Castle excavator in action


By ensuring the earthwork for your project is done to your specifications and according to your timeline, we take the risk out of your complicated urban excavation and utility work.

Castle’s experienced team is prepared for the specialized excavation work that comes along with complex sites. Our grasp of advanced technologies and history of taking on rigorous projects means we’re prepared for whatever challenges your site presents. And we can often identify those challenges before breaking ground!

Castle prepares sites for a wide range of facility types, including healthcare, education, office, industrial, warehouse, retail, multi-family housing, hospitality, cultural, athletic, renewable energy, wastewater treatment plants and more.

Castle’s earthmovers regularly provide the following services. 

National Park Service

Gateway Arch National Park — St. Louis, MO

National Park Service logo

Situation and Challenges:

Castle delivered sitework under four major contracts as part of the major revitalization of the Gateway Arch National Park, a five-year, $380 million program. Castle began its involvement with grading and excavation for the $10 million North Gateway, a seven-acre park with a natural amphitheater; continued with the $28 million complete renovation of the North and South Park Grounds; and completed with mass excavation and earthwork for the Gateway Arch Museum, a $96 million expansion of the subterranean museum.

Due to 150 years of prior building history on site, Castle performed subsurface utility mapping, including potholing and surveying, to provide the project team with accurate information on the identity and location of utilities to reduce conflict with unknowns on site during construction. The site required installation of 150,000 cubic yards of specialty soils that could not be over-compacted to ensure the integrity of the soil’s organic properties, so Castle utilized nontypical installation methods using small and lightweight equipment. Specialty soils included structural soils to support tree life and hardscapes, planting soils for ground coverings, and stabilizing soils for steeper banks/slopes.

Logistics were challenging, with multiple contracts and contractors working on the park, limited delivery pathways, and an active national monument. Large areas of existing grass and trees had to be protected while installing subsurface utilities in the middle, so the team minimized traffic to defined routes and barricaded off other areas. Two separate, uncharacteristic winter floods greatly impacted the work already put in place and limited work activities at times due to wet soils. A deep, vertical earth retention system allowed Castle to perform excavation and earthwork within a smaller footprint safely well beneath the bottom of the old museum.


Castle successfully supported installation of storm sewers, underdrain systems, sanitary sewers, water mains, underground electrical ductbanks, earthwork, grading, walls, pavement, planting soils, erosion control and slope stabilization, trees, shrubs, groundcovers, lawns, irrigation, furnishings, security measures, light fixtures, curbs, roads, ramps and stairs. Castle moved 300,000 cubic yards of dirt, hauling off approximately 80,000 cubic yards – the equivalent of 19 football fields with 10 feet of dirt each. Scope also included selective demolition and removal of existing furnishings, pavement, utilities, trees, shrubs, lawns, soils, and roads and provided protection of existing elements to remain.

The new park grounds now feature rehabilitated vegetation and landscaping, accessible pathways from the riverfront to the grounds, renovated reflecting ponds, upgraded lighting and new conveniences such as bike racks, drinking fountains and benches.

Saint Louis University

Spring Hall — St. Louis, MO

Saint Louis University logo

Situation and Challenges:

Spring Hall is a new $38 million, eight-story residence hall on Saint Louis University’s main campus. Castle performed subsurface utility mapping for the construction manager and identified multiple conflicts to the original site design. These included multiple utilities within the footprint of the planned residence hall and combined sewer reroute, multiple communications lines in direct conflict with the project, a traffic signal fiber line immediately adjacent to the proposed building face and an existing electrical vault with incorrect survey information.


Castle coordinated with utility companies for abandonment of conflicting infrastructure for 10 weeks, completed recommended relocations of communication lines over winter break prior to starting utility installations, and verified dimensions of the electrical vault to determine project impacts and constructability. The team performed demolition, mass excavation, utility reroute, storm line relocation with tunneling work, as well as backfill and subgrade around the building. Castle adhered to start times no earlier than 7 a.m., since students lived in the area, and implemented the project team’s logistics and safety plans to work efficiently and safely on the tight site.

As a result, Castle was able to deliver SLU significantly improved safety on the project, avoid six to 10 weeks of negative schedule impacts, save approximately $75,000 in construction costs, minimize costly crew downtime and proactively plan critical utility relocations.

