Yah I looked it up but couldn't find too many details other than its there. Unfortunately it seems to be on private land so would be a bit tough to get to to take a look.
Coal is laid-down by past vegetation - layer upon layer over thousands of years , then compressed. Nothing extra-terrestrial in Chelmsford. The only thing that was ever extra-terrestrial in Chelmsford, was when I cycled from London up to Harwich, to catch the ferry to Holland, this back in June 1988...
...makes one wonder at the amount of earth being moved to extract all these ores. Gotta move and process tons and tons of earth to extract the tiny amount of "good" stuff. All that production cost, plus a healthy profit for the companies that do it, ALL of it comes from those little bits and flecks of "good" stuff we see in those samples. Imagine the ratio of element vs "waste".
A copper deposit, if near the surface can be profitable with as little as 1.5% to 3% per ton of ore. If of course you can extract to ore body from the surface with open pit methods. A rich Copper/Gold vein deposit needs to be at least 1-2 ounces of Gold per ton when worked in the more traditional tunnel & adit/stope method.
You might be able to find a few microdiamonds but economic diamonds come from kimberlite or lamproite intrusions that formed at extremely high pressures deep in the Earth. Uranium could form in the sediments that fill impact craters but these form more due to interfaces between oxygenated and reduces fluids and wouldn't really be related to an impact.
True, but that isn't the case here, the Grenville orogeny is quite well documented to the south and created what would have been one of the highest mountain ranges on Earth, though its been planed flat at this point.
