Statement of Qualifications Mining Water Balance

Statement of Qualifications Mining Water Balance Modeling ater supply, distribution and management are critical to the operation of all mines. Water monitoring and tracking assists in water use optimization. Water (balance) modeling is a valuable tool for documenting the operation of mine water systems and for tracking water supplies, use, and consumption. Once developed, water models can be used to evaluate water related advantages/disadvantages associated with proposed operational changes, expansions, permitting, and mine closure studies. HydroGeoLogica specializes in mine water models for: Water 
Pre‐feasibility 
Feasibility 
Operations 
Expansion studies 
Facility (tailings impoundments, leach pad) studies 
Site‐wide water management 
Pit lake modeling (see associated SOQ) 
Permitting 
Closure model construction involves the development of a RDA Pond Drain-down (1st year of closure)
Mine Closure Water Balance
Conceptual Model
Precip.
RDA
Runoff
Evap.
Catchment
Runoff
Tailings
Runoff (< 2 yrs of closure)
Collected Seepage (<10 yrs of closure)
CN Destruct
Treatment Plant
conceptual model of operational Seepage
RDA Runoff (>2 yrs after closure)
Collected Seepage
(>10 yrs after closure)
RDA R4 Pond Drain-down
(1st year of closure)
conditions. Operational changes Catchment
Runoff
Catchment
Runoff
are continual during the active Precip.
Precip.
Evap.
RDA
Runoff
Evap.
Catchment
Runoff
Tailings
Reservoir
Reservoir pond (drained during first
6 months of closure) and throughflow
Evap.
(Breached at closure)
Seepage
RDA Runoff and
Collected Seepage
WRD
Runoff
Diversion Pond
phase of mine life. It is therefore Precip.
Precip.
Evap.
WRD A
important to maintain Outflow
CN Destruct
discharge
Seepage
to North Pit
From IWS
operational water balance models Precip.
Evap.
Precip.
NP overflow
At 230m RL
Catchment
Runoff
Evap.
Catchment
Runoff
Pit Wall
Runoff
WRD Runoff
North Pit
WRD Runoff
to North Pit
WRD B
Seepage
Groundwater
Inflow
South
Pit
Groundwater
Outflow
Groundwater
Inflow
Seepage
to IWS
WRD Runoff
to South Pit
Precip.
Evap.
Groundwater
Outflow
WRD Runoff
to South Pit
-456m RL
WRD Runoff
WRD C
Precip.
Intermediate
Water Storage
Pit Wall
Runoff
-252m RL
Seepage to
groundwater
IWS discharge to
ARD Treatment Plant
(<20 yrs after closure)
IWS discharge (>20 yrs
after closure)
SP overflow
At 235m RL
Drainage
Channel
Precip.Evap.
ARD Treatment
Plant
regularly so that they represent current conditions
Catchment
Runoff
WRD
Runoff
Seepage to IWS
Stockpile
Footprint
Runoff
Evap.
Seepage to
groundwater
Medium Grade
Seepage to IWS
Stockpile Footprint
Discharge
HGL SOQ 2012 ‐ Mine Water Balance Modeling Page 2 The conceptual model is used to develop a numerical model in GoldSim. Leach Pad
Supporting Data
3.14
16
3.14
16
3.14
16
Total_Pad_Area
Leach_Pads_Catchment_Area
Active_Leaching_Area
3.14
16
Outflows
Inflows
3.14
16
Irrigation_Rate
X
X
X
X
Active_Leach_Evaporation
Dry_fraction_Evap
X
X
Leach_Pad_Precip
Cross check.
Should be about
10%
Wet_fraction_of_Active_IrrArea
Wetting
Leach_Pad
X
X
PLS_out_of_Pad
Leach_Pad_Inflows
Leach_Pad_Outflows
HydroGeoLogica, Inc.