Ameren Missouri

Rush Island Energy Center & Labadie Energy Center, Fly Ash Silo — Jefferson County & Franklin County, MO

Ameren logo

Situation and Challenges:

Castle was the civil contractor on the $58 million dry fly ash conveying and storage silo systems at Ameren's Labadie and Rush Island Energy Centers. The project was awarded on an Engineering Procurement and Construction (EPC) contract. Castle provided early budget assistance to the EPC team for the civil scope to help budget the project through the engineering phase.

Industrial sites such as energy centers are complex facilities with heavy infrastructure. To ensure quality and safe sitework, Castle “soft dug” the site prior to excavation to make sure live utilities were not encountered underground and also performed hydro-excavation on the perimeter of work areas before excavating. This is a non-destructive digging process utilizing water to safely expose potential underground utilities. Castle also met Ameren sloping and excavation standards for the plant, which are above and beyond industry standard.


In both locations the team successfully completed mass excavation, structural excavation and backfill, while performing drainage and roadway improvements. An electrical ductbank was relocated at Rush Island, and at the Labadie location, a live storm sewer was relocated and a new ductbank was installed.

The Boeing Company

Boeing Composite Center, Building 245 Expansion — St. Louis, MO

Boeing logo

Situation and Challenges:

Castle delivered a $9 million mass excavation project to support the design-build of a $141 million, 367,000-square-foot, high-bay building addition that houses manufacturing of composite materials for Boeing's commercial 777 aircraft.


Castle performed earthwork and excavation with reverence to the occupants on site, as the existing manufacturing building remained operational throughout all of construction. The team also performed services for the electrical contractor, including trenching, soil removal and backfill, compaction and directional boring for utility poles and electrical duct bank. The successful project included 142,000 cubic yards of export, grading, site demolition, soil remediation, storm and sanitary sewers, water service, bio-retention basins, subsurface utility mapping and installation of 2,800 linear feet of silt fence.

Topgolf International, Inc.

Topgolf — Chesterfield, MO

Topgolf logo

Situation and Challenges:

Castle provided civil construction for the new Topgolf, a 65,000-square-foot, three-story entertainment golf driving range with climate-controlled hitting bays for golf practice and instruction, restaurants, bars and event areas. In addition to sitework for the building, the 14-acre site features an outfield with 10 targets of various sizes constructed of heavy-gauge corrugated metal with manhole access. The outfield and parking lot required an underdrain system due to site conditions, including the nearby levee. Specialty soils were also required for fill in the seepage berm area. 


Castle installed storm, sanitary, and water utilities for the site, performed on-site grading of 30,000 cubic yards and imported 55,000 cubic yards of rock under the artificial turf for the whole outfield. Civil work was performed on time and on budget for the design-build project to support an August 2018 opening.

Washington University

East End Transformation of Danforth Campus — St. Louis, MO

Washington University in St. Louis logo

Situation and Challenges:

This $250 million campus transformation project encompasses eight individual project components, including three new academic buildings, an expansion of the Mildred Lane Kemper Art Museum, a welcome center, a multi-use building with dining and offices, an underground parking garage and an expansive new park. To get the overall fast-track schedule started on the right foot, Castle developed a detailed excavation plan that involved 110 trucks per day hauling out as many as 1,050 loads in two shifts. This activity equates to loading times of under one minute. The team utilized RFID tags to help track the number of trucks and their haul weight to manage the excavation as precisely as possible and maintain the production schedule. Caste also flew a drone daily during the initial heavy earthwork phase to help calculate earthwork production and inform the schedule. Crews worked two shifts, beginning at 6 a.m. and ending at 10:30 p.m.


Castle performed a 21-acre mass excavation, removing and hauling away 330,000 cubic yards of dirt. Castle then placed 65,000 cubic yards of soil backfill around four new buildings and a multiple level underground garage. The team also supported the installation of 11,500 linear feet of sewers up to 26 feet in depth, 110 manhole structures, one major lift station and 4,500 linear feet of water main lines. Castle also performs traffic control on the site, a major effort for a busy university campus located in a dense, high-traffic residential environment next to a light rail line and the iconic Forest Park in St. Louis.

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