The Difference Between Rock and Rock

What’s the difference between the waste rock on the Ute Ulay site, and crumbling rocks on nearby parts of the Rocky Mountains?

Above is waste-rock at the Ute Ulay. Waste rock is a by-product of lode mining. The miners follow a vein through the inside of the mountain, searching for a rich ore that can then be processed and sold. After the rock has been drilled, and blasted with dynamite, the resulting material is mucked out (shovelled up and taken away). Next, the ore is sorted; the workers look for particular colours and types of rock that they know are mineral-rich. Those are set aside to be crushed, etc. and sold. The rest is waste rock.

Above are some naturally crumbly bits of the Rocky Mountains. The Rockies are geologically young, which means they are steep, and lots of bits of crumbly rock are still falling off them. It struck me that these crumbly rocks had come from the same mountains as the waste rock, were about the same size as the waste rock, and are heading into the rivers in the same manner that the waste rock does.

So what is the difference? The reason it matters, is that according to current practice here, waste rock requires remediation, whereas naturally crumbly mountain does not. If waste rock is part of the same mountain, and is the same shape and size as other crumbly bits of mountain rock, why are we not either:

a/ just ignoring it.

b/ remediating the entire mountain?

The reasons are twofold. Firstly, the waste rock has been taken from specifically mineral rich areas, and therefore has a higher mineral (potential pollutant) content. Secondly, the crumbly mountain rock has been subject to weathering forces which gradually erode it. So the waste rock is leaching out more minerals, at a faster rate than the naturally crumbling rock. That creates the potential for risks to human health, amongst other things.

There is lots of waste rock up at the Ute Ulay. Part of the process of developing the Ute Ulay site will be to keep people’s contact with the metals present there (lead mostly) to a minimum. After a meeting this morning with representatives from CDPHEDRMS, and Colorado Brownfields Foundation, I have a few things to ruminate on regarding the future shape of the Ute Ulay.The remediation strategies proposed for the Ute Ulay would drastically alter some of the historically important landform.

There is no doubt that the landscape will change significantly. But this is just another stage in the history of this place. It is also an opportunity.

As a landscape architect I am regularly (partly) responsible for changing places. I remember the first site visit I ever went on. It was to a run-down victorian seaside resort called Rhyl in north Wales, and I felt the weight of people’s memories weighing down on me. Who was I to propose any changes?! But it’s part of the job to develop the confidence to alter places – you just hope that you can make it better for most people.

A year after the park in Rhyl was completed, I went back to check on the planting and overheard people telling each other how much they liked the place. It meant more than any award ever could.

Going Underground

A couple of days ago I went underground. Literally.

It all started with a drive to Ouray, which is 19.4 miles away from Lake City as the crow flies. But because (at least in the winter) you have to drive around lots of mountains, Ouray was actually 136.5 miles away.

Once there we got to a road which reminded me of the Alpine Loop. The sign on the locked gate was a little ominous.

But our business was further up that road – so we continued on. Past evidence that the sign was accurate…

…until we reached a mine that is being readied for working again after a long period of inactivity. The price of precious metals is currently very high (March 2012). In times of uncertain economies, gold and silver tend to do very well on the markets. I suppose they seem somehow timeless, secure investments. So, it is currently worth re-investing in mines which had previously been un-economic to run.

The history of mining is a constant iteration of boom and bust cycles. I imagine all this activity means that we’re currently in a boom. It was possible to see old mining buildings, still on the site from one of the previous mining booms.

Once up there, we donned the requisite safety equipment and headed down (actually up – though it felt like down) into the mine. It was a little bit muddy, but not unpleasant. The hissing of water and air pipes accompanied us. Many mines rely on air being pumped into them, but this one has natural ventilation, which will be helped along by fans in certain places, as the mine develops.

The miners who were giving me the tour (I will call them Luckies No. 2 & 3) showed me where some fellow miners were drilling into the wall of the mine to make a drill station. From the drill station they will sample the rock to find out the location and size of the vein that they will be mining.

To extract metals, the miners drill into the rock face, and then load it with dynamite to blast out the rock so that they can take the ore to be milled. There is an art to everything; the number of holes you drill, the direction they point in, and the timing of your explosives can all make an important difference.

I was at the mouth of the mine when this particular round went off (far away, and around a corner mum, don’t worry). I felt my lungs compress as the series of explosions took place. The corrugated tin building shook, and I screamed, ducked, and tried to cover my head and my ears at the same time. I am very tough. Luckies No. 2 & 3 thought so.

What all of this mining is about, is extracting metals for stockbrokers to trade, for us to wear, and to use in medical, digital, and transport applications (amongst many, many others). We all use this stuff. It’s in the computer you’re using now. And the amazing part is that it was created through the interaction of water and heat and rock – a process called mineralisation. These minerals form in a crack or void that was already present in the rock, and that shows up as a vein.

Some are very skinny, others are wider, and some are fractured. This one is a real corker, each colour represents a different substance, some of which we value very highly. The white is quartz, the yellows are various stages in oxidisation of minerals.

When wandering around the Ute Ulay I often see pretty coloured rocks on the ground and I want to pick them up. I wonder if the very first miners were inspired by pretty rocks too.

Mother Lode

A mining claim is the right to explore for and extract minerals from a portion of land. Under the General Mining Act of 1872 (still in place today), ‘all citizens of the United States of America 18 years or older have the right… to locate a lode (hard rock) or placer (gravel) mining claim on federal lands open to mineral entry. These claims may be located once a discovery of a locatable mineral is made. Locatable minerals include but are not limited to platinum, gold, silver, copper, lead, zinc, uranium and tungsten’. 1

So in theory, any American can prospect and mine on any of the public land in Hinsdale County, excepting wilderness areas which are exempt from this law. In reality, setting up a mine is an expensive, and risky business. The histories of almost all the mines in the vicinity of Lake City are tales of boom and bust, and this is a pattern that repeats itself across the world.

Before 1872, although legal under state and territorial law, mining in the west was illegal under federal legislation. In 1865, it was proposed that an army be sent to the West (Arizona, Colorado and California) to expel all the miners and to protect the Government’s mineral rights, and that the government itself should work the mines.

However, representatives of the West counter-argued that miners were doing useful work by settling new lands and helping commerce. And so a series of laws were passed that protected the miners’ claims.

Today many people have mining claims. The plans of these claims show rectangular strips overlaid onto dense contours, but the interaction of plan and 3D geometries has some interesting consequences.

The surface area of the claim is much greater than it appears from a plan (top-down) perspective, since the rectangular claim is draped over some very steep terrain. See this animation from Spike Productions of mining claims along the alpine loop (including the Ute Ulay).

At first sight the mountains and claims make for a very odd combination. However, when you consider that the actual mineral extraction is happening underground, it ceases to matter what the surface topography is. As a miner you can continue drilling and blasting and hoping in your rectangular cuboid space (with an irregular lid) under the mountains.