We are driven by a desire to serve our communities with geotechnical and geological experience, and create smart, buildable design solutions.
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.
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
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
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 HEYER, PE
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.
Evan Friedman, PE, PG
Evan is a professional civil engineer and geologist with a wide range of project experience, primarily focused in geological and tunnel engineering for infrastructure design, evaluation, and rehabilitation. His experience consists of technical and project/task management roles on a variety of projects including inspection, condition assessment, and rehabilitation of underground infrastructure; tunnel excavation and support design; slope and near surface excavation stability analysis and design; risk assessment; geotechnical site investigations; geologic hazard assessment; forensic geotechnical studies; distressed foundation repair; laboratory testing of soil, rock, and concrete; and aggregate and cement source investigations
Amara Meier, EI
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
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.
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.