414 Garden Glen Ct., Golden, CO 80403
www.hydrogeologica.com
HGL SOQ 2012 ‐ Mine Water Balance Modeling Page 3 ‘Dashboard’ controls can be built into GoldSim water models and customized to allow users to evaluate ‘what if?’ scenarios. Measured and calculated flow rates from the water model can be displayed on a flow diagram in Excel for ease of use. Water Model ‐ Diagram of Average Flows
Period for Averaging
FROM 10/1/2012
TO 10/31/2012
GROUNDWATER SUPPLIES
SURFACEWATER SUPPLIES
10 gpm
Groundwater Supply
3000 gpm
1000 gpm
Pump Station
40 gpm
50 gpm
Water
Tank
Losses
800 gpm
Evaporative
Losses
Fill Stand
Miscellaneous
consumptive
uses
1000 gpm
Booster
250 gpm
100
gpm
Treatment
Plant
Crusher
390 gpm
1800 gpm
MILL
200
gpm
Dust Supression
Conveyor
Mill
Pond
75 gpm
SX-EW / LEACHING
60 gpm
800 gpm
Distribution
Tank
Mill
Floatation
Circuit
Overflow
100 gpm
500
gpm
(Reclaim)
Losses
Processing
Losses
Losses
in
Concentrate
Concentrate
(shipped)
50
gpm
Dust Supression
EW
Well
Tailings
Thickener
Bypass
flow
40 gpm
8000 gpm
950 gpm
6000 gpm
TAILINGS
Seldom used
Bypass
(as needed)
Aggregate
Raffinate Pond
Local
Wells
Storage
Pond
1000 gpm
7950 gpm
PLS
8000 gpm
Aggregate
PLS Pond
50 gpm
9500 gpm
Pit
Dewatering
Aggregate
Leach Pad
Soak Up
Reclaim
Tank
Reclaim
500 gpm
Wetting and Irrigation
OverFlow
Tailings
Fill Stand
SX
Mill
Grinding
Cooling and Dust
Suppression Losses
40
gpm
550
gpm
1100 gpm
Seepage
Return Pond
Wells
Tailings
Reclaim
Pond 1
Upset conditions only
Tailings
20 gpm
Seepage
Collection
Wells
Well
Collection
system
Seepage
Return Pond
Tailings
Reclaim
Pond 3
6200 gpm
550 gpm
Tailings Reclaim
Pond 2
Dust Supression
100
gpm
Uncollected Seepage
HydroGeoLogica, Inc.
414 Garden Glen Ct., Golden, CO 80403
www.hydrogeologica.com
5000 gpm
HGL SOQ 2012 ‐ Mine Water Balance Modeling Summaries of Selected Projects: Page 4 Zonia Mine, Arizona – Redstone Resources Corporation Facility specific water balances were developed in GoldSim to evaluate operational conditions associated with a proposed pit and proposed heap leach pad. These water balances were then used as the foundation for closure water balances of these facilities. Standardized Water (Balance) Modeling for Multiple Mine Sites ‐ Freeport‐McMorRan Copper and Gold Standardized water (balance) modeling techniques were developed and documented. Freeport McMoRan was then able to direct a number of consulting companies to develop water models using these guidelines so that the models would be of a similar format, and would be customized to meet the needs of the parent company. This standardized approach to mine water modeling allows easy comparison of water use data between mine sites, and is helpful for larger, multi‐site and international mining companies. Bagdad and Safford Mines, Arizona ‐ Freeport‐
McMorRan Copper and Gold Development and maintenance of stochastic dynamic systems models representing operational mine water management using GoldSim. The models are used to evaluate climate related water supply issues and mine water management and facility development alternatives. Training of site staff for operation and maintenance of the models was also provided. Martabe Mine feasibility study, Indonesia ‐ Oxiana A stochastic dynamic systems model of site‐wide mine water management was developed in GoldSim for a gold mine feasibility study. The model includes a synthetic precipitation generator, power and equipment failure frequencies, and 14 site facilities including two fresh water dams, four containment dams, two ore stockpiles, an ore processing facility, a pit, and a water treatment plant. The proposed mine is located in the headwaters of a river which is heavily used downstream as a water supply. The site design was developed in order that the mine would be compliant with the U.S. Cyanide Code, so the output was used to demonstrate the likelihood, frequency and magnitude of any possible releases of untreated water from the site. The model was used to evaluate mine water management alternatives and to predict water storage in various facilities. Calculated inflows and outflows from the various facilities were used as input parameters to hydrochemical modeling (in Phreeq) based on the quality of each influent water type. Supporting chemical mass balance calculations were successfully performed within GoldSim for certain parameters. Changes in water quality at the various water storage facilities throughout the mine life were predicted. Tenke Mine, Democratic Republic of Congo (DRC) ‐ Freeport‐McMorRan Copper and Gold Conceptual model development and dynamic systems modeling was performed in support of water use accounting and optimization for the mine tailings operations. The model was designed to be used for deterministic or stochastic predictions of water demand based on climate scenarios. A ‘player’ version of the model was provided to allow mine staff to operate the model (to evaluate user‐defined scenarios and view results without direct knowledge of GoldSim). Goldsim and site‐specific‐model training were also provided, together with documentation and ongoing model support. Mt. Todd Project, Northern Territory (NT), Australia ‐ Vista Gold Australia Conceptual model development and dynamic systems modeling was performed in support of evaluating the water balance for the proposed mine expansion and redevelopment project, in support of pre‐feasibility analysis. The life of mine model included all aspects of mine water usage from pre‐
development through the operational period; the model included pit dewatering, tailings facility water balance, heap leach facility and ponds, waste HydroGeoLogica, Inc.
