Granite Construction Revised Mining and Reclamation Plan
[Information up to date as of 08/08/17]
Upon completion of Staff’s review, the project will go before the Director of Planning and Development to consider conceptual approval of the following:
- Conceptually make the required findings for approval of the project specified in Attachment A of this staff report, including the California Environmental Quality Act (CEQA) findings.
- Conceptually certify the addendum to the Environmental Impact Report (03-EIR-10), included as Attachment C.
- Conceptually approve the project, Case Nos. 03CUP-00001-00024 and 03RPP-00001-00001 subject to the conditions included as Attachments D & E.
- Direct staff to refer the amended Reclamation Plan to the Division of Mine Reclamation (DMR) for review and approval and then return to the Director for final determination.
Mining operations at the site began in the 1920’s. The existing mining and processing facility has been owned and operated by Granite Construction Company (Granite) since the 1970’s. Current activities at the site include mining operations with concurrent reclamation, operation of a rock plant facility which processes extracted and imported aggregate, production of asphalt through the operation of a hot-mix asphalt (HMA) plant, production of rubberized asphalt and lime marination of asphalt aggregates. Materials produced at the site are used in public works and Caltrans projects throughout the County.
At current average extraction rates (275,000 tons per year between 2000 and 2010) known aggregate resources at the site would be exhausted in approximately 8 years. By decreasing onsite excavation and increasing the rate of aggregate imports from offsite mines, the applicant proposes to extend onsite mining operations by 48 years to 2064 while continuing to carry out the existing operations described above.
Final Subsequent Environmental Impact Report can be found here
Granite Construction Company (applicant) currently operates an aggregate mining and asphalt mixing facility permitted by the County of Santa Barbara (the County) under Conditional Use Permit (CUP) 03CUP-00000-00024 and Reclamation Plan (RPP) 03RPP-00000-00001. The proposed project includes a request for an amended CUP (03CUP-00001-00024) and amended RPP (03RPP-00001-00001) to increase the amount of aggregate imported to the site, reduce the annual on-site aggregate production estimate, and revise the timing of mining phases and reclamation end date. This proposal would extend the project through year 2064, an additional 48 years.
Based on existing permitted reserves, i.e. reserves above the water table, there is an estimated 2 million tons of aggregate material on the project site (see Table 3-1). Based on the historical average material extraction rate of about 275,000 tons per year (based on data from 2000 to 2010), the facility currently has approximately 8 years of reserves. This scenario does not include the import of virgin materials or the incorporation of recycled asphalt product (RAP) from construction and demolition recyclable material in the Hot Mix Asphalt (HMA).
3.1 Site Facilities and Equipment
The facility has three primary components: the mining and reclamation operation, the rock plant (which includes the recycled aggregate products noted above), and the HMA plant. Mining operations include the excavation of aggregate from the mining areas, the loading of mined materials, and the transport of material to the rock plant. Materials that are not economically feasible to sell (i.e., “sub-economic”) are returned to reclamation sites via a slurry pipeline that is moved as needed. Facility components are all essential to HMA production, but do not necessarily need to operate concurrently on a given work day. For example the HMA plant may be the only component operating on a given day, supplied from onsite stockpiled inventory.
Non-extraction activities are limited to the Phase V area, which is approximately 35 acres, and includes the rock plant (approximately 31 acres), HMA plant (approximately 2 acres), materials testing lab and portable office trailer (approximately 2 acres). A site plan showing Phase boundaries is included as Figure 2 of Attachment F. Product specifications require operational flexibility causing stockpile footprint locations and sizes to fluctuate and may require temporary equipment (such as lime marination or recycled rubber plants) to periodically be brought on site and placed in the 31 acre area of the rock plant.
The rock plant comprises the majority of the Phase V area and consists of various conveyors, hoppers, crushers, and stockpiles. At the rock plant, mined materials are sorted by size fraction and stored in various stockpiles for aggregate sales and primarily for use in the HMA plant. The rock plant uses water for washing and sorting material, and houses the pump for the sub-economic material return to the reclamation site via slurry pipeline. Product specifications often require lime marination of aggregate, recycling of concrete and asphalt materials, or other specialty HMA products (such as the incorporation of recycled crumb rubber). When required, these processes are conducted in the vicinity of the rock plant. Portable plants and equipment are brought on site on an as-needed basis for these processes and products.
The HMA plant is located on the west side of Phase V and mixes aggregate with asphalt oil binder to produce asphaltic concrete used in paving operations. The desired aggregate size fractions are set depending on the desired asphaltic concrete specifications. Asphalt oil is heated and then mixed with the aggregate, typically in a mix of about 7% asphalt oil and 93% aggregate. Aggregate of the desired size fractions and characteristics is sent via conveyors to the natural gas-fired drier and then to the pug mill for mixing. Haul trucks pull up to the plant, are loaded with HMA, and then deliver the product to its destination. The HMA plant only operates on demand as asphalt concrete is not stored on-site longer than 8 hours with current equipment.
