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The next structure tested (Type II), was the culvert <br />underpass. Three corrugated culverts (CUP-1- CUP-3) were <br />buried beneath the access road and conveyor belt line at key <br />locations parallel to natural drainages that ran <br />perpendicular to the belt. These structures were only 1.4 <br />meters wide and 2.4 meters in height. Reed (et al. 1975, <br />Reed 1981, Ward 1978) found mule deer used highway <br />underpasses with different degrees of success. These <br />highway underpasses were typically 3.05 meters high and 3.05 <br />meters wide. He also recommended that the area be fenced to <br />the approach of each underpass, in order to herd the animals <br />toward each underpass. Deserado Mine culvert underpasses <br />were 1.7 meters narrower and 0.6 meters shorter than Reeds <br />(1975) recommendation. Also, approach areas were not fenced <br />in order to funnel animals toward them. <br />Consequently, total track counts for animal passage were <br />minimal with a total of only 2 Elk passages (One cow and <br />calf), 4 Mule Deer (Does and fawns), and no Pronghorn <br />Antelope passages. However, numerous Nuttall's cottontail <br />rabbit (Sylvilagus nuttallii ) tracks were noted as well as <br />the following predator passages during the study - 3 Coyotes <br />(Canis latrans ), 2 Mountain Lion (Fe1is concolor ), and 1 <br />Bobcat (Fe1is rufus). This crossing type appeared to be <br />important for predator passage by providing addittional <br />cover in order for the predator to pass beneath the conveyor <br />beltline undetected. During one track count transect, the <br />author observed a single coyote hunting field mice beneath <br />the beltline structure near conveyor underpass number 4 (UP- <br />4). Only one of the three culvert underpasses had an <br />earthen floor installed and the big game animals seemed to <br />avoid walking on corrugated culvert floor due to unsure <br />footing problems. All three culvert underpass structures <br />were located parallel to natural drainages that crossed <br />beneath the belt line access road. <br />The third type of passage structure installed at the mine <br />was the beltline underpass.(Type III). Five conveyor <br />underpass structures were installed. Four of the structures <br />were designed for vehicle traffic under the belt line, with <br />one structure (UP-4) installed specifically as a big game <br />underpass. At this location a 46 meter length of beltline <br />was elevated to 2.1 meters in height and a maximum width at <br />the center of 6.1 meters. Dimensions for all the conveyor <br />underpass structures can be found in Table 8. This type of <br />crossing was utilized by all three big game species at the <br />Deserado mine site. <br />The conveyor beltline at the mine was elevated to a <br />average of 0.8 meters along the entire length between <br />passage structures. This provided additional passage <br />availability to the migrating big game. Dimensions for the <br />beltline are found in Table 10. Dalton (1984) recommends <br />that a minimum of 1.0 meter be used for underpasses for mule <br />