2011-06-30_REVISION - M2002004 (82)

Home Browse Search

GCC Rio Grande, Inc. — Pueblo Cement Plant and Limestone Quarry Exhibit E Mulching & Cover Crops Various types of mulching or cover crops may be used to facilitate the establishment of permanent vegetation communities. Three primary mulch types may be used at the mine to facilitate germination and establishment of suitable vegetation covers including native hay or straw mulch, hydromulch or a cover crop. Omitting the mulching process is also an option when conducting permanent vegetation planting operations. Native Hay or Straw When mulch is used, the preferred type will be native hay, with agricultural cereal straw being second. Native hay or straw mulch will be applied at a targeted rate of 2 tons per acre. Native hay or straw mulch materials will be evenly and uniformly distributed over the treatment site. Mulch may be spread either by hand or equipment. Mulch materials will be certified weed -free. Mulch materials will be free of mold and fungus. At least 50% of the mulch material by weight will be equal to or greater than 10 inches in length. After application the mulch will be crimped or adequately tacked (normally at least 80 pounds of R -tack per acre). When used, mulch will be applied as soon as is practicable following completion of seeding activities. Care will be taken to spread mulching machinery traffic across the planted surface and multiple trip passes along a single route avoided, in an effort to avoid excessive soil compaction. Hydromulching Hydromulching may be used on slopes where it is impracticable to conduct traditional hay or straw mulching, or when hay or straw is not available in the market place. Hydromulch will be applied at a rate of 1 ton per acre with a minimum of 100 pounds of R -tack per acre. A hydromulcher that is capable of accessing the terrain to be treated will be used for this operation. Cover Cropping A cover crop may be established prior to seeding the permanent rangeland seed mixture or it may be seed concurrently with it. Sterile Triticale will be used to establish a cover crop or short term vegetation cover. (i.e., dust control purposes, soil stabilization, etc.). The cover crop may be left standing, mowed or plowed under depending upon the timing of planting the permanent seed mixture. It may either be frilled or broadcast, but drilling is the preferred method for this species. It will be seeded at the rate of 20 pounds per acre when used as a cover crop for establishing the permanent seed mixture and will be applied separately and prior to the permanent seed mixture. When used for short term cover, the seeding rate should be 30 pounds per acre. No Mulch Option Recent data on arid and semi -arid native prairie rangeland restoration projects suggests that mulching may not always be a desirable component in the reclamation process, particularly when rock is present in the topsoil. Mulch may contain noxious or other weedy species that are detrimental to establishment of the desired plant species and vegetation communities (even when certified weed - free). While mulch shades the ground and inhibits evaporation of soil moisture, it also intercepts and absorbs precipitation, thus preventing some precipitation from entering the soil profile. The drier the climate, the more important interception and absorption of precipitation by mulch become. Additionally, recent test plot data suggests that use of mulch may inhibit expression of seed mixture species diversity. For these reasons, GCC may selectively choose whether or not to apply native hay, straw or hydro mulches based on the site conditions associated with reclamation areas each year. Revised June 29, 2011 E -6 Exhibit E — Reclamation Plan