Project Overview

Martin Marietta is evaluating potential aggregates sales yard and asphalt/ready-mix concrete production sites along railroads in Weld County that meet specific transportation and production criteria. One of the locations under consideration is the “Highway 34” site, located at 27486 Weld County Road 13, one-half mile south of Highway 34 in Weld County. The proposed site is made up of two parcels, totaling 133 acres. The western parcel is currently developed and permitted in Weld County to allow for the operation of a construction business. The eastern parcel is currently agricultural farmland.

Martin Marietta submitted a Use by Special Review (USR) application for the Highway 34 Development in April.  We developed a site plan that addresses the concerns of our neighbors.

Community members who participated in the neighborhood meeting in January 2015 will notice that the site plan presented in the neighborhood meeting is different that the site plan submitted to the County in the USR application.  After the public involvement meetings, various studies were conducted to evaluate potential impacts to surrounding properties and land uses.  These reports are included in the USR application and cover the topics of noise, traffic, health, air emissions, visibility, wildlife, water supply, and engineering review of existing irrigation ditches.

Findings in these studies led us to incorporate mitigation techniques into the USR site plan submitted to the County.

>> View Submitted Weld County USR Application.

Some of these mitigation techniques include:

  • Constructing earthen berms within the Highway 34 Development site, to address noise and visual concerns,
  • Operational sound controls in the asphalt plant activities,
  • Changes in the tank installation at the asphalt plant to address odor concerns,
  • White noise back up alarms for noise mitigation, and
  • Installing primary and secondary access is off Weld County Rd 13 to address employee safety.

Please review the USR application for the full inventory of mitigation strategies and to review the supplemental reports.

>> View Submitted Weld County USR Application

>> LINK to Project Visual Analysis Model (3D images)


Operations Overview

Highway 34 Operations is proposed to have three main components: a rail unloading facility to bring in raw material, an aggregate sales yard and an asphalt plant and a ready mix concrete plant. The rail loop will branch off the existing Union Pacific Railroad line to allow for the loading and unloading of aggregates required for sustaining economic growth in northern Colorado. Trains will deliver aggregate from Wyoming approximately two to three times per week.

Customers within northern Colorado will receive their materials from this site by truck. Generally, operations are planned to take place during daylight hours, six days a week. However, hours of operation are dictated by our customer’s project requirements, so at times, activities may need to occur early in the morning or at night. Therefore, we are asking the County for permission to operate 24/7 when needed.


Martin Marietta

Martin Marietta, an American-based company and a member of the S&P 500 Index, is a leading supplier of aggregates and heavy building materials, with operations spanning 32 states, Canada and the Caribbean. Dedicated teams at Martin Marietta supply the resources for the roads, sidewalks and foundations on which we live.

Although, Martin Marietta’s Rocky Mountain Division began in 2011, for the past 50 years, our personnel and operations have been a vital part of the northern Colorado community. We produce aggregate, ready mix concrete, asphalt and provide road construction services to the communities we help build and support.


Economic Benefit

Martin Marietta will invest an estimated $20 million in developing Highway 34 Development, employing over 100 people with an average salary and benefits of more than $70,000. Indirectly, the project will employ an estimated 4,300 employees who live and work in the region. Estimated property tax and sales tax generated by the project during the first 10 years is in excess of $36 million. Key customers that Martin Marietta serves in Weld and Larimer Counties include county and city governments, the Colorado Department of Transportation, general contractors, homebuilders, and oil and gas companies.

As aggregate deposits become depleted in Northern Colorado, construction costs and traffic congestion will increase as materials are imported from surrounding areas. Martin Marietta’s Highway 34 Operations will help reduce long-term construction costs and truck traffic by bringing in raw materials by rail to a central distribution point.

If one considers, an average home requires 400 tons of aggregates to build, with transportation being the largest cost associated with the materials, importing aggregates by truck cost 25 percent more than rail resulting in substantially higher costs to build a home. Increased construction costs also impact the costs to build schools, stores, streets and highways considering one lane mile of interstate requires 40,000 tons of aggregates.

Colorado consumed 48 million tons of aggregates in 2013. The aggregate industry in Colorado directly employs more than 1,600 people and indirectly employs 70,000 people (Source: Colorado Stone Sand & Gravel Association). Nationally, for every dollar spent in the industry generates $1.58 in the economy.

Community Support

Martin Marietta employees live and work in the communities in which we operate. Our success through the years is a direct result of being a good neighbor and involvement in the community. Educating future generations is important to Martin Marietta. Our team members provide educational tours of our operations to students from grade school through college level as learning opportunities related to science, math, geology and other environmental sciences.

We also extend these learning opportunities to the community and our neighbors, hosting regular meetings and open houses. Additionally we support and participate in local community activities such as support of youth sporting activities, the Greeley Stampede, Boy Scouts, food banks, local community events and many other organizations.

Martin Marietta has been a part of the community for more than 50 years. Our business is a long-term business and we are committed to supporting the communities we help build.


Aggregates (sand, gravel and crushed stone) are the building blocks for schools, homes, streets and highways and are foundational to every community.


Traditionally, aggregates in northern Colorado have been mined along the region’s rivers and streams. Materials are excavated by wheel loaders or excavators and transported to process plants that typically contain several crushers, conveyors and screens. If required, the material excavated from the ground is sized and crushed into different products.