Main rock plant components include the following:
Approximately 30 conveyors
2 Cone crushers
1 Jaw crusher
1 Sand screw
2 Coarse material washers
2 Control trailers (one stationary, one mobile)
2 Storage containers
Main HMA plant components include the following:
Stack (includes screen, pugmill, and hot bins)
2 Truck scales
2 silos (200 tons)
Blue smoke filter pack
2 Oil Tanks (30,000 liters each)
2 million BTU (MMBTU) oil heater
130 MMBTU burner
Existing fleet equipment at the facility includes the following:
1 Hydraulic excavator (Caterpillar 345 or equivalent)
2 Front end loaders (Caterpillar 988 or equivalent)
2 Haul trucks (Caterpillar R30 or equivalent)
1 Motor grader
1 Water truck
3.2 Existing and Proposed Operations
The proposed project would continue the following activities at the site:
Stockpiling of topsoil and reservation of these materials for reclamation purposes.
Mining of the site in defined phrases of less than 30 acres, which are identified on the mining plans.
Continue to limit mining and reclamation activities to a maximum of three concurrent active mine phases.
Backfilling of the mined area to a height of approximately 5-7 feet above the water table and reclamation of the mine area at a nominal depth of approximately 15 feet below original grade (in accordance with the approved Reclamation Plan)..
Retention of a 50-foot wide levee of native in-situ material along the south bank of the Santa Ynez River, and a 25-foot wide levee of native in-situ material along the east bank of Nojoqui Creek. Existing natural river banks along the Santa Ynez River and Nojoqui Creek would be left in place and not excavated or mined, and would remain after completion of proposed mining activities. These existing banks would appear as elevated levees relative to the reclaimed off-channel mining pits due to lower reclaimed land surface elevation; construction of levees would not occur.
Continue to process the mined aggregate at the existing rock plant.
Continue manufacturing asphalt concret at historical production rates.
Continue importing at least 15% limestone from the Bee Rock Quarry as an aggregate component mandated by the Santa Barbara County Air Pollution Control District.
Continue importing and processing construction/demolition recyclable material into recycled road base at historical production rates.
Continue producing rubberized asphalt and lime marinated aggregates for use in the HMA plant.
Increase importation of virgin aggregate, including limestone, as a supplement for mined material for use in the HMA plant or direct sale.
Decrease annual aggregate excavation and processing until the existing approved excavations are complete, then reclaim in compliance with the approved Reclamation Plan.
Extend facility life for an additional 48 years to 2064.
A. Import of Virgin Rock Materials The proposed project would allow import of up to 300,000 tons per peak year of aggregate materials (including limestone) for use in HMA production and for direct resale. The imported materials would originate from other permitted mines, such as Bee Rock Quarry located near Santa Ynez (CA Mine ID# 91-42-0006) or Sisquoc Mine located near Santa Maria (CA Mine ID# 91-42-0003). Granite Construction Company currently imports up to 57,000 tons per peak year of limestone aggregate from the Bee Rock Quarry, which is used in the HMA process as required by the facility’s air permit.
Native geologic materials at the project site have a high percentage of low-density silts and clays which could potentially preclude attainment of certain public works and Caltrans specifications for asphaltic concrete. Import of virgin aggregate materials from hard-rock limestone sources would improve asphalt density and achieve agency mandates for aggregate specifications.
B. Comparison of Peak and Annual Throughputs Table 3-2 presents a comparison of peak annual throughputs for the existing operations as well as what would be allowed under the proposed project. Data for the existing operations are based on historical records from 2000 to 2010.
Table 3-3 presents a comparison of average annual throughputs for existing operations as well as what would be allowed under the proposed project.
C. Life of Mine Estimates Table 3-4 illustrates the relationship between aggregate supply, either from on-site mining or import, and the life of the mine. The more aggregate that is imported from offsite, the less aggregate needs to be mined on-site and, therefore, the aggregate reserves would last longer and the life of the mine would be extended. The ratio of aggregate import versus on-site aggregate extraction is dependent upon the asphalt product specifications dictated by customers. Estimates in Table 3-4 are based on the amount of aggregate supply required to continue asphalt production and aggregate resale at historical rates.
Aggregate demand and consumption rates are driven by market demand. This is due to the nature of public works and infrastructure projects for which most of these materials are produced.
D. Reclamation and Site Drainage Under 03-CUP-00001-00024, the site would also continue operating under the approved Surface Mining and Reclamation Act of 1975 (SMARA) Reclamation Plan and Financial Assurances.
