2012-10-01_REVISION - M1977310 ‎(10)‎

• Permit No: M1977310
• IBM Index Class Name: REVISION
• Doc Date: 10/1/2012
• Doc Name: EPP
• From: Cotter
• To: DRMS
• Type & Sequence: AM1
• Media Type: D
• Archive: No

JD -6 Mine Environmental Protection Plan 24
7.3 Storm Frequency
The rainfall intensities for the 24 -hour storm with a 2 -year to 100 -year recurrence interval were interpolated
from the NOAA Atlas 2, Vol. III, for the purpose of runoff calculations and engineering design. The
magnitude of the design storms is shown in Table 14.
Table 14. Rainfall Intensity at the JD - 6 Mine
Duration
(Hours)
24
24
24
44
24
24
(
)
Recurrence
Interval
100 -year
50 -year
25 -year
10 -year
5 -year
2 -year
Storm Magnitude
NOAA Atlas
inches
3.0
2.7
2.4
2.0
1.6
1.2
7.4 Temperature
Temperatures at the Uravan NWS meteorological station generally range from 48 to 96 °F in the summer,
and from 16 to 59 °F in the winter. The temperature data collected at the private meteorological station at
the Pinon Ridge Mill site from May 2008 to March 2009 are consistent with the Uravan temperature
ranges. The overall average annual temperature at Uravan is 53.2 °F (Table 10) while the average
temperature at the Pinon Ridge Mill site for the period of record from May 2008 to March 2009 was 51.6
°F.
7.5 Wind Speed
Wind speed data are not available for most meteorological stations in the area (Table 9). Short -term wind
speed records are available from the private meteorological station at the Pinon Ridge site located
approximately 3 miles from the JD -6 mine. Wind speed and direction was recorded hourly at the Pinon
Ridge Mill site from April 2008 to March 2009 (Kleinfelder, 2009). Generally, daytime westerly winds
with higher speeds (approximately 8 mph) were observed in April, May, and June of 2008 and in March of
2009. Calm night -time southeasterly breezes were observed in all months, but the calmest conditions were
recorded in the months of November and December 2008 and January and February 2009 (Kleinfelder,
2009).
Longer term wind speed records are available from the Bureau of Land Management (BLM) Remote
Automatic Weather Station (RAWS) in Nucla, Colorado. Based on the available data for the Nucla station
from 1999 through 2010, the average annual wind speed is 5.1 mph (Table 15) with maximum recorded
wind gusts up to 76 mph (Table 16).
4148A.120927 Whetstone Associates