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The finished products are loaded into trucks and transported to projects within the market. Transportation costs are a significant cost in the use of aggregate products. Due to this increased cost, companies host ready-mix and asphalt plants at the mine site; which in turn reduces the cost of these construction materials. In northern Colorado, the sources are becoming finer as mining operations move further away from the mountains. This means that in the near future, coarse aggregate materials will be imported into the region from places such as Martin Marietta’s Granite Canyon Quarry in Wyoming to support the economy and construction or rehabilitation of homes, schools, shops, streets and highways.

The raw materials are imported by truck or train. Truck transportation adds additional truck traffic to the regions streets and highways increasing congestion and maintenance costs. Trains are an alternative option to trucks when importing material into the region (one train replaces more than 400 trucks) and provide additional benefits to the region as trains are more environmentally friendly (rail releases three times fewer emissions than trucks) and more efficient (rail is four times more fuel-efficient than trucking).

Martin Marietta’s Highway 34 Operations will import aggregates using rail, estimated two to three trains per week in the future. Though trains may arrive at the site at any time of day, unloading activities will take place only during daylight hours. When the train arrives, it will be unloaded by a top unloading method or a bottom unloading. Top unloading involves parking the train on the loop track on the property and an excavator moving along the train removing aggregates from the railcar and placing in stockpiling trucks. Bottom unloading is conducted by moving the train around the loop, emptying each rail car into a hopper and conveying the material into a stockpile. It is anticipated that top unloading will occur at the site during the first couple of years and then transition to bottom unloading for the long-term.

Additional Information regarding aggregates:

Ready Mix



Concrete is a mixture of paste and aggregates (sand and rock). The paste, composed of cement and water, coats the surface of the fine (sand) and coarse aggregates (rocks), binding them together into a rock-like mass known as concrete. Cement is an ingredient in concrete and will not be manufactured at this site. Concrete is plastic and can be molded or formed into any shape when newly mixed, but is strong and durable when hardened. These qualities explain why one material, concrete, can build skyscrapers, bridges, sidewalks, and superhighways, houses and dams.

Besides cement, concrete may contain other materials including fly ash, a waste byproduct from coal burning electric power plants, similar to the volcanic ashes the Romans mixed with lime to obtain their cement binder. The concrete industry uses this material, which would normally have to be disposed in landfill sites.

Material is transported from our plant by truck to projects throughout Northern Colorado. The mixer trucks then return to the plants sometimes with concrete not utilized by the contractor. This material is then dumped into a recycling area and allowed to dry. Once dry, the material is moved to a storage pile and recycled into base or other aggregate products.

Watch this video to understand the full production process and to see what a ready-mix plant looks and sound likes during operation.

Additional Information regarding ready-mix concrete:




Making asphalt uses a process similar to baking a cake.ou measure all the right ingredients, mix them up and heat them for the final product. Asphalt starts with a mixture of sand, small and large rocks (called aggregate). Next, asphalt is heated and combined with the rocks — thus the name hot mix asphalt (HMA). The HMA must be kept pliable for proper installation

A typical Drum Asphalt plant makes asphalt continuously and can store asphalt for several days in a heated storage silo consisting of the following components:

Cold feed bins — Accurately meter the different aggregates used in the mix to the drying drum. Aggregates are usually stored in stockpiles or they may be stored in large silos or bunkers.

Asphalt cement storage — Asphalt cement is stored in tanks that meet stringent regulatory guidelines for spill prevention.

Dryer drum — Dries and heats aggregates by tumbling them through hot air.

Emission control system — Sometimes called a baghouse, this system operates similar to a vacuum cleaner by trapping and removing fine sand and dust particles and returning them to the mix.

Storage silos — Drum mix plants must have silos since they produce asphalt continuously. Storage silos are insulated and may be heated to prevent heat loss. A mix may be stored in a silo for days.

Watch the video to understand the full production process and to see what an asphalt plant looks and sound likes during operation.

Stored asphalt from the heated silos is loaded into trucks for delivery throughout the region for projects such as streets, highways, driveways and parking lots.

Additional Information regarding asphalt:
>> Coalition for SAFE – Safe Asphalt for Everyone


One of the primary reasons Martin Marietta selected this location was because the site has access to an active rail line and access to major arterial roads, which are not adjacent to access points into established neighborhoods.

Trucks and vehicles will enter and exit the site via County Road 13, with the majority of the vehicles traveling north to Highway 34.  A traffic study was required by Weld County as a part of the USR application.  The traffic study identified the amount of traffic projected to be generated as a result of the proposed project.  Martin Marietta will work with Weld County and the Colorado Department of Transportation (CDOT) to provide any required road improvements, as a result of the additional traffic from the proposed development.

It is important to note Weld County and CDOT’s long-term plans for Weld County Road 13 and Highway 34.   According to Weld County Transportation Plans, County Road 13 will be an extension of Colorado Boulevard, a major thoroughfare.  Also, the long-term plans for the intersection of Weld County Road 13 and Highway 34 is to have a grade separated intersection to accommodate the projected traffic.

Please refer to the USR Application for more details about the Traffic Study and Mitigation.

>> CDOT long-term plan for Hwy 34
>> Colorado Boulevard plan

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