00016528 Material Source Narrative.pdf

Date: March 23, 2026

TO: Warren Nelson

ODOT Transportation Maintenance Manager Prineville/Mitchell/Madras

Ramon Alonso Maintenance Operations Liaison Region 4

FROM: Scott Billings, C.E.G.

Sr. Engineering Geologist

SUBJECT: Material Source Narrative

Prospective Material Source – Brooks Quarry ODOT Source # OR-35-014-4, DOGAMI # 35-0021 US26 (Ochoco Highway, #041), MP 59.48 District 10 (Mitchell) Sanding Rock Production 2026

Introduction This memo and attachments should be duplicated and distributed to all bidders that inquire about this prospective material source, as per Section 00120.25 of the Oregon Standard Specifications for Construction, 2024 ed. Any changes to the Plan or special provisions for the material source must receive approval of the Engineer.

The prospective material source is a developed quarry site known as Brooks Quarry, located in the NE¼ of Section 25, Township 11 South, Range 20 East, W.M., approximately 6.7 miles west of Mitchell, OR on the US26 (Ochoco Highway). Brooks Quarry is an ODOT-owned source and is accessible directly from the highway via two access roads located on the southeast side of the highway at MP 59.73 and MP 59.48. Wheeler County has approved a Conditional Use Permit and the source has a current DOGAMI permit (see attached). The 20.12 acre site has approximately 1.7 acres available for stockpiling and processing aggregate, which includes approximately 0.28 acres south of the cross-culvert drainage ditch at MP 59.65 that may be used for stockpiling.

The development of this source has been based on subsurface information obtained from blasting drill holes in and around the existing excavation area, where quality aggregate products have been produced in previous operations, including most recently in 2020-2021. The current proposed Plan is for approximately 10,000 cubic yards of produced sanding aggregate product for use as traction during winter driving conditions.

STATE OF OREGON DEPT OF TRANSPORTATION

Geotechnical Engineering / Engineering Geology / Hazmat Section Mountain Unit – Roseburg / Bend / La Grande

(541) 410-6693

Material Source Narrative Brooks Quarry ODOT GEEGH – Mountain Unit

Source Geology The source material in the Brooks Quarry is intrusive andesite rock (Tia) mapped as andesitic plugs, dikes or sills of the Clarno formation from the Eocene to Oligocene epochs (53 – 26 million years bp). The western portion of the site is mapped as the Ross Flat Member (Tcr) of the Clarno Formation and consists of terrestrial sedimentary rock of approximately the same age1 – however this second rock material type is not desirable for production. The andesite source material is described as dark gray to brown and green-gray, durable, and slightly to moderately weathered, and exhibits closely spaced, blocky entablature-type jointing. The undesired sedimentary rock is described as dull gray to light gray color and non-durable (friable), with largely unknown structure and a tendency to disintegrate into silt and sand-size particles when disturbed or exposed to the elements.

No subsurface investigation was performed for this project, and no rock core or aggregate material samples are available for inspection. However, surface samples and aggregate products have been collected and tested for previous projects, including most recently in 2019, 2020, and 2021. For more information, please refer to the Source Use History section below and attached laboratory testing results.

Current Project-Specific Development Plan Loose material from previous blasts has been consolidated in two separate piles, and may be used in the overall rock production. This quantity is not expected to be enough, so the development concept for the completion of this operation is to excavate the southern part of the quarry in an easterly direction, so that the future pit floor elevation matches the current elevation of the existing processing and stockpile area, as shown on plan sheets (GE01 and GE02). It shall not be excavated in a southerly direction to avoid material being shot into the creek. The finished backwall height will be approximately 45-50 vertical feet above the floor with a 4V:1H sloped face. It is important for the long-term development of the site that the excavation be constructed as shown in the Plans.

Much of the excavation area is already stripped of overburden, therefore only minimal overburden removal is anticipated for the operation. Drilling, blasting, and excavation activities should avoid disturbing the soft, friable sedimentary rock adjacent to the northwest edge of the excavation area.

As stated in the Special Provisions Section 00235.45, a maximum of 250 cubic yards of oversize with a maximum dimension of 2.5 feet may be stockpiled in the material source; no other loose material exceeding 1 foot diameter may be left on the site. Given these requirements, special consideration should be taken in preparation of the bid to take into account the possible need to handle or reduce oversize material to a usable size. Even if the bidder assumes that the blasting required for this contract is successful in reducing the quantity of oversize, special equipment or methods may still be necessary for secondary size reduction.

Contractors should bid accordingly to handle and reduce oversize material.

1 Oregon Department of Geology and Mineral Industries, GIS Geologic Data Compilation.

Material Source Narrative Brooks Quarry ODOT GEEGH – Mountain Unit

The proposed plan provides for the removal of rock products required for the D10 Sanding Rock Production project, while also ensuring that the site is left in a condition that will facilitate systematic development in the future. Special care will need to be taken to avoid encroachment of operations and intentional or inadvertent transport of soil, sediments, aggregate or rock fragments of any size into the drainage ditch that flows through the middle of the site or into the riparian area along West Branch Bridge Creek. No encroachment or impacts to this area are allowed. As part of the Erosion and Sediment Control Plan, the stormwater control berms shall be improved/constructed before work begins, and maintained throughout the operation. When the current operation is completed, the site must be left in a stable and safe condition.

Source Use History The prospective material source has been used for numerous highway construction and paving projects in the past. Over the past 10 years alone, the material source has been used for shoulder aggregate production in 2015 and 2017, stone embankment and riprap for the OR207 Slide Repair project in 2019, approximately 10,000 cubic yards of sanding aggregate and 7,000 cubic yards of chip rock were produced for maintenance applications in 2020, and most recently in 2021 for stone embankment for a nearby bridge replacement.

Attached in this narrative are 2019, 2020, and 2021 laboratory testing reports for riprap (Lab Report No. 19-002474 and 21-001300) and chip seal aggregate (Lab Report No. 20-001207) (respectively) from when the prospective material source was used. Additional laboratory testing reports dating back to 1952 are available on request.

General Information Contractors should make an on-site visit to this prospective material source to familiarize themselves with the existing conditions and appearance of the site in advance of preparing their bids. As per Section 00120 - Bidding Requirements and Procedures of the Oregon Standard Specifications for Construction, 2024 ed., Contractors shall carefully examine the available information for the prospective material source. Based on the on-site visits and review of all available information, the Contractor will then be able to prepare a bid based on the existing site conditions, the conditions they expect to encounter at the time of the proposed operation, and on the most accurate information available for the source.

Documentation contained within this Narrative Packet for the Prospective Material Source is for informational purposes only; they are not intended to replace those pages supplied in the Bid Packet.

Additional Information Any contractor interested in viewing documents or information not summarized or provided herein should contact the Project Manager’s office to review the material. A geology staff representative must be included when information is being reviewed to ensure that content is disseminated accurately, fairly, and consistently throughout the bid process.

Attachments DOGAMI Operating Permit Laboratory Report Nos. 19-002474, 20-001207, 21-001300