Twidwell, L.G.—Young, C.A., L.G. Twidwell, M. Bennett, Characterization of the Berkeley Pitlake I: Surface Waters, Preprint, SME 2007, Denver, CO 21 p.

Twidwell, L.G.—Hohn, J., L.G. Twidwell, R.G. Robins, A Comparison of Ferrihydrite and Aluminum Modified Ferrihydrite for Removing Arsenate by Co-Precipitation, Proceedings Iron Control in Hydrometallurgy, CIM, Montreal, 2006.

Twidwell, L.G.—Anderson, C.G., L.G. Twidwell, The Control of Iron and Arsenic in the Treatment of Gold Bearing Enargite Concentrates, Proceedings Iron Control in Hydrometallurgy, CIM, Montreal, 2006.

Twidwell, , L.G., C. H. Gammons, C. A. Young, R.B. Berg, Summary of Deepwater Sediment/Pore Water Characterization for the Metal-laden Berkeley Pit Lake in Butte, Montana. - Mine Water and the Environment, 25 (2): 86-92, Berlin, 2006.

Twidwell, L. G.—H.H. Huang, L.G. Twidwell, C.G. Anderson and C.T. Young, “Chemical Titration Simulation - An Equilibrium Calculation Approach”, The International Conference on Computational Analysis in Hydrometallurgy, 35th Annual Hydrometallurgy Meeting of CIM, Calgary, Alberta, Canada, August, 2005.

Twidwell, L.G.—Anderson, C.G., Olmstead, W., Twidwell, L.G., Young, C.A.,  “Fundamentals and Applications of Fire Assay”, CAMP Short Course, Butte, Montana, August 2005.

Twidwell, L.G.—Anderson, C.G., Miranda, P.J. and Twidwell, L.G., The TEMPER and Free Form Fabrication Titanium Initiatives at The Center for Advanced Mineral and Metallurgical Processing, USA  XITC 2005, China.

Twidwell, L.G.—Anderson, C.G., Miranda, P.J. and Twidwell, L.G., The TEMPER and Free Form Fabrication Titanium Initiatives at The Center for Advanced Mineral and Metallurgical Processing, USA  ITA Annual Meeting, Scottsdale, Arizona 2005.

Twidwell, L.G.—Anderson, C.G., Miranda, P.J. and Twidwell, L.G., The TEMPER and Free Form Fabrication Titanium Initiatives at The Center for Advanced Mineral and Metallurgical Processing, USA  SME Heavy Minerals, Jacksonville, Florida, 2005.

Twidwell, L.G., Berg, R., Young, C., “Deep Water Sediment/Pore Water Characterization from an Acidic Metal-Laden Pitlake” Proceedings 1st International Conference Advances in Mineral Resources Management and Environmental Geotechnology, MJMP&EP, June 7-9, Chania, Crete, Greece, Heliotopos Conferences, Athens, Greece (ISBN:960-88153-04) pp. 507-12.

Twidwell, L.—C. Anderson, L. Twidwell, J. Figueira, "Collaborative Activities between Montana Tech of The University of Montana and Akita University," International Symposium for Resource Science and Engineering of Rare Metals, August 25-27, 2004, Akita, Japan. 

Twidwell, L. G.—E. Dahlgren, L.G. Twidwell, S. McGrath, "Removal of Selenium from Mine and Waste Waters, Proceedings 1st International Conference Advances in Mineral Resources Management and Environmental Geotechnology," MJMP&EP, June 7-9, 2004, Chania, Crete, Greece, Heliotopos Conferences, Athens, Greece (ISBN:960-88153-0-4), pp 536-42. 

Twidwell, L. G., Berg, R., Young, C., "Deep Water Sediment/Pore Water Characterization from an Acidic Metal-Laden Pitlake," Proceedings 1st International Conference Advances in Mineral Resources Management and Environmental Geotechnology, MJMP&EP, June 7-9, 2004, Chania, Crete, Greece, Heliotopos Conferences, Athens, Greece (ISBN:960-88153-0-4), pp 507-12.

Twidwell, L. G., Huang, H. H., Hadden, G. A., "Investigation to Develop a Galvanically Enhanced Cementation Technology for Removing Oxyanions of Arsenic and Selenium from Minewaste Waters," EPA Mine Waste Technology Program, MWTP-213, 2004, MSE-Technology Applications, Butte, MT, 51 p.

Twidwell, L. G.—Huang, H., L.G. Twidwell, C.A. Young, Utilization of Calculational Programs to Demonstrate the Hydrometallurgical Treatment of Mercury Waste, Proceedings EPD Congress 2003, Eds. M. Schlesinger, TMS, Warrendale, PA. 

Twidwell, L. G., C. Williams-Beam, Removal of Thallium from Wastewater, Proceedings Hydrometallurgy 2003 (honoring I. Richie), August 2003, Vancouver, Canada, TMS Warrendale, PA. 

Twidwell, L.G.—Huang, H.H., C. Young, L.G. Twidwell, Utilization of Calculational Programs for Teaching Hydrometallurgy, Proceedings EPD Congress 2002, Eds. P. Taylor, TMS, Warrendale, PA, Feb. 2002. 

Twidwell, L.G.—Williams-Beam, C., L.G. Twidwell Technologies For Removing Thallium From Wastewater to Achieve Environmental Standards, Proceedings Recycling and Waste Treatment in Mineral and Metal Processing: Technical and Economic Aspects, Vol. 1, Eds. B. Bjorkman, C. Samuelsson, J. Wikstrom, Lulea, Sweden, June 2002, TMS Warrendale, PA, 2002, pp 713-24. 

Twidwell, L.G., C. Williams-Beam, Potential Technologies for Removing Thallium from Mine and Process Wastewater: An Abbreviated Annotation of the Literature, JEMEP, Vol 2, No. 1, 2002, pp 1-10. 

Twidwell, L.G., J. McCloskey, M. Gale-Lee, Removal of Hazardous Constituents from Wastewater, Proceedings Mineral Processing Plant Design, Control and Practice, Vol. 2, Eds. A.L. Mular, D.N. Halbe, D.J. Baratt, Vancouver, Canada, SME Litteton, CO., 2002, pp 1847-65.