J.M.W. Geo-Consulting


We are a service-oriented firm located close to Amsterdam, the Netherlands, providing multi-disciplinary services in the fields of economic geology, natural stone analysis, and environmental examination.

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About the company

J.M.W. Geo-Consulting was set up by Dr. J.M. Warnsloh in January 2009 to deliver services in mineral exploration and petrography. Our core business is consultancy in the fields of economic geology, natural stone analysis, and environmental examination. Over the years, the focus of our activities shifted from general services during exploration projects to detailed petrographical and geochemical analyses as base for mineral resource estimations following Ni 43-101 and JORC. Around this core, we serve clients with microscopical, geochemical and x-ray analyses of geomaterials like natural stone, concrete and metallurgical products.

We offer our services for all phases of your project:

  1. evaluation or (pre)feasibility studies (e.g. literature studies, availability studies)
  2. sampling during the mapping or exploration campaigns
  3. analysis of samples or data with our in-house equippment
  4. presentation of the data in reports or publications

Key staff member

Dr. J.M. Warnsloh is a graduate mineralogist with 15+ years experience in petrology, economic geology and applied geochemistry. He holds a MSc in economic geology and geochemistry ( Department of Mineral Resources, Clausthal University of Technology) and a doctorate degree in applied geochemistry (Institute of Mineralogy and Economic Geology, RWTH Aachen University).
He accomplished projects in economic geology (focus on niobium and tantalum mineralization), mineralogy for mining and process metallurgy companies, petrographic examinations of natural stones, as well as mineral exploration campaigns. He has demonstrated skills in drilling supervision, core logging and quality control and gained a high expertise in the field of niobium mineralization and carbonatite-hosted commodities (e.g. Niobium, REE).

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Our Services in a nutshell...


We look at you project and decide which steps have to be taken and which analyses should be done. This first step also includes datamining and literature research.


We assay during a sampling campaign or use your provided samples. This step also includes description of cutting and drill cores during the drilling phases, as well as determination of sample intervals for chemical analysis and sorting tests


We analyse the samples with our in-house equipment (polarising microscope, ore microsocope and pXRF) or let the measurements be done by one of our affiliated companies and research institutions, and evaluate the generated data afterwards.


We summarise and present our generated data in form of reports, lectures or publications and give advice, if required.