Grade and Tonnage Model for Tungsten Skarn Deposits—2020 Update

Scientific Investigations Report 2020-5085
By: , and 



This report presents an updated grade and tonnage model for tungsten skarn deposits. As a critical component of the U.S. Geological Survey’s three-part form of quantitative mineral resource assessment, robust grade and tonnage models are essential to transforming mineral resource assessments into effective tools for decision makers. Using the best data available at the time of publication, this represents the first attempt in nearly 30 years to capture current mineral inventory and cumulative production data for worldwide tungsten skarn deposits. The accuracy of modern assessments of undiscovered tungsten skarn resources is highly influenced by the use of current data on the distribution of the grades and tonnages of well-explored tungsten skarn deposits. Primary factors affecting the changes to these distributions in the model presented here compared with those of previous models are the inclusion of important deposits, especially those in China that had been omitted in previous models; expanded mineral inventories resulting from increased exploration; and changes to international reporting standards. These factors have resulted in dramatic increases in average ore tonnage and slight decreases in the average grade of tungsten skarn deposits compared with previous models. Large increases in contained metal are observed among many of the individual deposits incorporated within this model that were also included in previous tungsten skarn grade and tonnage models. This report also provides recommendations for input parameters related to grade and tonnage models to use with software tools designed to facilitate the three-part form of quantitative mineral resource assessments.

Suggested Citation

Green, C.J., Lederer, G.W., Parks, H.L., and Zientek, M.L., 2020, Grade and tonnage model for tungsten skarn deposits—2020 update: U.S. Geological Survey Scientific Investigations Report 2020–5085, 23 p.,

ISSN: 2328-0328 (online)

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Assessment Methods
  • Descriptive Models
  • Previous Grade and Tonnage Models
  • Methods
  • Results
  • Discussion
  • Conclusion
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Grade and tonnage model for tungsten skarn deposits—2020 update
Series title Scientific Investigations Report
Series number 2020-5085
DOI 10.3133/sir20205085
Year Published 2020
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Eastern Mineral and Environmental Resources Science Center
Description vi, 23 p.
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details