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was in 1979, while taking refuge from yet another blizzard in a rather inadequate shelter on top of a Welsh mountain, that the opportunity of digging in a somewhat more exotic location was first mentioned. At the time, I was an undergraduate studying archaeology at Lampeter in mid-Wales, and the new excavation opportunity was a tin mill at Colliford, somewhere in Cornwall. At this time, no British tin mill had ever been properly excavated, but I think it was the thought of six weeks in sunny Cornwall that persuaded me that it would be a good idea to be involved.

I will remember the first three days of that dig for the rest of my life. Dense fog, combined with torrential rain and powerful winds tragically known as the Fastnet Storm, coincided with our arrival. Once the winds had abated, the sun shone, and very rapidly it became apparent as we dissected the mill and the surrounding dressing floors that we were revealing a very complicated and informative story.

The mill, throughout its life, from at least 1507 until around 1600, had crushed tin from the nearby opencast quarry, but it had been abandoned and refurbished on several occasions, each time becoming more efficient. A wide range of artifacts provided an insight into the character of the tin processing operations, and domestic rubbish gave us a glimpse into the lives of the tinners who had worked here. The true complexity of the site only became apparent during the post-excavation process and preparation of the final report.

DIGGING DEEP View of the interior of the stamping mill at Colliford. The wheelpit is the water-filled, stone-lined channel on the right. The channel leading under the two near ranging rods carried material in suspension from the stamps situated adjacent to the wheelpit. PHOTO BY DAVID AUSTIN
Understanding the mill proved challenging and rewarding, and it was during this process that I was smitten and decided I wanted to find out much more about the industry in which this mill had played a part. The landscape around the mill was littered with the earthworks and other structures left by the tinners. The obvious next step was to record and hopefully understand what could only be described as a confused mass of humps and bumps.

So it was on the last day of January 1983 that I set off with a plane table to tackle the earthworks in the valley bottom next to the mill. I really had no idea whether it would be possible or even worthwhile, as nobody else had ever tried to tackle this type of survey. I certainly did not know when I plotted the first point on the table that the results would be so informative that for the next 20 years I would be spending large blocks of time surveying and interpreting tinwork earthworks all over Cornwall and Devon.

The survey work revealed that it was possible to demonstrate exactly how the tinners had used different methods to extract tin. By doing a detailed analysis of the streamwork plans in particular, I could identify the precise methods used to extract the cassiterite and to recognize earthworks of different dates. Much has yet to be achieved regarding the absolute dating of the tinworks, but pollen analysis near the Colliford tin mill indicated that at least part of the tin streamwork was abandoned before 600 to 700 A.D. Many of the surviving streamworks in the southwest of England will be much more recent than this, as most probably belong to the late medieval period (1300 to 1500).

The scrutiny of streamwork earthworks has been the most productive aspect of the detailed survey of tinworking remains, but other types of tinwork lend themselves to this form of examination to a greater or lesser extent. Analyses of the surface workings associated with early forms of mining--including the shallow shafts known as lode-back pits and the opencast quarries known as openworks or beams--have provided a valuable insight into the earliest forms of mining. Together with investigations of the contemporary documentation, the surveys have allowed us to build a remarkable picture of the industrial, technological, and social character of early tin exploitation in Britain.

Sandy Gerrard is a designation archaeologist for English Heritage. He has directed several archaeological excavations and surveys and has published extensively on the early tin industry.


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Name: From the Anglo-Saxon tin, named for the Etruscan god Tinia. The symbol is from the Latin word for tin, stannum.
Atomic mass: 118.71.
History: Known to ancient civilizations.
Occurrence: Often found as tin oxide, also called cassiterite. The metal can be isolated by heating the ore in the presence of carbon.
Appearance: Silvery white metal. Two known allotropes are white tin, which is metallic and malleable, and gray tin, which is brittle and powdery.
Behavior: Resists corrosion. Trialkyl- and triaryltin compounds are toxic.
Uses: Often used as a protective coating on other metals. Tin is alloyed with various metals to make foil, cans, solder, and pewter. Because it melts at a fairly low temperature, tin is ideal for casting. Bronze, an alloy of 80% copper and 20% tin, was used in ancient times to make tools and decorations. Stannic oxide and stannic chloride are used to make ceramic glazes and fabric treatments. Tin is also a major player in the Pilkington process for making glass panes.

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