No substantial change is proposed in the currently approved Reclamation Plan, with the exception of the annual on-site aggregate production estimate, phased mining and reclamation end dates, and mine termination date. Table 3-5 presents the revised phased mining and reclamation end dates.
It is proposed that reclamation of the site would be to the same approved final elevations included in 03RPP-00000-00001 and the ultimate reclaimed land use would remain as irrigated row-crop agriculture. Mining of the Phase V area would be reserved for the final phase. Demolition and removal of the process plant and infrastructure would precede mining of Phase V. A temporary processing plant and associated infrastructure would be established on a portion of Phase VI during the mining of Phase V.
The mining area and final reclaimed surfaces drain toward the northwest corner of the Bazzi property (APN 137-270-015). The final Reclamation Plan calls for the installation of three 48-inch culverts that act as a drain in the northwest corner of the property (Phase IX levee) near the confluence of Nojoqui Creek and the Santa Ynez River. The river side of the culverts will be equipped with flap-gates to prevent backflow into the mine site from the river during high flow periods. The inlet and outfall surfaces of the levee and river bank have been engineered to include a concrete or rock apron and/or concrete sand bags to prevent erosion. Provisions for the culverts were previously permitted as part of the 2005 CUP.
In reclaimed areas, final site grading will result in a uniform reclamation surface, which extends from Phase I toward the northwest corner of Phase IX. This surface will have uniform grading to allow for surface water runoff to leave the site via the culverts described above. An exception to the uniformity of grading will be internal drain areas in the northwest corner of Phases VI, VII and VIII until the final reclaimed surface has been created with surface water flows directed toward the northwest corner of Phase IX.
Pursuant to the current permit, an additional drainage swale has been installed along the southern margin of Phases VI and VII to intercept storm water run-on flows from the hillside to the south of the Project area. This swale connects to a culvert draining directly to Nojoqui Creek at the southwest corner of Phase VII.
Mining of the project area will result in an in-situ levee along the south bank of the Santa Ynez River and on the east bank of Nojoqui Creek. The tops of these levees will remain undisturbed. The slopes from the top of the levee to the reclaimed mine surface will be graded to 2:1 (H:V) and will be planted with an approved erosion control grass mixture in accordance with the approved Reclamation Plan and SMARA requirements. Trees will also be planted along the levee in accordance with the Visual Screening Plan (see section (f) below).
E. Water Resources Water for dust control and crushed rock screening is provided by two on-site wells. Approximately 2,000 gallons of water per minute [1.2 million gallons per day (MGD)] is pumped for use in rock crushing and screening operations; the majority of this water, minus the amount lost during processing and to evaporation, is then returned to the mine pit in the form of a water-and-sand slurry that deposits the sub-economic mineral fractions in a “beach-like” deposition within the active reclamation area. After the inert backfill materials are deposited on the pit floor, the water portion of the slurry decants and then naturally infiltrates to groundwater. At times when ground water is exposed on the pit floor due to seasonal fluctuations in the ground water table, returned process water decants directly to the pit floor.
F. Visual Screening Plan The Visual Screening Plan would be implemented prior to Phase IX grading and excavation activities. The plan would provide visual screening of the project site from traffic on U.S. 101. Screening vegetation would be installed immediately east of the Nojoqui Creek bank on the western and northwestern margins of Phases VII and IX. A mixture of native deciduous and evergreen trees would be installed to visually buffer the mining area from the highway corridor. Proposed tree species shall include natives which would grow to heights in excess of 50 feet within a period of 15-20 years. This line of trees would be established with 5 to 15-gallon plants and provided with a dedicated PVC irrigation line from project water supplies. The irrigation system would be equipped with a timed automatic control system to regulate the watering schedule.
G. Additional Truck Trips and Changes in Product Import The Gardner Ranch Facility is served by an exit ramp from U.S. 101 and an easement on a private road across the Bazzi property. HMA is shipped primarily in 20-ton trucks while all other materials are shipped primarily in 25-ton trucks. A summary of the site’s historical haul truck traffic (based on data from 2000 to 2010) is presented in Tables 3-6 and 3-7.
The proposed project would increase the amount of aggregate imported to the site, which would offset the reduction in on-site aggregate production. The proposed increase in truck traffic is presented in Tables 3-8 and 3-9. The proposed project would not increase peak day or peak hour traffic at the facility; i.e., the peak historical day of haul truck trips would not be exceeded by the proposed project. Rather, near peak days would occur more often throughout the year. Furthermore, peak hour traffic is limited by equipment and facility specifications (asphalt load-out rate, loader loading rate, site haul truck routing) that would not change as part of the proposed project.