PERMFILE42872

• Permit No: M1994117
• IBM Index Class Name: Permit File
• Doc Date: 5/2/1995
• Doc Name: ADEQUACY REVIEW RESPONSE
• Media Type: D
• Archive: No

Gold Hill Mill Adeauaev Reviex Reeconae Mav 2, 199,E
2'7 a) The only available as-built topogmptuc rnfonnetion and sections were srnt to the Dtvtsion on Apri1:Y
1995 by Mark Steen of hli Vida Enterprmes. We have no documrnhetion on foundation charactetvtrcs
or foundatron atrrlice preperetion.
b) Dimetuiona oCthe existing stater dam as shown m plan and nose xctione from Mark Stem are
CreetElevatiorr NA
Crest Vl'idth: 10 to l1 feet normnel
Crest length. Approx. 370 feet
Upstream Slope Angle 1.6:1 to greats then 3: I
Downstream Slope Angle Appmx. 15' I
c) No information is currmily available on embankment materials. COM, Inc, will attempt to take
samples for enelysu as soon as weather conditrorts allow work on-site to restune. A report dated
November ti, [985 fiom Denver Engineering Corporation irtdieated that the tailings pond was
constructed to meet plans and speciflcelioro.
d) A construction discriptiod letter from Mr. Mark Steen, dated July 16, 1987 to the Division, lists the liner
as a 30 ttul polyethykate liner. A copy of the letter is attached. AIl flaws in the liner wdl be patched by
a qualified company by the end of Jtme.
e) The decant Ittte is a 2-inch HDPE Gne with three nears (oprn pipe kes) placed at equal distances along
the line. The line u about 230 feet long end is placed on top of the tarungs th the casts.[ pottdittg azea.
The pipe is connected to a 2-inch PVC standpipe that is I«ated at the south and of the pond. The
standpipe goes horizontally through the liner and embenluneru at the bottom of the pond. We have no
details on the standpipe as it goes through the liner or the emben{nttent The 2•trtch PVC pipe u buried
to a point just below the base of the embankment where a valve box is located. The 2•inrh PVC
pipeline then u laid vn the surface oC the ground down to the Haul A edit (see Exhibit A) where the
pipeline goes through a short urdirted borehole and uno the horizontal Hazel A edit. The pipeline
extends back from the portal approximately 30 feet where the pipebne discharges behind a wooden
bulkhead thst contains the water in the mine workings that are wnnected to the Time and Wynona
mines. Water hom Left Hand Creek is also pumped 3,900 feet through the 2vtclt pipeline located in
Akira Gulch and situated on property purchased by C.O.M. inc to a point north of County Roed No.
52 where the water line enter the portal of the Tune mine. A bulldtead u constructed in the Time [[tine
edit and water is discharged fiom the pipe into die Time mina worlangs behind the bulkkteed. The Time
nurse edit passes 45-feet below County Roed No. 52 end extends 393 feet ut a southeasterly dvection
where the 71me mine is connected with the Wynono mine by a SO-foot deep wiriZe. Both the Time and
W ynona nurses are bevtg wed to store water for milling operetiotu for the penod between November t
end May 31. Mill water u drean from the workirtga by pumping the wets out of the Wynona [rune
stall.
28. a) An upstream raise will not he used for reuutg the embartlartent TTie base of the starter dike will be
crtlerged by going downstream _ feet aztd startrrtg s new embanionent with 1.5:1 upstream and
downstream slopes. The new embenkmmt will tie into the existing embartlmtenl and use the upstream
slope to part oCthc upstream slope oCthe new embankment. Tnaxial shear and pore pressure tests will
be done on samples from the existing starter dike.
bj COM, Inc. cumnUy plans to rise matetial'tirpatream Bom the exuttng tarUrtga pond as borrow for die
new embanlattrnt. The borrow metetie! will be tested as pert of the design end specificationc that will
be prepared for the new embanlonrnt Qtialtty assurance testing wiU be included N the specifications
that will lx given to the division for approval prior to embenkmmt corutruchon.
cl Cross sections will De included az pan of the design specifications.
d) Design specifications for the ambattkment wdl include line installation rend queGry uaunnee
spectHcatrons. COM, tnc. Boas nor plan ro extend the User on the upstream dde or die new
embenkmeny bu[ will include liner installation in the borrow arcs m a point above the 5nd design fill