2015-12-07_PERMIT FILE - M2014071

• Permit No: M2014071
• IBM Index Class Name: PERMIT FILE
• Doc Date: 12/7/2015
• Doc Name: Need for Mined Land Reclamation Board Permit
• From: Denver Water
• To: DRMS
• Email Name: MAC
• Media Type: D
• Archive: No

Michael Cunningham
November 24, 2015
Page 2
from the U.S. Army Corps of Engineering's. As part of the permit process an EIS was developed for the
project, which specifically includes impacts from an onsite quarry.
The existing Gross Dam is a 340 foot tall concrete gravity dam located on South Boulder Creek in Boulder
County, Colorado. The Gross Reservoir Expansion project proposes to raise Gross Dam by 131 feet to a
final height of 471 feet. A downstream roller compacted concrete (RCC) buttress raise matching the
existing curvature of the dam is planned. The raise will require about 860,000 cubic yards of concrete,
and the aggregate for the concrete (about 1,500,000 tons) is expected to be borrowed from an onsite
quarry. The alternative quarry is located about 1 mile south of the dam and is comprised of South
Boulder Creek Granite, a fine to medium grained granite which is particularly hard and resistant to
erosion. The borrow quarry and the dam are both located on Denver Water property within the FERC
Project Boundary. All material removed from the quarry will be used onsite and within the FERC Project
Boundary for the sole purpose of constructing the dam raise. Material will not be exported from the
site. When the project is complete the quarry will be submerged by the new reservoir.
Answers to "Is It Mining" Form
1. Legal Description — Gross Dam Raise Borrow Quarry: Section 19; Township 1S, Range 71; Boulder
County; Located about 5 miles east of Pinecliff, Colorado.
2. The extraction area is located on Denver Water property within the new reservoir footprint and
will be inundated by the expanded reservoir. Extracted material will be used to make concrete
for the dam raise. The dam is located on Denver Water property and within the FERC Project
Bounda
ry.
3. The operations will primarily extract granodirite and quartz monzonite material from rock
outcroppings and/or excavated areas.
4. The material will be extracted with common drilling and blasting techniques supported by
typical construction equipment such as drilling rigs, excavators, front end loaders, and haul
trucks.
5. Extracted material will be processed into aggregate, batched into concrete and only used onsite
for the dam raise construction approximately 1 of a mile from the extraction site. The
extraction site is located on Denver Water property and within the new reservoir inundation
area.
6. The extracted material will be processed onsite into concrete aggregate and batched into
concrete which will be used for the dam raise construction.
7. The material will remain onsite and within the FERC Project Boundary.
8. The proposed extraction area is approximately 15 acres.
9. The extraction excavation could reach depths of up to 180 feet.
10. The dam raise requires approximately 860,000 cubic yards of concrete. Denver Water
anticipates extracting up to 1,700,000 cubic yards (including overburden waste) to create the
required quantity of aggregate.
11. The material extraction will require the use of explosives.