Company lists · Data refreshed September 2026

Top 25 Subsurface technical consulting firms worldwide

Name: Subsurface technical consulting firms worldwide
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 29, 2026 8,365 companies tracked

RevenueBase identified 8,365 subsurface technical consulting firms worldwide as of September 2026 and tracks 127,114 professional contacts across them, including 38,734 with verified work emails. The United States is the largest market and Belo Horizonte the largest hub.

This list covers subsurface technical consulting firms worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 29, 2026. Country and city lists for subsurface technical consulting firms follow the table.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 29, 2026 86% judged on-target in blind review

8,365Companies

127,114Contacts tracked

38,734Verified emails

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The 25 largest subsurface technical consulting firms worldwide

Ranked by team size

Top 25 of 8,365 subsurface technical consulting firms worldwide, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to subsurface technical consulting firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Terracon	Partial evidence	Olathe, KS, United StatesHQ checked Sep 29, 2026	5,001-10,000	6,113 contacts →
	Partial evidence “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Source: RevenueBase Database · checked Sep 29, 2026
2	Keller	Indirect evidence	London, United KingdomHQ checked Sep 29, 2026	5,001-10,000	3,960 contacts →
	Indirect evidence “Every day, people around the world live, work and play on ground prepared by Keller, the world's largest geotechnical specialist contractor.” Source: RevenueBase Database · checked Sep 29, 2026
3	SRK Consulting	Partial evidence	Vancouver, CanadaHQ checked Sep 29, 2026	1,001-5,000	2,259 contacts →
	Partial evidence “SRK Consulting is an independent, international group providing specialised consultancy services.” Source: RevenueBase Database · checked Sep 29, 2026
4	ECS Group Of Companies	Partial evidence	Chantilly, VA, United StatesHQ checked Sep 29, 2026	1,001-5,000	2,210 contacts →
	Partial evidence “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Source: RevenueBase Database · checked Sep 29, 2026
5	Major Drilling	Indirect evidence	Moncton, NB, CanadaHQ checked Sep 29, 2026	1,001-5,000	1,447 contacts →
	Indirect evidence “Major Drilling Group International Inc.” Source: RevenueBase Database · checked Sep 29, 2026
6	Knight Piesold	Partial evidence	Denver, CO, United StatesHQ checked Sep 29, 2026	1,001-5,000	1,231 contacts →
	Partial evidence “Knight Piésold is an employee-owned, global consulting firm providing specialist services to the mining, power, water resources, and infrastructure industries.” Source: RevenueBase Database · checked Sep 29, 2026
7	Capital Limited	Indirect evidence	Mauritius, AustriaHQ checked Sep 29, 2026	1,001-5,000	994 contacts →
	Indirect evidence “Capital Limited is a leading service provider for the exploration and mining industry.” Source: RevenueBase Database · checked Sep 29, 2026
8	GZA Geoenvironmental, INC	Indirect evidence	Norwood, MA, United StatesHQ checked Sep 29, 2026	501-1,000	880 contacts →
	Indirect evidence “Founded in 1964 as a soils and foundations specialty consultant, GZA GeoEnvironmental, Inc.(GZA) has grown into a full-service company providing its clients with highly…” Source: RevenueBase Database · checked Sep 29, 2026
9	Klohn Crippen Berger	Partial evidence	Vancouver, BC, CanadaHQ checked Sep 29, 2026	501-1,000	871 contacts →
	Partial evidence “KCB is a global engineering, geosciences, and environmental consulting firm driven by Passion, Integrity and a commitment to Excellence.” Source: RevenueBase Database · checked Sep 29, 2026
10	BGC Engineering INC	Partial evidence	Vancouver, BC, CanadaHQ checked Sep 29, 2026	501-1,000	798 contacts →
	Partial evidence “BGC Engineering is an international consulting firm that provides professional services in applied earth sciences.” Source: RevenueBase Database · checked Sep 29, 2026
11	AGR	Strong evidence	Oslo, NorwayHQ checked Sep 29, 2026	501-1,000	768 contacts →
	Strong evidence “AGR – an Aqualis company – is a multidisciplinary consultancy, specialising in drilling & wells, subsurface, marine and subsea solutions, resourcing, technical safety and software…” Source: RevenueBase Database · checked Sep 29, 2026
12	Integral S.A. Ingenieros Consultores	Indirect evidence	Medellín \| Bogotá \| Lima \| Miami \| Nueva Delhi, ColombiaHQ checked Sep 29, 2026	1,001-5,000	709 contacts →
	Indirect evidence “Over six decades offering our consultancy services locally and internationally, based on ethical principles and commitments, always through honest, socially responsible actions…” Source: RevenueBase Database · checked Sep 29, 2026
13	Seequent	Partial evidence	Christchurch, New ZealandHQ checked Sep 29, 2026	501-1,000	696 contacts →
	Partial evidence “Seequent, The Bentley Subsurface Company, helps organisations to understand the underground, giving them the confidence to make better decisions faster.” Source: RevenueBase Database · checked Sep 29, 2026
14	Raba Kistner, INC	Indirect evidence	San Antonio, TX, United StatesHQ checked Sep 29, 2026	501-1,000	582 contacts →
	Indirect evidence “Founded in 1968, Raba Kistner Inc.” Source: RevenueBase Database · checked Sep 29, 2026
15	Nova Engineering And Environmental, LLC	Partial evidence	Kennesaw, GA, United StatesHQ checked Sep 29, 2026	501-1,000	518 contacts →
	Partial evidence “Established in 1996, NOVA was originally founded to provide Environmental Consulting, Geotechnical Engineering, and Construction Materials Testing and Inspection services to the…” Source: RevenueBase Database · checked Sep 29, 2026
16	Geotec	Indirect evidence	Ate, BelgiumHQ checked Sep 29, 2026	1,001-5,000	504 contacts →
	Indirect evidence “Geotec S.A, empresa de perforación perteneciente a Boyles Bros, fue fundado en 1963 posicionándose como una empresa líder en la industria minera peruana.” Source: RevenueBase Database · checked Sep 29, 2026
17	Entact, LLC	Indirect evidence	Westmont, IL, United StatesHQ checked Sep 29, 2026	501-1,000	483 contacts →
	Indirect evidence “ENTACT is the partner of choice in solving our customer's most complex environmental remediation and geotechnical infrastructure challenges.” Source: RevenueBase Database · checked Sep 29, 2026
18	Thurber Engineering LTD	Indirect evidence	Edmonton, AB, CanadaHQ checked Sep 29, 2026	501-1,000	480 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 29, 2026
19	Geoengineers INC	Indirect evidence	Redmond, WA, United StatesHQ checked Sep 29, 2026	201-500	479 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 29, 2026
20	ERG Engenharia	Indirect evidence	Belo Horizonte, BrazilHQ checked Sep 29, 2026	201-500	477 contacts →
	Indirect evidence “Empresa mineira, fundada em 1988, a ERG Engenharia mantém vivo o seu ideal de participar da construção de um mundo melhor e sustentável.” Source: RevenueBase Database · checked Sep 29, 2026
21	GEO	Indirect evidence	Kgs. Lyngby (copenhagen), DenmarkHQ checked Sep 29, 2026	201-500	468 contacts →
	Indirect evidence “Founded in 1943, Geo is a market leading engineering consultancy company and contractor, specialised within the fields of geotechnical and environmental engineering (geoteknik og…” Source: RevenueBase Database · checked Sep 29, 2026
22	Douglas Partners	Indirect evidence	West Ryde, AustraliaHQ checked Sep 29, 2026	501-1,000	466 contacts →
	Indirect evidence “Welcome to Douglas Partners Pty Ltd, a leading engineering consultancy specialising in geotechnics, rock mechanics, environment, groundwater, earthworks and geophysics.” Source: RevenueBase Database · checked Sep 29, 2026
23	Anddes	Indirect evidence	Santiago De Surco, PeruHQ checked Sep 29, 2026	201-500	462 contacts →
	Indirect evidence “En Anddes nos especializamos en brindar servicios de asesoría y consultoría para el desarrollo y supervisión de proyectos ambientales, electromecánicos, civiles y de construcción…” Source: RevenueBase Database · checked Sep 29, 2026
24	Geo-Technology Associates, Inc. GTA	Indirect evidence	Abingdon, MD, United KingdomHQ checked Sep 29, 2026	501-1,000	460 contacts →
	Indirect evidence “Geo-Technology Associates, Inc.(GTA) proudly celebrates more than 40 years of service, backed by a team of 600+ professionals-including geotechnical engineers, environmental…” Source: RevenueBase Database · checked Sep 29, 2026
25	AKD International	Indirect evidence	PanamaHQ checked Sep 29, 2026	201-500	452 contacts →
	Indirect evidence “AKD® International es el Aliado Estratégico de toda Empresa de Minería, Energía y/o Petróleo en Latinoamérica que busca un Experto en Perforación con Gran Amor por lo que hace y…” Source: RevenueBase Database · checked Sep 29, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: subsurface technical consulting firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names subsurface technical consulting firms.
Partial evidence: Its own public description names part of subsurface technical consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name subsurface technical consulting firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 8,365 subsurface technical consulting firms worldwide

