Tag Archives: boreal forest

What is an Open Pit Mine Anyway?

“I didn’t realize it was all above ground – I thought we’d be going underground, like in a  coal mine or something.”

That’s the reaction my sister had when I took her to visit one of the large operations north of town. So I thought I’d post about how roughly 20% of the Athabasca Oil Sands deposit is probably going to be developed.

When we mine oil sands, we’re not digging tunnels into the ground like you might find in a Disney cartoon about dwarves, or the Upper Big Branch mine in West Virginia, the one that recently and tragically claimed the lives of 29 miners. When we talk mines in the oil sands, we’re talking about open pit mines. Big holes. In the ground.

“Big Holes”

Open Pit Mine - courtesy of alexabboud

open pit mine - courtesy of alexabboud

Yes, the mines up here are big. In fact they’re quite large, large enough that you can see them from space.

But they’re also temporary. People seem to forget that.

Companies that work in the open pit mine business here in Fort McMurray region are required to reclaim all of the disturbed land. It doesn’t matter if that land had been dug up for the oil, just had a building on it, or had a road through it – if it was disturbed, they are required by law to return it to a productive, ecologically sound state.

Complex Issue

Dick and Jane - courtesy of The GC Four

courtesy of The GC Four

But before we get going, let me say that open pit mining and everything that it entails is complex. Extremely complex. I am certainly not an expert, and what you’re getting here is the “Dick and Jane” version. If you are looking for some highly technical, detailed information, let me point you to here and here.

As well, there’s all sorts of regulatory/environmental requirements that companies need to comply with before any work can proceed – it’s not like you can just go start digging away and sell the oil. If you’re interested in what the people of Alberta are asking the companies to comply with, check out the Energy Resources Conservation Board “Acts and Regulations” section or Alberta Environment’s “Oil Sands Environmental Management” section.

What Exactly Are the “Oil Sands”?

First off, we have to start with the particular matter that makes up the oil sands, and where we find it. A grain of “oil sand” is a tiny granule of sand, surrounded by a thin layer of water and minerals, which is then in turn surrounded by a thin layer of heavy oil called bitumen. In order to separate the sand, water and oil from each other, it needs to be heated up and put through a separation process.

The oil sands deposits are, for the most part, underground. The oil sands could be half a foot below ground level, or it could be several hundred feet down. A general rule of thumb is that north of Fort McMurray, the closer you are to the Athabasca river, the closer it is to the surface. In fact, the river has actually cut its way through the deposit, and in the summer months you can paddle around and see it naturally seeping into the river.

Oil sands that are closer to the surface are good candidates for open pit mining, whereas the deposits that are further down are candidates for SAGD or In-Situ processes. It is thought that roughly 80% of the oil sands deposits in Alberta will have to be developed using different techniques than open pit mining.

Open Pit Mining 101

Open pit mining basically involves digging down until you reach the oil sand deposit, mining the resource, then filling the hole back in – but it’s a little more complex than that. Chances are, as we’re getting ready to dig, there’s a few things between us and the sands: boreal forest, muskeg and overburden.

Boreal Forest - courtesy of Ben+Sam

boreal forest - courtesy of Ben+Sam

Boreal Forest – Fort McMurray is smack dab in the middle of Canada’s Boreal Forest, which account for around 3,100,00- square kilometres. In order for mining to begin, the trees need to be harvested by a forestry company – so they come in and take the trees away to be put them to good use.

Muskeg – The kind folks who contribute to Wikipedia tell us that muskegis more-or-less synonymous with bogland but muskeg is the standard term in non-Atlantic Canada and Alaska (while bog is more common elsewhere).” So the top layer is a bog-type layer, very spongy and very valuable for it holds a lot of what is needed in order to help reclaim a site.

My understanding is that the muskeg layer is either dried and stored for future reclamation use, or is moved directly to another area that is currently being reclaimed.

like a layer cake, really

like a layer cake really

Overburden – there can be several different layers of “overburden” which needs to be taken away before we get to the oil sands, but it does not go to waste. It’s either stored for later use in reclamation, or, depending upon the quality and type, it’s used in the creation of mine roads, walls and other engineering uses.

Truck and Shovels – Extremely large trucks (heavy haulers) and shovels are used in the removal of the overburden and the eventual mining of the oil sands. Chances are you’ve seen some of the footage on TV, or on YouTube, but you do not appreciate how big they are until your right down in the mine standing next to one.

Here’s a clip of some mining in action… you have to remember that each of those trucks is about as big as a two-storey house and when fully loaded can weigh over 600 tons!

Separation – The heavy haulers take the oil sands away from the shovels and mine face to dump it into a complex set of systems (crushing units, conveyer belts, pipes etc.) that will eventually separate the resource into its component parts – sand, oil, water (and minerals). While the major operators all have different techniques to do this, the process probably involves a combination of heat, water, chemicals and physical processes.

Sand, Oil and WaterNow that there are three basic products, each stream has to be handled seperately.

  • The sand is either sent out for storage, to be used later for reclamation etc., or used right away to fill other areas.
  • The oil is either upgraded and piped away to refineries, or is thinned out (bitumen is extremely viscous, so it needs to be thinned out) and sent to upgraders or refineries elsewhere.
  • The water at this point probably has fine particles, some sand and some oil  – so it’s not “clean” water by any stretch. It will be reused in the extraction process, or sent out to a settling or tailings pond where the layers are allowed to further separate. This process, using tailings ponds, is probably one of the more controversial processes, and in fact, a major announcement from Premier Stelmach was made last week (Earth Day) where the government will “get more aggressive” on eliminating tailings ponds.

Property of Syncrude Canada Ltd. Gateway Hill: This 104-hectare parcel of land is among Syncrude's most mature reclamation areas.

Reclamation – At the end of the day, when the bitumen has been collected from the leased land, the companies are required to start the reclamation process. All the buildings are removed, the roads are deconstructed, the pipes are dismantled. In fact, the companies are required to gain certification status from the Alberta Government; they “must prove the reclaimed land can sustain vegetation and wildlife similar to that before disturbance.” [source]

Why not find out more reclamation information from Canada’s largest oil sands producers?

Want to Know More?

Well, why not come to town and check it out for yourself? You can even book an oil sands tour through Fort McMurray Tourism – and the great thing about their tours is not only do you go out to see Suncor Energy’s mine site, but you also get access to the Oil Sands Discovery Centre which “presents the history, science and technology of Alberta’s Oil Sands – the world’s largest single deposit of oil.” Not bad for one ticket eh?

Can’t make it to town, but you’re interested in some online resources?  Let me Google that for you!