We are driven by a desire to serve our communities with geotechnical and geological experience, and create smart, buildable design solutions.

Our Story

Although they didn’t know it, the Lithos Engineering team began to assemble well before the company was created. In 2007 Nate and Benny worked for a Denver-based Geotechnical and Trenchless firm where they learned to provide excellent engineering support on subsurface projects and establish professional relationships with the local engineering firms, owner organizations, and construction companies. In 2010 the local firm was acquired by a national-focused firm, introducing Nate and Benny to Robin who all became partners in the acquiring firm. In 2010 Robin first met Lance and was fortunate to be able to hire him in 2012.

Out of a desire for more sense of community, the four geotechnical and geological engineering professionals started Lithos Engineering to serve their local communities by providing clients and projects with recognizable value through prudent site evaluations, constructible solutions, and an understanding of project risks. Lithos focuses on tunnel, trenchless, geotechnical, and geological engineering and design services through innovative, collaborative, client focused consulting uniquely tailored to suit the needs of our clients and their projects.

lithos is hiring!

Entry level to Project Manager, Tunnel and Geotechnical Engineers.

Minimum Requirements:

  • Strong attention to detail with excellent analytical, judgment and problem-solving capabilities

  • Excellent written and verbal communication skills

  • Strong computer skills including proficiency in all MS Office software, AutoCAD, and various
    engineering software

  • Work well within an established and growing team environment.

  • Have reliable transportation to access job sites and a valid driver’s license in good standing

  • Willingness to travel to project sites and meetings when required.


We’re an experienced, energetic team that works hard in this beautiful place
we call home.


Robin Dornfest, PG, CPG


Robin specializes in engineering geology and geotechnical engineering as they relate to water and wastewater, oil and gas, transportation, aggregate producers, mining, and water supply and irrigation. Typically, his projects involve geotechnical/geologic investigations, pipeline alignments and crossings, geologic hazard evaluation and mitigation design, small dam design, permanent and temporary earth retention systems, groundwater control, oil and gas pipelines and facilities, highways and bridge construction, commercial and industrial developments, and land development projects. He has technical expertise in engineering geology, geotechnical engineering, slope stability, expansive soils, ground modification, earth retention systems, landslide and rock fall evaluation and mitigation, embankment dam design, groundwater control systems including slurry walls and dewatering well systems, and tunneling and trenchless projects. In addition, Robin has served as an expert witness and provided testimony, evaluated differing site condition claims, and regularly provides value engineering services to numerous client and project types.


Nate Soule, PE, PG, PMP

Vice President

Nate has experience in a variety of tunneling, geotechnical, and geological engineering projects. His focus is primarily on tunneling and trenchless engineering and is also constantly involved with more traditional geotechnical projects. Tunneling and trenchless engineering experience includes project management, tunnel design, feasibility analysis, geologic exploration, and contract document preparation. He also assists in plan and specification reviews and litigation support for projects across the country involving both tunnels and other types of construction. Other interests and areas of experience include cementatious grouting and support for hard-rock aggregate quarries.


Benny Siljenberg, PE, MBA

Vice President

Benny’s experience is in a variety of geotechnical, tunneling engineering and construction projects where he has provided benefit to projects for the owners’, contractor’s and prime engineer’s team. His diverse experience allows him to understand a project from all points of view and provide value to each project by considering how individual aspects will affect the overall project. Early in his career his primary focus on design and construction experience with civil structures such as pipelines, water and wastewater treatment plants and reservoirs that is beneficial as he focuses on developing teams, business and pursuits related to the these features.




Lance is a cofounder and associate of Lithos Engineering.  He has worked on and managed a variety of geotechnical engineering projects and has specific expertise in tunnel and trenchless construction. He has over 5 years of experience analyzing feasibility, designing, and observing and managing construction for tunnel and trenchless projects in Colorado.


Ryan Marsters, PE, PG


Ryan has experience conducting geotechnical and geologic evaluations for slope stability, geological hazards, abandoned mine subsidence, storm water, environmental compliance, ground water, shallow and deep foundations, roadways, tunnels, dams, pipelines and other civil works.

Ryan’s experience in tunneling, and underground construction includes trenchless design for transportation, water, storm sewer, and sanitary sewer applications. Specific tasks include preparation of Contract Documents, Geotechnical Baseline and Data Report preparation, litigation support and analysis, trenchless feasibility and constructability, tunnel condition assessment, field engineering, and historic tunnel evaluation and rehabilitation. He has served in a variety of roles on tunnel projects throughout the United States involving soft and hard ground and excavation using guided auger bore, guided pipe ram, TBM, MTBM, SEM, hand mining, and drill and blast methods. 



