Best Mining Solutions For Everyone, Get a Free Quote.
Need A High Quality Mining Machine For Your Project?Contact With Us
You May Also Like
EPA developed this graphic to provide users of TRI data with a better understanding of mining operations and related TRI-reportable chemical releases. The metal mining sector handles large volumes of material and each year, this sector reports the largest total quantity of releases of TRI-covered chemicals (mostly in the form of waste rock) of any industry sector covered by the TRI Program. Consequently, this sector greatly influences the TRI data viewed by the public, driving several important national and local trends. For these reasons, EPA is explaining the metal mining sector’s TRI data in more detail. In the future, EPA may profile other important TRI industry sectors
Blasting frequency varies from mine to mine with some blasting occurring several times a day to once or twice a week. The blasting process begins by drilling holes into hard rock. The holes are then filled with blasting reagents (mixed at the blast hole) and ignited with blasting caps. The blasting generates rock and particulate matter (for example, dust) that have varying concentrations of TRI chemicals generally in the form of metals/metal compounds present in the ore and waste rock (for example, compounds of arsenic, copper, lead, mercury, zinc) and chemicals related to the explosives (for example, compounds associated with fuel oil used as reagents).
Once the ore (metal-bearing rock) and waste rock have been blasted into smaller blocks and fragments, mining facilities use excavators to remove the ore and waste rock from the ground and load the ore and waste rock into haul trucks for transport out of the mine pit. Ore and waste rock removal operations can generate particulate matter (i.e., dust) that contains TRI chemicals
Ore is transported from the mine pit by haul trucks capable of carrying up to 400 tons to either the Crushing and Grinding section of the mine (Step 5) or directly to the Leach Pad (Step 7). Ore transportation operations can generate particulate matter (i.e., dust) that contains TRI chemicals
In general, a sizeable portion of the rock that is blasted contains insufficient concentrations of target metals to economically process at any given time. This low-grade rock is called “waste rock” and normally must be removed from the mine to allow access to the ore-grade rock (i.e., rock that contains sufficient concentrations of target metals to economically process). The excavated waste rock is transported from the pit in haul trucks and then may be placed in “waste rock piles.” These waste rock piles are subject to engineering controls and regulations and are typically located within the boundaries of the mining facility. Waste rock may also be used for backfilling previously mined portions of the pit or for construction of roads on facility grounds.
Copper mining was extensive in the Keweenaw. As in, every city and town on the Keweenaw has its origins in the copper mining industry extensive. Copper mining formed the backbone of the economy here and similarly, copper deposits were found along the spine of the peninsula. The majority of copper mined here was native copper, 99.99% pure copper. Fortunately, this means that the waste products of mining here were more benign than in other parts of the world—but there still are long lasting environmental impacts
The main byproducts of copper mining in the Keweenaw were waste rock piles from the mines, tailings from the stamp mills and slag piles from the smelters. Waste rock piles, locally called poor rock, once dotted the landscape, accompanying every shaft of every mine. These piles have slowly disappeared, as the poor rock is a cheap and readily available material to be used in road construction. The sand and silt from the stamp mills, stamp sands, were often directly deposited into waterways in very large volumes
It is these stamp sands and associated materials that have caused the most severe environmental hazards. Indeed, in 1986 a Superfund Site was established that includes Torch Lake, the western shore of Torch Lake, the northern portion of Portage Lake, the Portage Lake Canal, Keweenaw Waterway, North Entry to Lake Superior, Boston Pond, and Calumet Lake. These areas were home to milling and smelting activities for over 100 years. During that time, the waterways served as dumping grounds for virtually all mining industry related waste products produced, including tailings, slag, and various chemicals. It is estimated that around fifty percent of the Torch Lake's volume was filled with 200 million tons of tailings and other waste products
Mining activities continued until 1968 around Torch Lake and shortly afterwards environmental concerns arose over the use of the lake as a dumping grounds. Fish were found with cancerous tumors and high levels of copper, arsenic, mercury and PCBs were found within the lake and the mine tailings. Because of these hazards the area was listed as a Superfund Site and remediation efforts were conducted. Some areas were capped with soil and revegetated, in places heavily contaminated soil and drums containing toxic material were removed, and other areas were left to recover naturally
After remediation the site was removed from the national priorities list, as human health is thought to have been adequately protected by the actions taken, but the area remains a Michigan Department of Environmental Quality Area of Concern. Torch Lake has been left to recover through natural sedimentation, which means that the lake bottom still has high levels of toxic metals that severely impact bottom-dwelling organisms and that fish in the lake have elevated PCB and mercury levels to the point that they should only be eaten in very limited quantities
For stamp sand deposits on Lake Superior itself, no remediation efforts were conducted as the erosive power of the lake makes stabilization efforts all but futile. Some of these deposits are quite extensive, with the sands near the town of Gay now covering over 5 miles of shoreline. These sands are also starting to work their way into the bay, where within 10 years they may cover 60% of Buffalo Reef, an important White Fish and Lake trout spawning area
Copyright © 2021 Facdori Machinery All rights reservedSitemap