to monitor each containment unit, and the quality of the product. We then went to the cells where the potash ore is combined with brine and an animal fat and then frothed with oxygen to allow the potash to separate and float out of the solution. Small paddles scoop the froth into a conveyor, and transport it to a different cell. The potash ore still stays granular during this process. It’s amazing to see the crystals come directly out of the mixture, and that they are still bigger than the crystals in coarse salt, despite their having mixed in a liquid suspension.
In the next cell the granular potash is floated and rinsed again, to ensure quality of product. The river of potash then flows into a steel drum centrifuge, spinning the water off of the potash crystals like your clothes in a rinse cycle of a washing machine.
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| In the control room - computer screens showing mill process |
From there, we were shown the compacting machines where the material that is too fine to be used gets compacted and pressed together into larger sheets. These larger sheets then get broken down again into the smaller ideal pieces that are required for the potash buyers. These machines were very hot, as it took a lot of energy to complete the process and keep the potash very dry. The potash recovered from this process was still the same grade, but was not as shiny as the potash that did not have to be compacted.
The potash is then loaded onto either rail cars (most common) or semi trucks. At Rocanville mine they can load 100 rail cars in 24 hours. Each car can be loaded in about 10 minutes, and it can hold 120 tons of material! It was amazing to think about the amount of material coming out of the ground and utilized in so many different applications.
We were then able to go back and visit with some of our tour guides while we ate lunch and learn more about how they enjoy the mining industry, and the variety of activities that they participate or volunteer for in the communities surrounding the mine. These people are not only an asset to the mine itself, but their skills are also valuable to their communities as they offer their time and service to the different activities in the area.
A great big Thank you goes out to Rocanville mine and it’s employees. Their hospitality allowed for this amazing learning experience. I loved every minute of it.
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| 5 cranes at work on Rocanville expansion |
