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revegetation effort. Seed was broadcast onto the surface of the <br /> facility, which in some places was muddy from snow melt, while <br /> north facing slopes held about two inches of snow cover. <br /> Approximately 200 pounds of seed were broadcast over an estimated <br /> fourteen acres of the facility. No surface preparation or mulching <br /> was undertaken. <br /> Revegetation Experiments <br /> Results of 1995 revegetation experiments at Mine 4 were <br /> qualitatively analyzed during the 1996 field season. In 1995 four <br /> different mine bench outslope revegetation experiments were <br /> initiated: hydroseeding and mulching the slopes, hydroseeding and <br /> mulching artificial benches built on the slopes, hand seeding of <br /> artificial benches built on the slopes, application of soil guard <br /> on the slopes. <br /> Quantitative analyses have not been made, however visual <br /> observation indicates that the hydroseeding of the mine bench <br /> outslopes was fairly unsuccessful. It is thought that the seed and <br /> mulch applied to the outslopes is washed or possibly blown off the <br /> unprotected slopes before root establishment. In 1995, <br /> hydroseeding was accomplished on the north and east outslopes at <br /> Mine 3 and on the north and east slopes at Mine 4. By the end of <br /> the 1996 construction season, growth on the north slope of Mine 3 <br /> could be observed from the Mine 5 fan. However, little, if any, <br /> growth was observed at Mine 4. It is thought that the north side <br /> of Mine 3 bench is more sheltered from wind, allowing seed an <br /> opportunity to germinate before being blown off the outslope. <br /> Growth on the artificial benches was about equally distributed <br /> between the hydroseeded and hand seeded benches. Stands of grass <br /> were observed on benches at both sites. Construction of the <br /> benches on the steep outslopes is very difficult and time <br /> consuming, however. A failing of the benches is that they appear <br /> susceptible to significant erosion at their margins, thus <br /> indicating a short lifespan. This technique alone does not appear <br /> adequate to achieve any significant degree of outslope stability. <br /> An approximately one half acre area was treated with Soil Guard, <br /> which is an organic glue-like substance which adheres to the slope <br /> surface, thus holding soil particles in place. It is applied from <br /> a hydro mulch unit. The test area was fertilized and hand <br /> broadcast seeded prior to application of the soil guard. The test <br /> area exhibited the best vegetation results of all test plots. The <br /> area treated with Soil Guard also appeared to be more resilient to <br /> erosion than adjacent, untreated areas. This method of erosion <br /> control and revegetation is recommended based upon visual <br /> observations. However, the price of $5,000 to $7,000 per acre <br /> installed is probably prohibitively expensive. <br /> In 1996, a new method of revegetating steep mine bench outslopes <br /> was tried. The modified roller discussed in the Mines 1 and 2 <br /> summary was utilized on the south and east facing outslopes of Mine <br /> 17 <br />