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List of State Officials - Martin O'Malley, Governor; Anthony Brown, Lt. Governor; Shari T. Wilson, MDE Secretary 

Volume IV, Number 3

 February 2010

eMDE is a quarterly publication of the Maryland Department of the Environment. It covers articles on current environmental issues and events in the state. 

Proposed Renewal of General NPDES Permit for Mineral Mines

By Patsy Allen, Water Management Administration

Back to this issue's cover page 

The Maryland Department of the Environment is revising and reissuing the General Permit for Discharges from Mineral Mines, Quarries, Borrow Pits, and Concrete and Asphalt Plants.

Reissuance of this permit will be an important step forward in providing increased protection to waters of the state from industrial sources of sediment and in addressing the Department’s discharge permit backlog.

More than 200 mines in Maryland are currently covered by the general NPDES (National Pollutant Discharge Elimination System) permit. The proposed renewal for this category of industrial dischargers includes more stringent effluent limitations for total suspended solids, particularly in wet weather, in part because a number of waterways in Maryland are impaired by excessive sediments. Further restrictions apply to new facilities if they propose to discharge to streams on the State's 303(d) list for impaired waters or to streams for which total maximum daily loads have been established for sediment.

The proposed permit also includes toxicity reporting of additives used in concrete. Concrete is modified with a number of additives to improve building and setting characteristics, and the proposed new permit requires monitoring of the effluent from concrete plants to make sure the addition of these chemicals does not cause toxicity to aquatic life.
Like the existing permit, the proposed renewal requires the implementation of a stormwater pollution prevention plan to minimize the exposure of stormwater entering and leaving the property to any sources of pollutants. These plans will be accessible to the public.

A notice of tentative determination for the permit was published in the Maryland Register on November 6, 2009, and a public hearing was held in December. Numerous comments were received from industry groups concerned about additional requirements in the permit. A notice of final determination will be published prior to the issuance of the permit, explaining any changes to the draft general permit.

For more information go to General Discharge Permit For Discharges from Mineral Quarries, Borrow Pits, and Concrete and Asphalt Plants


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Editorial Board
Maryland Department of the Environment
1800 Washington Boulevard, Baltimore, MD 21230