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Subsurface technical consulting firms worldwide at a glance

As of Sep 29, 2026

30.5%Verified-email coverage

15.2Average contacts per company

1-10Median size (employees)

1.4%Largest-city concentration · Belo Horizonte

Sep 29, 2026Page data refreshed

Companies by employee count

1-10

4,486

11-50

2,685

51-200

868

201-500

195

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency is reported on each country list linked below.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among subsurface technical consulting firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
Coverage: Every country. Country and city lists for subsurface technical consulting firms are linked below.
What qualifies: Companies worldwide whose own description of what they do matches “subsurface technical consulting firms”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names subsurface technical consulting firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among subsurface technical consulting firms, and records with no verified work email.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 38,734 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 29, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Subsurface technical consulting firms by location

46 lists · largest first

Every Subsurface technical consulting firms list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names subsurface technical consulting firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many subsurface technical consulting firms are there worldwide?

RevenueBase identified 8,365 subsurface technical consulting firms worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Terracon, headquartered in Olathe, tops this list with the largest team on record.

Which country has the most subsurface technical consulting firms?

The United States leads with 1,264 companies, followed by Brazil (650) and Canada (456). Every subsurface technical consulting firms list by country and city is linked on this page.

Which city has the most subsurface technical consulting firms?

Belo Horizonte leads with 115 headquartered companies, followed by Houston (88) and Sao Paulo (81).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 38,734 verified decision-maker contacts tracked across these 8,365 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 29, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.