Laserfiche WebLink
4.05.8 Acid-forming and Toxic-formi~tg Spoil <br />Acid-forming materials do not exist within the overburden to be removed <br />by the mining operations. A discussion on the overburden at the Colowyo <br />operation has been conducted as set forth in Section 2.04.6. A <br />discussion of the overburden monitoring plan is set forth in Section <br />2.05. <br />4.05.9 Permanent and Tempor~ Impoundments <br />Colowyo intends to construct a number of small depressions on reclaimed <br />areas. These small depressions are essential and basic to the management <br />of the rangeland post-mining land use of livestock grazing and wildlife <br />habitat. The design of the depressions provides for structures having a <br />vertical height less than five feet from the bottom of the channel to the <br />bottom of the spillway and impound less than two acre feet of water. As <br />such they are exempt from Division of Water Resources, Office of State <br />Engineer requirements. water harvesting ditches may also be used to <br />enhance the function of the depressions, which is consistent with <br />practices employed on adjacent rangelands. The location of the <br />depressions is shown on Map 12 - Hydrology - South and other information <br />is provided in Exhibit 7, Item 16 Small Depressions/Tanks. <br />The depressions collect surface runoff from precipitation events and <br />snowmelt from reclaimed areas. The depressions do not result in the <br />diminution of the quality or quantity of water for downstream water <br />users. Colowyo is the holder of water rights immediately downstream. <br />During periods of low precipitation the impoundments may be dry, which <br />is consistent with regional practices on similar rangelands. Since the <br />source of water is surface runoff from revegetated areas the quality of <br />the water will meet the requirements of the intended use. <br />The depressions have areas of 4h:ly slopes or less to provide easy access <br />to both livestock and wildlife. These depressions and any associated <br />ditches, while intended to be permanent, will be classified as temporary <br />until the requirements of Rule 4.05.9. are met. Prior to construction, <br />all designs. are submitted..to the Division. A copy of the as-built design <br />information will be submitted after construction for inclusion into <br />Exhibit 7, Hydrology. In addition, sedimentation ponds that are <br />subsequently approved as part of the post-mining land use, as shown on <br />the Hydrology - South Map (Map 12), will remain as permanent impoundments <br />after the requirements of Rule 4.05.9 have been met. <br />All embankments, impoundments and associated structures will be <br />revegetated if construction materials are conducive to plant growth. <br />Routine inspections of these structures will also be conducted <br />4. 5-8 <br />Revision submitted 7- I.5 9 <br />Revision ~. m R - s ~ <br />