Absorbed. The encorporation of a compound in solution within a mineral structure.

Acid mine drainage. The general term applied to water being discharged from a mine, a tailings pond or leaching through a mine spoil dump. Most mine drainage is acidic, but can also be either neutral or even alkaline. Mine drainage can carry a significant level of metals in solution.

Adit. A tunnel driven into a hillside to facilitate access, drainage and haulage of ore to the surface from a mine.

Adsorbed. The attraction of compounds in solution to a mineral surface.

Aggregates. Particles of rock that are used in a bound or unbound form in construction.

Arsenate. An inorganic form of oxidised arsenic (As5+).

Arsenite. An inorganic form of arsenic which is partially reduced (As3+).

Arsenopyrite. The main ore mineral for arsenic (FeAsS).

Basaltic. A fine grained igneous rock composed of the minerals plagioclase and pyroxene.

Bedload. Sediment grains transported at the base of a river etc where the grains are moving by either rolling, sliding or saltation (bouncing).

Blowing houses. A building in which tin was smelted with charcoal in a stone built furnace served by bellows operated by a water wheel.

Cassiterite. The major ore mineral for tin (SnO2)

Chalcopyrite. The major ore mineral for copper (CuFeS2).

China clay. A soft white, plastic clay composed of the mineral kaolinite. China clay is an important industrial mineral as a paper liner, ceramics, cosmetics etc.

Clay grain size fraction. These are sediment grains which are less than 4 microns in size.

Copepods. Small aquatic crustaceans of the Class Copepoda.

Crustaceans. An arthropod belonging to the class Crustacea, having a hard external shell.

Devensian glaciation. The last major glacial climatic interval to have affected the Northern Hemisphere, from about 122,000 before present through to 10,000 years before present. During the Devensian glaciation, glaciers did not reach as far south as Cornwall, but the area did have periglacial conditions.

Devonian. Part of the Palaeozoic geological time scale ranging from 410 to 355 million years ago.

Eutrophic conditions. When water becomes very nutrient-rich (through sewage release etc), there is a sudden increase in the growth of micro organisms (e.g. algae) causing the water to become oxygen-starved.    

Famennian. The Devonian period of Earth history is divided up into seven stages, which are, from oldest to youngest: Lochkovian, Pragian, Emsian, Eifelian, Givetian, Frasnian and Famennian. Thus the Famennian is the youngest part of the Devonian.

Fe hydroxides. Hydroxides are metallic compounds containing oxygen and hydrogen either in the form of the hydroxide ion (OH-) or the hydroxyl group (-OH), such as the iron mineral goethite.

Foraminifera. An order of single celled protozoans.

Frasnian. The second to last stage of the Devonian.

Galena. The major ore mineral for lead (PbS).

Gangue minerals. The unwanted, or waste minerals or rock with which the economically important minerals occur. For example, in Cornwall, the cassiterite will commonly occur associated with quartz and toumaline in the mineral veins.

Granite. A coarse grained igneous rock composed of quartz (over 20%) and feldspar in which plagioclase and alkali feldspar occur in approximately equal proportions. A series of granite masses occur forming the "spine" of south-west England ranging from the Isles of Scilly in the West to Dartmoor in the east. Two important granites are present around the Fal Estuary - the Carnmenellis Granite and the St. Austell Granite.

Hard rock mining. Underground mining operation, usually for metal.

Head deposits. A term for sediments formed through a range of slope processes under periglacial conditions first used by De La Beche in 1839 for deposits in SW England. Head deposits are generally composed of a clay matrix with a wide range of sizes of angular rock fragments.

Hydrothermal. A mineral deposit where the economically important minerals have precipitated from a hydrothermal (hot water) solution.

Industrial minerals. An industrial mineral is a geological material obtained by mining which is a non-metallic, non-fuel raw material of commercial value.

Intertidal mudflat. Areas of accumulated sediment, dominantly of a clay or silt grain size exposed at low tide.

