Could you possibly tell me who reworked the dumps in the 70`s 🙂

The first person I know of to do any work in the area was a Mr Gregory a mining engineer, this was in the mid 1960's, he mainly tried precipitation using old horseshoes in launders to attract the mineral deposits, he then moved on to bringing in some plant to process dump material, Mr Gregory was on the site for a few years. Although people were very sceptical about Mr Gregory's attempt to make a living from his activities, it is said that he did in fact make a reasonable sum of money from the project.
Later work with the heavier and more extensive plant was put in place in the 1970's and stayed until the early 1980's, I am not sure who financed the operation, but I believe that Consolidated Gold was involved at one point and then I think Rio Tinto Zinc also had a hand in the operation.

Steve

According to Richardson, dump removal/ treatment started in 1965 and was carried out by a succession of companies. this had ended by 1979.
In 1989 a drilling program to a depth of 4000ft latter amended to 2000ft was planned to test for tin that may lie beneath the copper zone but this came to nothing

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Yes that's right, the 1965 start point was Mr Gregory's operation, when he finished it then moved through various other companies, some test drilling was done, I can remember looking at core samples that were taken, but I cannot say to what depth the drilling was done.

Steve

I remember in the 1960s finding hundreds of horseshoes on the site, used for precipitating copper from water running through the dumps

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Regarding Dump reworking at DGC:

Ernest Gregory (cross dressing mining engineer - interesting character) had been poking around DGC in the late 1940s before disapearing into the wilds of Africa. By the mid 1960s he was back at DGC and was operating both a copper precipitation works and a tin recovery plant. During this early phase Gegory had a shaking table in a wooden shed. In 1969 the mill was remodelled by Roger Harrison. The shed was replaced by a pair of Nissen huts containg four tables. A jig was erected at the top of the dump and material was transported in suspension from the jig to the mill. At this time some thought was given to extracting fluorspar, however this didn't happen due to high arsenic content. For some or all of this period the operation was known as Devon Great Consols Mines Ltd. By 1973 a new company, Redcaves Ltd was formed with a large influx of Canadian money. This led to a further upgrade of the mill. The Nissen huts were replaced with a new mill containing: a bill mill (still in situ), four shaking tables (latterly increased to eight and finally fifteen), a cyclone, a magnetic separator and spiral classifiers. The company changed again in March 1976 when the operation was taken over by Nottsvale Ltd and again in 1977 by Tamar Valley metals Ltd. Operations ceased in 1978 due to a massive fall in the tin price.

Regarding Dump reworking at DGC:

Ernest Gregory (cross dressing mining engineer - interesting character) had been poking around DGC in the late 1940s before disapearing into the wilds of Africa. By the mid 1960s he was back at DGC ..........

I remember Ernest Gregory very well, and as you say, quite a character, he was very well known in the area and was the topic of many a conversation at the loacal pub...he was always considered fairly ecentric! Rumour had it that he eventually underwent a sex change operation in London...but how much truth was behind it I do not know.

There also used to be a launder filled with crushed crab shells apparently being an attempt to precipitate germanium from the mine waters.

I do like the bit about the cross-dressing mining engineer.... I remember the DGC activities being the subject of persistent rumour and gossip when I was at CSM around that time.

On a slightly different tangent, I remember there being a small-scale streaming operation in the Brea area about that time. It was involved in some way with a letting agent in Camborne called Whear who were landlords to quite a number of CSM students ( who tended to live in and around Camborne at the time, having lectures at Fore St and Condurrow and of course no Hall of Residence at the time )

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There also used to be a launder filled with crushed crab shells apparently being an attempt to precipitate germanium from the mine waters.

I am intrigued- can you expand on this

Tamarmole

There is a few ppm of Ge in the mine waters at DGC and the concept was that the Ge would precipitate by ion interchange with the Ca and P in the chitin and calcite of the crab shells.

Theoretically it was off the wall but not impossible and Ge at the time was the wonder semi-metal for transistors and light sensitive materials. I seem to recall an old BBC programme at the time also visiting DGC and showing this as well as the intermetallic copper displacement - must have been late 1960's.

Was this why water was being piped from Blanchdown Adit to the mill in the 1970s?

Tamarmole

Was this why water was being piped from Blanchdown Adit to the mill in the 1970s?

Tamarmole

Sorry, no idea. I just remember the germanium story and will try to dig out some photos from the time if I can find them.

On the subject of germanium in his book on the early tin trade Hatcher mentions a research report by the Royal School of Mines (1954). The report stated that analysis has shown that Cornish tin ores contain traces of germanium and cobalt. He thought this a promising line of investigation as by the presence of these impurities it may prove possible to distinguish objects incorporating Cornish tin and therefore provide evidence, either positive or negative, of the trade of tin at that time.

I did a little bit of digging and read a few fairly recent papers on the subject but have never seen this line of invstigation mentioned. Do you know whether anything came of it?

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Tin and germanium occur in a number of lead sulphosalts and these have been recorded at a number of Cornish mines. However the principal ores of germanium are germanite and renierite (copper, iron, germanium sulphides). Both have been identified in DGC ore samples. The paragenetic association of these minerals is with the copper zones of the Cornish lodes although the complex tin germanium lead sulphosalts have been detected in the tin zone.

Thre cobalt generally occured as the arsenides smaltite and erythrite and as the sulpharsenide cobaltite with nickel, bismuth and uranium and lower temperature mineralization within the cross-courses at Dolcoath ("a few tonnes of cobalt ores" according to Dines), East Pool (4.5 tonnes), Dowgas (4 tonnes) and St Austell Consols (about 250 tonnes of mixed cobalt and nickel ores).

Thanks for that. :thumbsup:

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I mentioned the DGC/germanium topic to Charlie Daniel last night (Charlie was involved at DGC in the '70s), he reckons that the crab shell recovery system was a Gregory wind up staged for the TV news. The comment being that many of Ernies ideas were not backed up by respectable science.

Tamarmole