Permafrost by permafrost. Of this area slightly more than half is underlain by continuous permafrost, around 20 percent by discontinuous permafrost, and a little less than 30 percent by sporadic permafrost. Most of this area is found in Siberia, northern Canada, Alaska and Greenland. Beneath the active layer annual temperature swings of permafrost become smaller with depth. The deepest depth of permafrost occurs where geothermal heat maintains a temperature above freezing. Above that bottom limit there may be permafrost, whose temperature doesn't change annually—"isothermal permafrost". Permafrost typically forms in any climate where the mean annual air temperature is less than the
Jericho Diamond Mine On July 19, 2010 Shear Diamonds (née Shear Minerals Ltd) (), a diamond exploration company focused on the Nunavut region, announced its purchase of the Jericho Diamond Mine. In late 2010, Shear announced that it would take about a year to devise a plan to reopen the mine. Shear began processing the existing recovery reject pile in early 2012, selling the recovered stones to Belgian diamond firm Taché, which provided a revolving line of credit. However, operations were suspended in September, as Shear, citing "limited funds and significant operations", has sought to minimize expenditures. Taché has given notice of default