O-Chem Blues

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A friend is a tenured prof at a local university and teaches the 9 AM organic section. My friend lamented the consumer behavior of students in O-Chem and mentioned getting slaughtered on some internet ratings site. Tenure is not an issue for this prof, but student evaluations are still a big deal.

The question my friend has trouble with is this jewel- “Is this going to be on the test”? This arouses considerable frustration and ill humor. Some profs have no taste for this cat & mouse stuff and will be upfront with what is on the exam. Others are more elusive and Darwinistic. One wonders if these lone standard bearers could have excelled on their own exams when they were in school.

We discussed the possibility of suitable replies that are courteous but firm. There is no need or benefit to a smackdown for insolence. Basically, students need to recognize the main themes of the chapters and answer reasonable questions therefrom. The key is to do the problems. That has always been the key to orgo.

Some have been scornful about “teaching from the book” and supplement their curriculum with content that suits their fancy. I think this is fine for certain upper level coursework. Where this strategy fails is when students need to comprehend the pillars of chemistry for later and more advanced concepts. Then other content becomes a kind of distracting indulgence. Chemistry is vertical.

The problem is that the academic expectations may ratchet up a few notches in college. Students who may be accustomed to getting good grades without too much sweat are often mortally threatened by the prospects of getting less than an A. But this is just a part of the total growth experience and a good prof will be sensitive to this frailty. The trick is to help these students find their own path and go for it.

Metals Odyssey

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My efforts in finding a particular actinide mine today failed miserably. Apparently, gentrification and McMansion horse operations have restricted the only access road for rabble like myself. Looks like I’ll have to get actual permission to visit the site. I’ll be more forthcoming with the identity of the mine when I can get a first hand account and pictures.

I did find some interesting pegmatite veins elsewhere. Pegmatite intrusions (or zones) may be enriched in interesting metals like rare earths. My samples could just be feldspar, but the xtal habit seems different.

This is the problem with being an “independent scholar” in this field. If I want an ICPMS or GDMS to get a sub-ppm level elemental assay, I have to fork over ca $400 a pop to get some numbers. An XRD is only good down to ~1 % phase purity. I could find a real geologist to pester, but that wears out fast. Gotta find a way to get some analysis done economically.

I spent some time panning for placer gold in a creek downstream of Ward. It was a complete bust. I drove away with a backache and wet feet. There are no lode mines visible in that area, so perhaps the absence of gold was determined by others long ago.

Aspen Starting to Turn COlor September 2009

Aspen Starting to Turn Color September 2009

The Joy of Bentonite

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As I write this post I hear and feel the wump, wump, wump of the contractors sledge hammer coming down on our concrete front porch. We could put it off no longer. Subsiding soil in the front of the house has dropped the soil from below the concrete stoop to the point where it was hanging on to the foundation by friction rather than by concretion. The stoop was beginning to succumb to the pull of gravity and it had to be torn out.

The eastern plains of Colorado right up to the foothills are covered by expansive soil. Bentonite and other clays swell, contract, and generally heave with moisture cycling. When you combine this with ignorant and shabby construction practices, you set into motion future remediation.

Measure it with a micrometer, mark it with chalk, cut it with a torch, beat to fit, paint to match, inspect it with a microscope.

There are scattered reports of amelioration of this expansive property by amending the soil with several % of lime.  Excessive additon of lime has the effect of enhancing the swelling, so care must be taken. I am unaware of anyone practicing this kind of art. Addition of lime (CaO and/or the hydrate)will make the soil alkaline, so some planning will have to go into the decision to amend soil for expansive properties.

Thoughts on rehearsal

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We finished rehearsal for the play last night. Full dress rehearsal with lights, sound, props, etc. Tonight we have paying guests.  This is my second production this year. I have to say that I have not been yelled at this much since third grade (or grad school). But rather than being thin skinned about it, I have taken it fairly well. It has been a positive personal growth experience, which is the point of it all.

The best advice yet has been “be a better listener” on stage. If you are present in the moment on stage, you can better cope with the inevitable slip ups and mangled or omitted lines.  Rather than spending your time thinking about your next line, try to be part of the flow. If somebody drops a cue line, you’re better able to improvise a line to steer the dialog back on track.

This is good advice in general. Like many people, in conversation I find myself thinking about what I’m going to say next rather than really listening to the person I’m conversing with. This is a bad habit and reduces conversation to a comingled set of monologs or pronouncements of opinion.

The other bad habit that seems to get worse with age and education is the tendency to answer the question you wished someone had asked rather than the one actually asked. This is an irksome and possibly incurable condition of mine that those around me suffer from. Participating in staged dialog has had the effect of causing me to be more aware of this.

Thursdays Link-O-Rama

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Need/want cheap terabytes?  Backblaze details how they put together 67-terabyte mass storage units for $7,867 each, or $117,000 per petabyte. This is what I like to see: do it yourself, shade tree engineering. Damned skippy!

The trouble with economics.  Caveats aplenty.

Religion. The divine misogyny.

Fareed Zakaria suggests greed is good, sort of.

What do the Russians really want?

California is on fire (again)

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The western wildfires currently in progress are having a huge effect on the clarity of the atmosphere here in the greater Denver area. The California wildfire in particular is discharging vast quantities of smoke into the atmosphere. Here, one thousand miles downwind, we are enjoying hazy days and spectacular sunrises and sunsets owing to the smoke in the air. Last night as the moon reached the meridian, it resembled a moon in partial eclipse in terms of the reddish aspect of its appearance. The long carbon footprint of California is casting a shadow upon us.