Project Manager

Matthew Olson is a professional engineer with experience in trenchless construction inspection and management, feasibility studies, preparation and review of contract documents, geotechnical investigations, and cost estimates for trenchless technologies including pilot tube, open shield pipe jacking, pipe ramming, microtunneling, horizontal directional drilling, pipe bursting, CIPP, and auger boring. While attending ASU, he prepared a thesis comparing existing jacking force predictive models to jacking force data he collected while working as a construction laborer on a pilot tube job consisting of over 1,600 lineal feet of gravity pipeline installation. In addition to his academic research experience, Mr. Olson worked as a laborer for Globe Contractors, Inc. during summers for seven years. He has valuable experience working from a consultant and contractor’s perspective regarding installation techniques that maximize workflow efficiencies and minimize project risk for trenchless operations.


Amara Meier, EI

Staff Engineer

Amara has experience as a Geotechnical Engineer focusing in the areas of tunnels, geological engineering, and environmental remediation. She has worked on a variety of geological and geotechnical engineering projects including pipelines, tunnels, geologic hazard assessments, permitting for pipeline inspections, Phase 1 Environmental Site Assessments, bathymetric surveys, oversight of emergency on-site water treatment through carbon filtration, subsurface explorations, analysis of geotechnical data, and the composition of geotechnical engineering reports. Long-term laboratory research programs include the compatibility and longevity of low-permeability engineered liners. She has conducted construction oversight and geotechnical evaluations of rock tunnels, a storm sewer re-alignment, municipal water tank stability risks, persistent sinkholes, pipe rehabilitation, a pond liner system, and debris-flow mitigation alternatives. Amara has also co-authored five peer-reviewed geotechnical conference and journal papers pertaining to her laboratory research and field work. 


Dylan Fawaz, EI

Staff Engineer

Dylan is a staff engineer for Lithos Engineering and graduate of Clemson University.  Throughout his career at Lithos Engineering he has become well equipped with experience and technical knowledge that has proven to be valuable on several projects. He has experience in many areas of geological and geotechnical engineering projects including water and wastewater treatment plants, pipelines, tunnels, rockfall mitigation, geotechnical forensic investigation, subsurface investigation, retaining structures, and the production of geotechnical data and engineering reports as well as calculation packages. He is currently pursuing his Master’s Degree in Geotechnical Engineering at Colorado State University.



Staff Engineer

Anna obtained a BS in Geological Engineering from the Colorado School of Mines in 2017 and prior to joining Lithos worked as a project engineer for a national environmental, geotechnical and civil firm. Anna has experience in geotechnical construction and environmental project engineering, as well as geotechnical analysis of coal ash impoundments, environmental remediation of industrial sludge, construction quality control management, development of geotechnical laboratory procedures, constructability analyses, and environmental compliance. Anna also has research experience in rock mechanics, emphasizing in-situ rock strength determination. With Lithos, Anna has gained experience in many areas of geological and geotechnical engineering projects, including coal mine subsidence analyses, subsurface investigations, construction oversight, tunneling, and the production of geotechnical data and engineering reports. Anna is an avid rock climber, slackliner, and skier.


troy duron, EI

Staff Engineer

Troy graduated with a Bachelor’s and a Master’s Degree in Geological Engineering from Colorado School of Mines. Troy’s undergraduate curriculum included a minor in Underground Construction & Tunneling, and while completing graduate school, Troy conducted research involving debris flows and slope stability hazard mitigation. Troy also began working for Lithos as a part time employee while earning his Master’s Degree, and strengthened his experience involving finite element modeling, slope stability analysis, and deliverable preparation. Troy has professional experience in construction observation, geotechnical quality control, materials testing, construction cost-estimation for tunnels and water conveyance infrastructure, as well as technical report and summary preparation.


adam pring, EI

Staff Engineer

Adam graduated with a bachelor’s degree in Geological Engineering and a minor in Underground Construction and Tunneling from Colorado School of Mines in 2015. He continued his education at Mines to earn a master’s degree in Engineering and Technology Management in 2016. Before joining Lithos, Adam worked as a munitions response geophysicist with a large environmental firm. His academic and professional experience include geophysical and geotechnical data collection, data interpretation, and data/engineering analysis. He is also an experienced technical and field team lead. Adam enjoys running, biking and hiking, and has recently taken up fly fishing.


Amber Hill, EI

Staff Engineer

Amber received a B.S. degree in Geological Engineering from the Colorado School of Mines in May 2018 with a minor in Underground Construction and Tunneling. During her time at CSM, she performed undergraduate student research in the UC&T program in post-emplacement tunnel subsidence, concrete tunnel ring deformation, and settlement of various materials above an installed tunnel. Outside the realm of UC&T, she performed slope and rock stability analyses using LiDAR technology and became familiar with mapping large-scale geological trends with respect to project design. Post-graduation, Amber worked with a general contractor to gain professional experience with construction observation and client collaboration. Her first contracting project involved the installation of storm and sewer pipeline via pipe-jacking while the second had her involved in concrete paving, earthworks, traffic control, and utility installation. Outside of work, Amber hikes, kayaks, camps, and rides dirt bikes with her friends and family.

2019 Lithos Summer Picnic