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What is Karst, What is Potash, What is Nash Draw?

KARST (click here to see a nice brochure explaining karst terrain from the University of Texas) is a landform with depressions that are caused by rock underneath the surface being dissolved away by water.  Usually when people think of karst terrain they think of places where there are caves and collapsed caves.  Where caves are collapsed there will be depressions, or even holes, into which water can drain and continue to dissolve water-soluble rock below.

Can you think of a more dissolvable rock then rock- salt?   About 250-million years ago the Permian Sea dried up and left a deep layer of salt behind that got covered over by other evaporite rocks (mostly limestone) and then sediments brought in by runoff from surrounding higher lands.

NASH DRAW:  Nash Draw a relatively small area in the larger Permian Basin where those caprock limestones and sediments just didn't do the job of protecting the deeper layers, allowing water to flow downward through them, and the land sank down from a hundred to several hundred feet as the salt beneath it dissolved.  [For a look at a place at the periphery of Nash Draw where there are 'sinkholes' that allow water to go very deep, very fast today, click here].

That happened here about 600,000 years ago, and as a result we have Nash Draw!

The Nash Draw depression with its ponds and lakes as seen from near the United Salt Corp facility on the northwest arm of the draw, the cliffs on the east side are the destination for Parts 3 and 4:

Nothing spectacular, just a Y shaped depression with a wide tail.  In the depression itself there is little salt left, but the Permian salt layer still exists undissolved in all directions away from the depression.  And as you climb out of the depression, salt is nearer to the surface than farther away from the depression where sediments are deeper, so people are mining salt on those edges.

The United Salt Corp mine and processing facility at the northwest end of the draw (next to the main Mosaic potash mine complex, it is hard to tell where the one ends and the other begins on the surface, underground they are mining at different levels):

What salt are they mining?  One salt is normal sodium chloride salt, as in table salt, or water-softener salt, or snow-melt salt.  Another set of salts contain mostly potassium rather than sodium.

POTASH (click here to see my source of information, another nice brochure, this one from New Mexico Tech) is the collective name given to several salts that are dominated by potassium.  Potash is used in agriculture as potassium fertilizer, and also in several chemical manufacturing processes.  It is quite valuable and, unlike sodium salt which is common, it is not common.  Sylvite, or potassium chloride, is added to table salt, sodium chloride, to make "light" salts.  It is the more common potash salt.  A less common potash salt is the mineral Langbeinite, which is composed of potassium and magnesium sulfate.  New Mexico is the only place where Langbeinite is mined in the world!

These mines are deep underground.  The potash layers tend to be relatively thin in the larger matrix of rock salt (sodium chloride).  Mines are very extensive, and when you see a tower where there is a shaft for bringing workers in and out or salt out, or air in and out, the underground works can extend miles away, with six miles the current maximum!  

So when you drive even miles away from the mine shaft hoist towers, you may still be driving above miners working below.  these miners take gargantuan amounts of these minerals to the surface with giant scrapers that carve up the walls and deepened the mine, and loaders that take the broken mineral to the shafts where it is brought to the surface for processing.

Abandoned shaft for one of the Mosaic potash mines.  Mosaic has the largest active mines in the area and quite a few that are no longer producing ore of sufficient quality, and so are abandoned:

Processing salt and potash to obtain the purity and mix desired takes water and excess water is usually allowed to run off around the tailing piles.  Tailings are materials brought to the surface to construct the mine, including the overlying sediments, some salt clay mixtures, and other poorer grade mineral zones that were mined through to get to the purer material.

As a consequence of the processing, there are lagoons below the mines where these solutions are allowed to evaporate, and depending on the time of year, temperature and rate of evaporation, the concentrations can vary and with those concentrations the life in these brines also varies, from deep blue greens when water is warm and somewhat dilute to wine red when the water is both warm and very concentrated, allowing only a red bacterium to prosper.  This is what is seen later in a typical year in the Great Salt Lake, Utah.  The South Arm is blue-green, the North Arm is wine red.  Quite striking.

Ponds and lakes in Nash Draw:

The water budget in Nash Draw has been calculated to be 40% from mine processing runoff and 60% from precipitation and discharge of springs.  It is springs that feed the salt lake called 'Salt Lake' by English speakers, and 'Laguna Grande de la Sal' by Spanish speakers.  Somehow the Spanish name sounds almost romantic, so we will stick with that one.

Laguna Grande de la Sal:

There is one active oil drilling enterprise in the bottom of the draw.  It is an experimental drilling project, sponsored by industry and government in partnership,  that is drilling down and then nearly horizontal to seek to learn how to obtain oil from a very tight formation. If the pipe collecting the oil has a lot of exposure to the formation holding the oil, it will be able to pull up a lot more then what could be obtained with a simple vertical hole.

The only oil drilling platform in the draw, to the right on the other side of the Laguna Grande de la Sal.  To the left of center is a United Salt Corp. plant that is making salt, as it is done by seas and oceans, and also at the edge of the Great Salt Lake in Utah, by evaporating salt water from this spring-fed salt lake:

What can't be seen well in the above photo because of the lack of height for the camera is that this plant is surrounded by diked-off areas of the lake, where water is evaporated to a certain extent to drop out the sulfate and magnesium and calcium salts, and then the fluid on top is pushed into the next pond where almost pure sodium chloride will drop out as the fluid evaporates to dryness.  

Attempt to see evaporation ponds around the United Salt Corp. plant in the south part of Nash Draw on the edges of Laguna Grande de la Sal, with an even better view of the oil drilling platform just discussed:

Turning right from this vantage point several large ponds, and the berms that separate them, can also be seen.  These may be remnants of another operation not now active, run by the former US Refining Corp.

Large ponds that may now be inactive at the very southern tip of the Laguna Grande de la Sal:

Just to the right, south of these ponds, is a rise beyond which lies the Pecos River and the town of Loving, New Mexico.

View to the town of Loving, New Mexico:

The formerly large enterprise called US Refining Corp. had quite a plant here at one time.  An excellent road was built from Carlsbad, New Mexico, directly to this plant.

Abandoned US Refining Corp. plant:

When I first saw these concrete structures, probably used for refining salt in very controlled batches, I thought I was seeing "gargoyles" staring down into the bottoms of the reaction/evaporation concrete canyons.  

No doubt there were movable dividers in these structures to allow very specific precipitation of minerals in the evaporative cycle, and these "gargoyle" structures were holders of manipulators of various sorts to stir, skim and pull salts or solutions out as part of the process.

As you leave the draw from here to go to Carlsbad on the US Refining Corp road, you will pass many active oil fields.  

There is a good reason why there are no active oil fields closer in, except for that one experimental platform.  In 1973 there was an explosion in a potash mine that injured 10 workers.  The cause was an oil well nearby that was producing gas as well as oil (they often go together) and the gas was under pressure and entered the mine and was ignited.  Quickly the requirements were changed and now there has to be a quarter mile standoff of an oil well from the nearest underground mine works, and a half a mile for a gas producing well.  

Since the potash and salt mines are very extensive underground, it just makes sense not to put an oil or gas well anywhere near where they are mining, or where they might mine in the future.

Oil pump and storage tanks on the higher part of the margin of Nash Draw, with Laguna Grande de la Sal in the background:

We entered Nash Draw from the northwest side, and are now leaving it on the southwest side.  On the next page we will come back and explore the middle of Nash Draw.  Then on the last two pages we will take a walk on the wild side?  No, just the east side.

Go to Part 2:  Central Nash Draw

Go to Part 3:  A Walk North on Livingston Ridge

Go to Part 4: A Walk South Along the Edge of Livingston Ridge

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