Liberated grains. During mineral processing the aim is to separate the economically important ore minerals from the associated waste, or gangue, minerals. If this has been succesfully achieved and the sediment grain is only made up of the economically important mineral it is referred to as a liberated grain.

Lodes. A vein or fracture in which commercially valuable minerals have been deposited.

Macrotidal. Tidal ranges can be defined as the difference between mean high and mean low spring tides. Where the mean spring tide range is between 4 and 6 metres it is termed macrotidal.

Mesotidal. Tidal ranges can be defined as the difference between mean high and mean low spring tides. Where the mean spring tide range is between 2 and 4 metres it is termed mesotidal.

Metasedimentary. Originally sedimentary rocks which have been subsequently affected by the process of metamorphism.

Mineral processing. Mineral processing is a branch of engineering which focuses on separating minerals of value from the unwanted waste or gangue minerals. This may for example, be achieved simply on the basis of separating minerals of different densities.

Monazite. A rare earth phosphate mineral ((Ce,La, Y, Th)PO4) mineral which is common both as minor mineral component in granites and is also common in mineralised lodes in south-west England . Nematodes. Parasitic or free living worms assigned to the Phylum Nematoda, with a slender unsegmented cylindrical shape.

Ochre. Mixture of hydrated oxides of iron and manganese used as a filler in the manufacture of paints and some papers.

Ore minerals. Metalliferous minerals which can be exploited with a profit.

Periglacial. The term periglacial refers to the conditions, processes and landforms associated with cold, nonglacial environments.

Placer deposits. Naturally occurring localised concentrations of economically important ore minerals. Most placer deposits, like the cassiterite placers of south-west England are made up of dense, chemically and physically resistant minerals locally concentrated by natural processes.

Polychaetes. Aquatic annelid worms belonging to the Class Polychaeta, including for example lugworms and ragworms.

Pyrite. A very common iron sulphide mineral (FeS2).

Quaternary. The most recent interval of Earth history, extending from 1.8 million years ago through to the present day. The Quaternary is characterised by repeated extreme variations between glacial and inter-glacial climates.

Regional metamorphism. The large scale regional alteration of pre-existing rocks under elevated temperatures and pressures resulting from burial in the earths crust. All of the Devonian rocks of south-west England underwent regional metamorphism during a mountain building event known as the Variscan Orogeny.

Saltmarsh. Vegetated areas in the upper part of the intertidal zone of estuaries where salt tolerant plants grow between the high spring tide and the mid tide level. The enhanced siltation as a result of mining has increased the amount of saltmarsh around the upper reaches of the Fal Estuary.

Sediment accretion rate. The rate in mm per year at which sediment accumulates as a result of deposition. Sediment accretion rates in salt marsh areas can range between 10 cm and 0.001 cm per year, and are often enhanced as a result of human activity.

Siltation. The process of the deposition of sediment from water, other resulting in the loss of a port or harbour as seen in many parts of Cornwall.

Smelting. The extraction of metal from an ore mineral by melting.

Sphalerite. The major ore mineral of zinc (ZnS).

Spoil heaps. Localised deposits of waste rock material left close to a mine site.

Streamworks. The concentration of tin from naturally occurring sediments using water to separate the denser cassiterite from the less dense gangue minerals.

Subtidal. Areas in shallow coastal areas which are below the low tide mark.

Suspended. Sediment particles which are held buoyantly aloft within a flowing body of water as a result of the fluid turbulence.

Tailings. Particulate waste material produced during mining operations. Tailings are typically composed of the both the waste gangue minerals and also small grains of the economically important minerals which have not been recovered during mineral processing.

Tin streaming. The mining of cassiterite placer deposits with the separation of the denser cassiterite from the less dense gangue minerals.

Tributyltin. A chemical agent used in the past in shipping as an antifouling agent.

Wolframite. The major ore mineral of tungsten ((Fe,Mn)WO4).

Xenotime. A phosphate mineral which occurs in some igneous rocks (YPO4).

Zircon. A common minor mineral present in igneous rocks (ZrSi04).