The Tejas Republic

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Well, shoot. Some Texicans are spoutin’ off about secession again. I’m kinda s’prised it took this long fer their sentiments to get voiced out in the open. Havin’ lived there fer a few years, I could see it comin’ a while back.

So let’s see. Before they split, we’ll set up a US Hong Kong-type city state in Houston so’s we git the port a’ Houston with its petrochemical complex and NASA. Then we’ll make sure we keep the military bases in San Antonio, sorta like Gitmo, and move the Pantex nuclear weapons reservation from the panhandle to the north. After that, we’ll slap a duty on their exports, divert the Rio Grande into Arizona for irrigation, make Galveston Island a US naval station, and claim the oil reserves in the gulf. They can have their West Texas crude.

It’s like a whole nother Central American country!

Day Trip to the Central City Mining District

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The Central City mining district had its origin with the Pikes Peak gold rush. Placer gold deposits found in Denver area streams were quickly played out. Miners followed streams like Clear Creek up the canyon to their source, staking claims on the placer deposits in the streams along the way.  Eventually, the placer deposits played out causing miners to search for the lode deposits along the hillsides. Underground hardrock mining was the inevitable outcome of placer depletion.

The Pikes Peak gold rush began in 1859 and is named after the high  mountain peak that is visible from 100 miles into the eastern plains. While the immediate area of Pikes Peak produced little or no gold, it was a useful point of reference for arriving miners and settlers.

In many ways, the various gold rushes in American history are simply examples of economic bubbles 19th century style. The discovery of a resource that can generate substantial streams of cash will attract large numbers of wealth seekers. Not surprisingly, chance favored the early arrivals in the bubble. Many a weary participant gave up, hoping only to break even. Others realize that there is more stability in providing supplies and services to the miners.

Abandoned Mill Near Central City, CO (Copyright 2009, all rights reserved)

Abandoned Mill Workings Along Russell Gulch Road (Copyright 2009, all rights reserved)

While mineshafts, adits, and tailings piles still mark the landscape in most mining districts, what has been lost for the most part are the mills. The photo above shows the remains of a mill operation between Central City and Russell Gulch. Mills were a crucial link in the generation of wealth from mining activity.

Mill Along Russell Gulch Road

Mill Along Russell Gulch Road

Mills were constructed near the richer lodes and were configured in various ways. Some processing buildings were built along the hillside and early mills had chutes with which to convey material  within the facility. Later mills had conveyors to transport materials.

Remnant of Surface Workings, Central City, CO (Copyright 2009, all rights reserved)

Remnant of Surface Workings, Central City, CO (Copyright 2009, all rights reserved)

Cominution was a key operation of the mill. Large rocks had to be reduced in size to expose greater surface area for value extraction. Stamp mills were very common and consisted of a powered camshaft that lifted and dropped a train of heavy cylindrical hammers on the ore. The output of the stamp mill was treated in various ways depending on the nature of the gold bearing ore.

Gold ore near the surface might be of a more highly oxidized nature from exposure to oxygen entrained in meteoric water. In that case, sulfur would have already leached from the formation leaving a higher level of metallic gold. Such ore was more amenable to extraction by amalgamation. Stamp mills could be constructed with mercury covered copper plates on the output side of the stamps. The mercury would amalgamate the gold particles from the mill feed, selectively trapping them on the plate. The amalgam would then be scraped off the plates and the mercury removed by the application of heat to evaporate the mercury. 

Gold ore from deeper deposits resisted direct amalgamation, however, and roasting was used to free the sulfur (and tellurium) from the value. Highly sulfurized ores would be roasted to liberate the gold from the sulfur in the matrix. The resulting calcined ore might be milled or just subject to mechanical agitation to dislodge the gold particles in a sluice or by amalgamation (source- discussions with mining museum people. I would like to find better documentation, however).

The extent to which amalgamation was used in gold recovery is largely forgotten or left unmentioned. The USGS has excellent documentation on this topic.  Chlorination by the application of Cl2 and cyanide extraction were introduced by the end of the 19th century as well, but that will be the topic of another post.

The folded rock in the photo below is shown only because it is visually interesting. Note how the various layers show signs of differential erosion. Nothing astonishing, just a reminder that seemingly ordinary things can be very interesting if one stops to have a look.

I’m going to get hit by a car one of these days from stopping at roadcuts. I can only hope it is over fast.

Folded Rock Formation , Roadcut on CO 119 near Blackhawk

Folded Rock Formation, Roadcut on CO 119 near Blackhawk

Question to Democrats: WTF??

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I really do not understand the manner in which the Democrats are responding to the outrageous lies and fascist propaganda that the Republicans are dealing out. Democrats- WTF??

Democrats should deal with Republicans in the same manner that they were treated in the days of DeLay and Armie.  The Republicans of congress are egg sucking dogs who only understand one thing- the sharp crack of a 2×4 between the eyes. The ruthless application of blunt power. Rough ’em up while they’re down – metaphorically at least. Because the inglourious basterds will certainly not offer bipartisanship when they are the majority again.

American politics is disgusting sometimes.  Especially now.