Mesothermal lode gold deposits, typified by the Golden Mile, Kalgoorlie
Archaean conglomerate hosted gold-uranium deposits, typified by Elliot Lake, Canada and Witwatersrand, South Africa
Carlintype gold deposits, including;
Epithermal stockwork vein deposits
The basic extraction of ore deposits follows these steps:
Prospecting or exploration to find and then define the extent and value of ore where it is located ("ore body")
Conduct resource estimation to mathematically estimate the size and grade of the deposit
Conduct a pre-feasibility study to determine the theoretical economics of the ore deposit. This identifies, early on, whether further investment in estimation and engineering studies is warranted and identifies key risks and areas for further work.
Conduct a feasibility study to evaluate the financial viability, technical and financial risks and robustness of the project and make a decision as whether to develop or walk away from a proposed mine project. This includes mine planning to evaluate the economically recoverable portion of the deposit, the metallurgy and ore recoverability, marketability and payability of the ore concentrates, engineering, milling and infrastructure costs, finance and equity requirements and a cradle to grave analysis of the possible mine, from the initial excavation all the way through to reclamation.
Development to create access to an ore body and building of mine plant and equipment
The operation of the mine in an active sense
Reclamation to make land where a mine had been suitable for future use
Although the history of tempera (pigment mixed with either egg whites or egg yolks, then painted on a plastered section) and related media in Europe indicates that oil painting was discovered there independently, there is evidence that oil painting was used earlier in Afghanistan. Outdoor surfaces and surfaces like shieldsboth those used in tournaments and those hung as decorationswere more durable when painted in oil-based media than when painted in the traditional tempera paints.
Most Renaissance sources, in particular Vasari, credited northern European painters of the 15th century, and Jan van Eyck in particular, with the "invention" of painting with oil media on wood panel supports ("support" is the technical term for the underlying backing of a painting). However, Theophilus (Roger of Helmarshausen?) clearly gives instructions for oil-based painting in his treatise, On Various Arts, written in 1125. At this period, it was probably used for painting sculptures, carvings and wood fittings, perhaps especially for outdoor use. However, early Netherlandish painting in the 15th century was the first to make oil the usual painting medium, and explore the use of layers and glazes, followed by the rest of Northern Europe, and only then Italy.
Early works were still panel paintings on wood, but around the end of the 15th century canvas became more popular as the support, as it was cheaper, easier to transport, allowed larger works, and did not require complicated preliminary layers of gesso (a fine type of plaster). (This style was known as a fresco painting: applying gesso, then painting over with tempera paint) Venice, where sail-canvas was easily available, was a leader in the move to canvas. Small cabinet paintings were also made on metal, especially copper plates. These supports were more expensive but very firm, allowing intricately fine detail. Often printing plates from printmaking were reused for this purpose. The popularity of oil spread through Italy from the North, starting in Venice in the late 15th century. By 1540, the previous method for painting on panel (tempera) had become all but extinct, although Italians continued to use chalk-based fresco for wall paintings, which was less successful and durable in damper northern climates.