• Symposium on Mine Water and Environmental Impacts, Johannesburg, Republic of South Africa, 7-13 September 1998.

• PTFI Modeling Training Workshop, Instructed by Elfadil Azrag, HCI, Tembagapura, Irian Jaya, Indonesia August 1998.

• Hydraulics Division of the American Society of Civil Engineers 1993 Conference, San Francisco, USA, 25-30 July 1993.

• Computational Methods in Water Resources IX Conference, Denver, USA, June 1992.

•   International Course on Urban Drainage in Developing Countries, Essen, Federal Republic of Germany, November 12-30, 1990.

• Seminar in Natural Coagulants in Water Treatment, Yogyakarta, Indonesia, October 1989 .

• Microbiological for Sanitary Engineers: Application to Wastewater treatment Plants Operation, University of Leeds, Leeds, UK, May 1988.

Research and Development within HCI:

MINEDW and FEMCAD Code development

Scope: HCI has developed a state-of-the-art, three-dimensional, finite element ground-water flow code to simulate mine dewatering in complex hydrogeologic systems. This code, designated MINEDW, can be used to:

• Estimate passive inflows (i.e., with no active dewatering facilities such as wells in operation) to pits and under­ground openings under two-regime (i.e., both laminar and non-laminar) flow conditions,

• Evaluate potential effects of alternative active dewatering systems,

• Simulate the infilling of a “pit lake” after mining and dewatering cease,

• Predict local and regional environmental impacts of dewatering, and

• Estimate the height of seepage faces in pit highwalls to assist in evaluation of slope stability.

Role: Currently I am the custodian of the program within HCI. MINEDW was original written by Timothy J. Durbin I verified, tested, and modified the original code to handle more diverse hydrologic feature among the important changes that I included in the code:

• Collapsing grid to handle gradual pit excavation.

• Simulation of high-flow and high-pressure drill holes usually in the underground mine workings.

•  Routing of natural streams networks where interaction with ground-water is a function of stage within the stream and head in the aquifer.

• Introduction of “mass lumping” technique versus “the consistent solution”

• Incorporation of 3-D full conductivity tensor.

•  Incorporation of solution for large diameter wells and simulation of inundated mine’s underground workings.

•  Incorporation of dynamically changing hydraulic properties of rock mass.

•  Simulation of non-linear (non-Darcian) flow in the modeled faults.