In the 4th century BC Plato knew oreichalkos as rare and nearly as valuable as gold and Pliny describes how aurichalcum had come from Cypriot ore deposits which had been exhausted by the 1st century AD.

In Europe, the major source for tin was Great Britain's deposits of ore in Cornwall, which were traded as far as Phoenicia in the Eastern Mediterranean.

* Channel-iron deposits, one of the major sources of saleable iron ore

Some calderas are known to host rich ore deposits.

The country has deposits of coal, opal, gemstones, kaolin, iron ore, soda ash, and tantalum, but only gold is mined in significant quantities.

Afghanistan is endowed with a wealth of natural resources, including extensive deposits of natural gas, petroleum, coal, marble, gold, copper, chromite, talc, barites, sulfur, lead, zinc, iron ore, salt, precious and semi-precious stones, and many rare earth elements.

A proposed third stage would continue the line from Booué to Belinga in the northeast, where there are iron ore deposits.

Possible projects at the time included extending a line from Ejisu to Nkoranza and Techiman ; a line from Tamale to Bolgatanga and Paga to Burkina Faso ; a line from Wenchi, Bole to Wa and Hamile and also to Burkina Faso, and a line to Yendi where there are iron ore deposits.

Guinea is richly endowed with minerals, possessing an estimated quarter of the world's proven reserves of bauxite, more than 1. 8 billion metric tons ( 2. 0 billion short tons ) of high-grade iron ore, significant diamond and gold deposits, and undetermined quantities of uranium.

Concession agreements have been signed for future exploitation of Guinea's extensive iron ore deposits.

Guinea is richly endowed with minerals, possessing an estimated one-third of the world's proven reserves of bauxite, more than 1. 8 billion metric tons ( MT ) ( 2. 0 billion short tons ) of high-grade iron ore, significant diamond and gold deposits, and undetermined quantities of uranium.

Many large granite plutons are the sources for palaeochannel-hosted or roll front uranium ore deposits, where the uranium washes into the sediments from the granite uplands and associated, often highly radioactive, pegmatites.

A major source of zircon ( and hence hafnium ) ores are heavy mineral sands ore deposits, pegmatites particularly in Brazil and Malawi, and carbonatite intrusions particularly the Crown Polymetallic Deposit at Mount Weld, Western Australia.

The heavy mineral sands ore deposits of the titanium ores ilmenite and rutile yield most of the mined zirconium, and therefore also most the hafnium.

It included hydraulic mining to prospect for ore by removing overburden as well as work alluvial deposits.

The country ’ s huge iron ore deposits were made accessible to commerce.

Limestone, clay, sand, and gravel are Lithuania's primary natural resources, but the coastal shelf offers perhaps of oil deposits, and the southeast could provide high yields of iron ore and granite.

Sulfides are susceptible to weathering, and many readily dissolve in water ; these dissolved minerals can be later redeposited, which creates enriched secondary ore deposits.

To take advantage of the country's sizable iron ore deposits in Zouerate, the new government built a 675-km railway and a mining port.

Mauritania has extensive deposits of iron ore, which account for almost 50 % of total exports.

They used similar methods to work cassiterite deposits in Cornwall and lead ore in the Pennines.

Surface mining is done by removing ( stripping ) surface vegetation, dirt, and if necessary, layers of bedrock in order to reach buried ore deposits.

Techniques of surface mining include ; Open-pit mining which consists of recovery of materials from an open pit in the ground, quarrying or gathering building materials from an open pit mine, strip mining which consists of stripping surface layers off to reveal ore / seams underneath, and mountaintop removal, commonly associated with coal mining, which involves taking the top of a mountain off to reach ore deposits at depth.

Sub-surface mining consists of digging tunnels or shafts into the earth to reach buried ore deposits.

The method is similar to cut and fill mining with the exception that after being blasted, broken ore is left in the stope where it is used to support the surrounding rock and as a platform from which to work.

This allows for greater recovery as less ore is left behind in pillars.

He left Tombstone to find more ore and when he returned four months later, Gird had lined up buyers for their interest in the Contention claim, which they sold for $ 10, 000.

Both highly magnetic magnetite and slightly magnetic ilmenite ( titanium ore ) grains can be found be found in patches of black sands left along the beach of the main swimming area.

On that day, the first iron ore cars left Agate Bay early in the morning, along with a caboose for President Tower to ride in on the return trip.

Zelienople is situated on the left bank of the Connoquenessing Creek, in an area that is rich with coal and iron ore.

Mining of banded iron formations involves coarse crushing and screening, followed by rough crushing and fine grinding to comminute the ore to the point where the crystallised magnetite and quartz are fine enough that the quartz is left behind when the resultant powder is passed under a magnetic separator.

The left picture illustrates the fining process to make wrought iron from pig iron, with the right illustration displaying men working a blast furnace of smelting iron ore producing pig iron, from the Song Yingxing | Tiangong Kaiwu encyclopedia, 1637

By 1912, ore production had dropped to $ 5 million and the largest mining company left town in 1919.

Tailings, also called mine dumps, culm dumps, slimes, tails, refuse, leach residue or slickens, are the materials left over after the process of separating the valuable fraction from the uneconomic fraction ( gangue ) of an ore. Tailings are distinct from overburden, which is the waste rock or materials overlying an ore or mineral body that are displaced during mining without being processed.

As in most mines, the tailings, waste left over from processing ore, are a problem, and as of 2006, there are no plans to clean up the tailings.

Henry Tompkins Paige Comstock was left in their stead to care for the Grosh cabin and a locked chest containing silver and gold ore samples and documents of the discovery.

In 1663 the Brassington manor court forbade miners from taking water from the village well to wash ore, on pain of a fine of 1 /-, and in 1670 imposed fines of 3 / 4d on miners who left shafts uncovered or raised heaps of soil and waste minerals against fences, allowing cattle to climb over them.

Tailings ( the materials left over after the removal of the uneconomic fraction ( gangue ) of the ore ) also provide some of the archaeological evidence from Otago gold mine sites.

The Treffry Tramways were eventually built from Newquay to St. Dennis with the branch line to East Wheal Rose, and the first load of ore left East Wheal Rose on 26 February 1849 in horse-drawn tubs.

Although some ore is said to have been left standing in the mine, it does not seem likely that the mine will reopen.

The old miners were very thorough in their working and rarely left much ore for later generations.

The tramline which transported ore from the mine down the mountainside to the mill was purchased in the auction but the buyer left it and it still stands.

They are currently ( May 2006 ) road-training haematite fines (< 6 millimetres particle size ) left over as waste from the 1966-1974 Western Mining iron ore operation.

The building is actually an iron smelter left over from the 18th century when the ore was common in the area and needed for the Continental Army in the American Revolutionary War.

* Tailings, the material left over after the extraction of ore from its host material

The ore was probably crushed on the famous Carreg Pumsaint, a block of stone erected many years ago after the Romans had left the site.

( The term " sieve " is seen as alluding to, say, sifting ore for gold: we " sift out " the integers falling in one of the forbidden congruence classes modulo p, and ask ourselves how much is left at the end.