A new promising ore province, the Gold Line, southwest of the well-known Skellefte District, northern Sweden, is currently under exploration. This province hosts, so far, one operating mine, the Svartliden Au mine, and the recently closed Blaiken Zn-Pb-Au-Ag mine. The largest known gold deposit, the hypozonal Fäboliden orogenic gold deposit, in the area was recently granted mining permits. The deposit holds c. 54 Mt at 1.2 g/t Au, with a planned production of 4.6 Mt of ore/year.

Mineral exploration has long been an active pursuit of both individuals and mining companies in Ontario. In recent years there has been a resurgence of interest in prospecting by individuals as a full time occupation, but more especially as “weekend prospectors’’. Accordingly, it was thought appropriate to collect together the reported instances of mineralized fragments dislodged from their bedrock source so that the techniques of tracing such fragments to their source as well as the locations of known fragments would be available to those interested in mineral exploration. 

One of the first things discussed in an Introduction to Mining course and one which students must commit to memory is the definition of ‘ore’. One of the more common definitions (USBM, 1967) is given below:
Ore: A metalliferous mineral, or an aggregate of metalliferous minerals, more or less mixed with gangue which from the standpoint of the miner can be mined at a profit or, from the standpoint of a metallurgist can be treated at a profit.

Common challenges associated with grade uncertainty involve failing to meet decisive operational targets, which include (among others) the following: ore tonnage sent to the mill, total metal processed at the mill, blending requirements on ore feed, total waste tonnage mined, maximum allowable proportion of potentially deleterious materials (e.g., toxic elements such as arsenic). These challenges reflect, to an important extent, the uncertainty involved in defining precisely the mineral grades in an ore deposit. <...>