The metal mining sector accounts for most of the Toxics Release Inventory (TRI) chemical waste disposed of to land. This graph shows the trend in the pounds of toxic chemicals disposed of to land at the reporting facility’s site.

Click to exclude metal mines from analysis

From 2005 to 2015:

• On-site land disposal decreased by 3% (from 2.07 to 2.01 billion pounds).
• Recent fluctuations are primarily due to changes in waste quantities reported to the TRI Program as “other land disposal,” which can include chemical waste disposed of in waste piles and spills or leaks.
• “Other land disposal” increased by 13%, while all other types of on-site land disposal decreased. Most of the toxic chemical waste reported as other land disposal is contained in waste rock at metal mines.
• Disposal to land is often regulated by other programs as well, such as under the Resource Conservation and Recovery Act (RCRA).

In 2015:

• Land disposal trends are largely driven by the metal mining sector, which accounted for 61% of land disposal quantities. Click the button under the figure above to view the land disposal trend with metal mines excluded from the analysis.
• Most of these quantities are made up of either lead and lead compounds (39%) or zinc and zinc compounds (33%).

Metal mining facilities typically handle large volumes of material. In this sector, even a small change in the chemical composition of the mineral deposit being mined can lead to big changes in the amount of toxic chemicals reported nationally. In recent years mines have cited changes in production of waste rock, changes in the composition of waste rock, and the closure of a heap leach pad as the primary reasons for the reported variability in land disposal of TRI chemicals. Changes in waste rock composition can have an especially pronounced effect on TRI reporting because of a regulatory exemption that applies based on a chemical’s concentration in the rock, regardless of total chemical quantities generated.

Federal and state agencies require that waste rock be placed in engineered structures that contain contaminants. Federal and state land management agencies also require that waste rock and tailings piles and heap leach pads be stabilized and re-vegetated to provide for productive post-mining land use.

For more information on waste management by the mining industry, see the Metal Mining sector profile.

This graph shows the trend in the pounds of toxic chemicals disposed of to land, excluding metal mining.

Click to include metal mines in analysis

From 2005 to 2015:

• Total on-site land disposal for all industries other than metal mining decreased by 14%.
• Disposal to landfills, which accounts for the greatest percentage of land disposal when metal mining is excluded, decreased by 16%.

In 2015:

• Excluding metal mining releases, chemicals disposed to land in the largest quantities are: barium and barium compounds (20%), manganese and manganese compounds (13%), and zinc and zinc compounds (11%).

While releases to land have decreased in many sectors, releases by metal mining drive overall land disposal trends. See the graphic, Land Disposal by Industry, for more information.