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TO: Mayor Thomas J. Weisner
FROM: David E. Schumacher, P.E.; Superintendent of Water Production
DATE: February 16, 2016
SUBJECT:
Resolution to authorize a Professional Services Agreement for mine repurposing consulting services for the Lime Residual Underground Injection Control project for the Water Production Division.
PURPOSE:
To obtain City Council approval to attain a professional engineering services agreement with CNA Consulting Engineers, Minneapolis, MN (CNA) for mine repurposing consulting services for the Lime Residual Underground Injection Control project for the Water Production Division.
BACKGROUND:
All residents of the City of Aurora are provided with potable water from the city owned and operated Water Treatment Plant (WTP). The main treatment process utilized at the WTP is the lime-softening process. This process not only removes and collects the solid particles that are present in the raw water sources (Fox River, shallow well, and deep well water), but also softens the water to provide customers with more aesthetically pleasing drinking water. As the solid particles are removed by the treatment process, they are concentrated and collected and this by-product must be ultimately disposed.
Since the WTP's construction in 1992, the lime residual has been disposed by landfilling at great annual expense to the city. In 2012, through an IEPA permit, the WPD began a program to dispose of the lime residual via land application on agricultural fields. Land application allows a beneficial reuse of the waste product and reduces the cost of ultimate disposal by approximately 25%. As this process is still expensive, starting in 2006, a more efficient method of ultimate disposal was investigated regarding placing the lime residual in repurposed portions of a limestone mine.
DISCUSSION:
The LaFarge-Conco Limestone Mine (LC-Mine) is located at the intersection of Interstate 88 and IL Highway 25. The mine is approximately 200 to 400 feet below grade, is located in both Aurora and North Aurora, and is mainly used to produce limestone and dolomite aggregates for construction uses. The portion of the mine located in Aurora is typically referred to as the south mine and currently has two distinct levels with a third level to be constructed in the future. The first two levels of the mine are almost spent (completely excavated) and thus are no longer useful for material production.
As such, the city and LaFarge have been in discussions for quite some time to develop a plan to allow the lime residual material to be placed into the first two levels of the south mine as a method of ultimate disposal. In order to proceed with the placement of the material, a permit from the Illinois Environmental Protection Agency is required. Through a lengthy process and via Permit No. UIC-015-COA, the Illinois Environmental Protection Agency has approved the underground injection of the lime residual into the spent portions of the L-C Mine as a method of ultimate disposal. This permit became effective on August 24, 2015.
The city wishes to have team members who have significant experience with repurposing underground mine spaces for various uses such as transportation facilities, underground science laboratories, and occupied underground spaces. This experience would be used to review the geostructural and groundwater aspects, "in-mine" designs and constructions, and any other facets of the overall project dealing with construction and long-term use of mine spaces and facilities. As such, a proposal was received from CNA for mine repurposing consulting and review services for all "in-mine" phases of the overall project. CNA would also be available to perform occasional on-site inspections during the actual construction progress on an as-needed basis.
Funding for the professional services and a portion of the construction of this project has been requested in the 2016 City Budget as CIP #I044. The remainder of the funding for the actual construction of the improvements, which are currently scheduled to begin in early 2017, have been requested in the 2017 Budget also as part of CIP #I044.
IMPACT STATEMENT:
Based on information provided by a different consultant, the city will save approximately $1,100,000 annually by changing the ultimate disposal of the by-product material from land application and land filling to underground injection in the repurposed sections of the L-C Mine.
RECOMMENDATIONS:
That the Mayor and City Council approve the attached resolution authorizing the Purchasing Director to execute an agreement with CNA Consulting Engineers for general mine consulting services for the Lime Residual Underground Injection Control project on a time-and-material basis, for a not-to-exceed amount, of $190,000.00 for the Water Production Division. It is further recommended that this matter be forwarded to the joint meeting of the Buildings, Grounds, and Infrastructure and Finance Committee’s for review and recommendation.
cc: Alderman Garza, Chairman
Alderman Mesiacos
Alderman Johnson
Alderman Bohman, Alternate
Alderman O’Connor, Chairman
Alderman Mervine
Alderman Bohman
Alderman Mesiacos, Alternate
CITY OF AURORA, ILLINOIS
RESOLUTION NO. _________
DATE OF PASSAGE ________________
title
A Resolution to Authorize a Professional Services Agreement for mine repurposing consulting services for the Lime Residual Underground Injection Control project for the Water Production Division
body
WHEREAS, the City of Aurora has a population of more than 25,000 persons and is, therefore, a home rule unit under subsection (a) of Section 6 of Article VII of the Illinois Constitution of 1970; and
WHEREAS, subject to said Section, a home rule unit may exercise any power and perform any function pertaining to its government and affairs for the protection of the public health, safety, morals, and welfare; and
WHEREAS, the Aurora Water Treatment Plant produces a lime by-product from the lime softening process which must be ultimately disposed; and
WHEREAS, underground injection of the material into a repurposed limestone mine is expected to be less costly over the life of the space available compared to the current disposal practice of land application and landfilling; and
WHEREAS, a permit has been received from the Illinois Environmental Protection Agency to allow the by-product material to be placed into select areas of the mine; and
WHEREAS, a proposal has been received from CNA Consulting Engineers to provide professional engineering services for mine repurposing consulting services for the project; and
Whereas, budgetary authority is granted and funds are available in the 2016 City Budget account No. 510-4058-511-73-07;
NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Aurora, Illinois, as follows: The Purchasing Director is hereby authorized to execute a professional engineering services agreement with CNA Consulting Engineers for mine repurposing consulting services on a time-and-material basis, for an amount not-to-exceed $190,000.00 for the Lime Residual Underground Injection Control project.
PASSED AND APPROVED on ______________.
AYES ____ NAYS ____ NOT VOTING ____ ABSENT ____
____________________________ __________________________
Alderman Bohman, Ward 1 Alderman Garza, Ward 2
____________________________ __________________________
Alderman Mesiacos, Ward 3 Alderman Donnell, Ward 4
____________________________ __________________________
Alderman Peters, Ward 5 Alderman Saville, Ward 6
____________________________ __________________________
Alderman Hart-Burns, Ward 7 Alderman Mervine, Ward 8
____________________________ __________________________
Alderman Bugg, Ward 9 Alderman Johnson, Ward 10
____________________________ __________________________
Alderman Irvin, At Large Alderman O’Connor, At Large
ATTEST:
____________________________ __________________________
City Clerk Mayor