Consideration and Approval of Job Order Contract thru Mohave Educational Services Contract: Cinder Lake Landfill, Cell D-Rock Coring Project
 

1. Approve the contract with Mohave Educational Services, through the Job Order Contract (JOC) project delivery method for site work with SDB Contracting Services, Inc. (ROC #070507) under the scope of work (attached), in the amount of $62,932.83, with a contract time of 60 days: and
2. Authorize the City Manager to execute the necesary documents.

Obtaining cores of rock and soil from the South Borrow Pit (Cell D) will allow staff to determine strategies for future development of the site in an effort to extend the life of the landfill to the maximum number of years possible with the ultimate goal of saving money in delaying the development of a new landfill. 

$115,000 is budgeted for this project in FY13 in account 280-4104-790-4103 (Project Number 410404).

Maintain and deliver quality, reliable infrastructure-
This project will allow staff to determine whether it is feasible to increase the amount of available airspace at the landfill, thereby extending the closure date. In addition, valuable soil resources could be confirmed for future cells.

No

Option A-Approve the contract with Mohave Educational Services through the job order contract project delivery system with SDB Contracting Services, Inc. under the existing scope of work

Option B-Reduce the scope of work

Option C-No Action until the project is further warranted

The Cinder Lake Landfill Solid Waste Facility Plan acts as the guiding construction document and prescribes excavation depths within the future expansion area known as Cell D as shown in Figure 1 (33 Acres).  The depths established by the engineer of record were based on marginally rippable (extractable) rock as determined by drillers’ logs and geophysical surveys. It was assumed that in the future, the City’s only desirable method of excavation was through ripping the soil and rock with bulldozers and excavators.
  
In the summer of 2011 sonic drilling methods were performed within the vicinity of the landfill. The mission of the project was to determine the depth of cinders within the Cinder Lake Basin. One bore hole (CL 7) located within the vicinity of Cell D extended 16 feet into the underlying basalt unit. Upon examination of the extracted soil and rock, staff ascertained that the crushable rock within the basalt unit may serve as a viable source of aggregate for future City infrastructure. Staff compared the previous geotechnical report with the new samples and determined that drilling and sampling of rock cores within the basalt unit was justified.

Cinder Lake Landfill currently has an adequate volume of on-site soil to suit immediate needs for daily cover of trash. However staff continues to seek readily available resources of alternative cover in order to decrease the inevitable soil deficiency.

Cell D has been excavated to the furthest extent possible with existing landfill equipment.  Staff has compared the existing topography with the final design depth and calculated approximately 650,000 cubic yards of soil and rock remain within the 33 acres. Some portions of the site have as much as 15 feet of soil and rock that lie between existing grade and the design elevation. Other heavy equipment (excavators) could be used to perform the future excavation activities. However staff has counseled with a number of engineers and contractors who concluded that the volume of available rock within the 33 acre site warrants drilling and blasting prior to excavation.

Prior to drilling and blasting it is necessary to gain a comprehensive understanding of the geology by means of extraction (coring), sampling, and testing of soil within the site. Extraction of solid cores of rock will allow the staff to determine whether a more optimal depth can be achieved within the site boundaries. In addition, drilling and sampling in Cell D will give staff a more accurate definition of soil characteristics that exist within the boundaries. The analysis of the soil and rock will allow staff to establish essential benchmarks, calculate the approximate volume of remaining rock, calculate costs for processing rock, and assess the marketability of the rock.

Based on existing soil usage, the landfill will inevitably have to import soil (2.5 to 3.5 million cubic yards) from other sources in the region. The most readily available imported soil comes from the Cemex Grey Mountain facility located north of Flagstaff. The material consists of gravel-sized particles, and is approximately $18 per ton (includes delivery). The larger particle size makes the material less desirable due to its high porosity. Therefore approval of cover material with particle sizes typical of gravel would have to be granted by the Arizona Department of Environmental Quality prior to implementation. The typical industry standard for daily cover consists of soil particle sizes equivalent to sand. The most reliable source of imported sand is from the Verde Valley at a present day rate of approximately $30/ton (includes delivery).

The rock coring project is being considered to determine whether the benefits to the commmunity could be realized.

None

Option A-Approve the contract with Mohave Educational Services through the job order contract project delivery system with SDB Contracting Services, Inc. under the existing scope of work

Option B-Reduce the scope of work

Option C-No Action until the project is further warranted

09/04/2012 EAB