2010-10-22_GENERAL DOCUMENTS - M1999120

• Permit No: M1999120
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Date: 10/22/2010
• Doc Name: Complaint Letter
• From: DRMS
• To: Mr. Ross Bachofer
• Permit Index Doc Type: Gen. Correspondence
• Email Name: DAB
• Email Name: AJW
• Email Name: ECS
• Media Type: D
• Archive: No

_ STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
COLORADO
D I V I S I ON OF
RECLAMATION
MINING
SAFETY
MEMORANDUM Bill Ritter, Jr.
Governor
Mike King
Executive Director
To: David Berry, Director Office of Mined Land Reclamation Loretta Pineda
Director
From: Tim Cazier, Environmental Protection Specialist
Date: October 22, 2010
Re: L.G. Everist Fort Lupton Sand and Gravel Mine, Permit No. M-1999-120, Bachofer Property Flooding as a
Result of Reclamation Slurry Walls
Background
Mr. Ross Bachofer of La Salle, CO has provided anecdotal evidence to DRMS and others that the frequency with which
his property floods is increasing. Mr. Bachofer's property is located near the South Platte River, between the east bank of
the river and the Platteville Ditch. Mr. Bachofer contends the more frequent flooding is a result of slurry walls
constructed around several of the Everist Fort Lupton Mine Pits. He cites a recent USGS report titled "Land-Use Analysis
and Simulated Effects of Land-Use Change and Aggregate Mining on Groundwater Flow in the South Platte River Valley,
Brighton to Fort Lupton, Colorado" (Scientific Investigations Report 2010-5019) as evidence supporting his claim.
Report Summary Relative to Increased Frequency of Flooding
The purpose of the USGS report is to present the results of a land-use analysis and the results of model simulations (using
MODFLOW-2000) predicting the effects of land-use change and aggregate mining on the groundwater flow in the South
Platte River valley between the cities of Brighton and Fort Lupton, Colorado. It should be noted that the Everist Fort
Lupton Mine Pits are near (approximately '/2 mile) the downgradient boundary of the subject study area (Ref. Figure 1;
USGS 2010).
The following points addressed in the report support Mr. Bachofer's claim that the reclamation efforts (e.g., slurry walls)
at the Everist Fort Lupton Mine Pits may have contributed to higher water elevations in the South Platte:
1. The subject report notes in the introduction that "Pits lined with low-permeability material create barriers to
groundwater flow that can cause groundwater levels to rise upgradient from pits and decline downgradient from
pits." Results of MODFLOW simulations predict that the lined pits do cause mounding (on the order of 2 to 4
feet) upgradient of the existing Swingle South, Ft Lupton West and Ft Lupton East pits (Ref. Figure 34; USGS
2010). The existing pit immediately to the south of these (Arena Loch) is modeled as an unlined pit.
2. The report discusses the effect active pit dewatering has on groundwater levels. Pit dewatering does lower the
groundwater levels locally within the radius of influence. Specific distances for individual pits are not addressed
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