Five easy pieces

Case studies that implement models for better characterization and remediation

Kirk Nordstrom and Ann Maest

The short course will dis­cuss five mine sites, all with very dif­fer­ent geo­lo­gic and geo­chem­ic­al char­ac­ter­ist­ics, and will show how mod­els can and have been applied to these sites. Instead of start­ing with basic prin­ciples and show­ing some examples, this course will start with real examples of mine waste and mine water chal­lenges. The mines will include:

1. Buck­horn Mine, Wash­ing­ton State, USA
2. Iron Moun­tain Mines, Cali­for­nia, USA
3. Odiel/Rio Tinto, Iberi­an Pyr­ite Belt, Por­tugal and Spain
4. Questa Mine, New Mex­ico, USA
5. Berke­ley Pit, Montana, USA

The course is pro­posed to be one day in length. Each case study will cov­er the fol­low­ing top­ics:

• Geo­lo­gic and geo­chem­ic­al descrip­tion
• Pre-min­ing (“nat­ur­al”) back­ground
• Min­ing his­tory
• Geo­chem­ic­al char­ac­ter­iz­a­tion
• Mod­el­ing approaches and res­ults
• Dis­cus­sion of integ­rated atmo­sphere-sur­face water-ground­wa­ter mod­el­ing
• Inter­est­ing geo­chem­ic­al pro­cesses affect­ing mod­el­ing (e.g., Fe photore­duc­tion)
• Suc­cesses and chal­lenges of mod­el­ing
• Using mod­el­ing to select the most effect­ive remedi­al meas­ures
• Les­sons learned.

Facil­it­at­ors will be using the PHREEQCi code (ver­sion 3.7.3), and par­ti­cipants may down­load a free copy at https://water.usgs.gov/water-resources/software/PHREEQC/index.html. Make sure it is the Graph­ic­al User Inter­face ver­sion not the batch ver­sion. How­ever, this course is not about learn­ing how to use the code, and some exper­i­ence is assumed. Using PHREEQC is not essen­tial for the course, and oth­er codes could also be used.

Par­ti­cipants are expec­ted to know:

• What sat­ur­a­tion indices are
• Some gen­er­al chem­istry about acid mine drain­age
• Some gen­er­al min­er­alogy about pre­cip­it­ates from acid mine drain­age
• Some gen­er­al inform­a­tion about min­ing and min­er­al pro­cessing.

Each case study will demon­strate how mine site char­ac­ter­iz­a­tion and mod­el­ing are used and how a good under­stand­ing of basic geo­chem­ic­al prin­ciples is needed. Attendees will leave the course with an improved under­stand­ing of the advant­ages and pit­falls of apply­ing geo­chem­ic­al and hydro­geo­lo­gic mod­els to mine sites and how using such mod­els can res­ult in more effect­ive remedi­ation.