414 Garden Glen Ct., Golden, CO 80403
www.hydrogeologica.com
HGL SOQ 2012 ‐ Mine Water Balance Modeling rock piles, and several stormwater ponds. A separate model was developed to evaluate closure scenarios, including water treatment, and develop the most practical and efficient closure plan; the closure model was evaluated using a stochastic climate generator to evaluate the effects of long‐
term climate variation. Haile Mine Pre‐Feasibility Study, South Carolina ‐ Romarco A stochastic dynamic systems model was developed using GoldSim to evaluate water management alternatives for a proposed multi‐pit gold mine. The model includes several pits, water transfer facilities, water storage facilities and other mine facilities together with intermittent power and equipment failures. Power failures were correlated to extreme weather events. The model was used to verify availability of water on site to operate the mill, to estimate required water treatment rates, and to ensure that the mine design was compliant with U.S. Cyanide Code. Waters of different qualities were tracked across the site so they could be managed separately. Intermittent power and equipment failures were simulated and were correlated to extreme weather events. Johnson Camp, copper mine, Arizona – Nord Resources Corporation A dynamic systems model was developed in GoldSim to simulate flows within several leach circuits at the mine. 16 site facilities are simulated. The model is designed to allow users to evaluate leach pad loading alternatives and irrigation plans, and optimize solution management during operations. Input data are stored in spreadsheets and results are exported to spreadsheets to allow mine staff to operate the model and view results without direct knowledge of GoldSim. Marlin Mine, gold mine, Guatemala ‐ Goldcorp A dynamic systems model of mine water and tailings management was developed in GoldSim to predict water and tailings storage needs for changing ore production rates. The model was calibrated to Page 5 existing site data and then used for predictive purposes. On‐site GoldSim training for mine personnel was provided so that the model calibration could be updated and water management procedures within the model modified as necessary. Gaby Mine feasibility study, Ecuador ‐ Codelco The project consisted of development of a dynamic systems model using GoldSim to evaluate potential mine designs. Model predicted operational and closure issues for various mine design alternatives to ensure the mine operated as a zero discharge facility. Water storage and treatment requirements were optimized. Kori Chaca Mine, Bolivia ‐ Inti Raymi (controlled by Newmont) A stochastic dynamic systems model (water balance) was developed using GoldSim to evaluate pit filling options for mine closure including timing and water quality issues. The possibility of encapsulating mine waste in highly saline water at the bottom of the pit was evaluated. The water balance included mass‐balance water quality calculations to evaluate the likely salinity of the pit lake and the stability of pit lake stratification and continued waste encapsulation into the future. Boddington Gold Mine, Australia ‐ Newmont A stochastic dynamic systems model (water balance) was developed using GoldSim to evaluate options for mine water disposal and management at closure. The mine includes two pits, two tailings storage facilitie, a number of waste rock storage facilities and several water storage dams. Operational changes throughout the closure period, such as the installation of cover systems on closed facilities (TSFs and waste dumps), operation and closure of treatment plants, decommissioning of dams etc are simulated in the model. Mass balance chemistry was also developed within the GoldSim model to calculate and track changes in the concentrations of chloride and sulfate at various locations in the system. HydroGeoLogica, Inc.
414 Garden Glen Ct., Golden, CO 80403
www.hydrogeologica.com