7
Based on the box plots the average of Cu concentra-
tions of Copper Flat mine tailings samples (porphyry cop-
per) at Hillsboro district is higher than the average of Cu
concentration of Magdalena district (carbonate-hosted)
samples and Black Hawk district (arsenide five-element
vein) mine waste samples (Figure 13).
Paste pH tests and Net Acid Generation graph
Static tests are geochemical analyses to predict the potential
of a waste sample to produce acid. The generation of acid in
sulfidic wastes can be determined by Acid Base Accounting
(ABA) and Net Acid Generation (NAG) tests. To enable
waste sorting, the NAGpH value is typically plotted against
the Neutralization Potential Ratio (NPR) value (Figure 14).
The Acid Potential (AP) is measured by analyzing the
sample for its sulfur content. The Neutralization Potential
(NP) is determined by analyzing the acidity consumption
of a sample in acid (HCl or H2SO4). Net Neutralization
Potential (NNP) gives the waste’s capacity to neutralize
any acid generated and is the difference between the Acid
Potential and the Neutralization Potential. The ratio NP/
AP, known as the Neutralization Potential Ratio (NPR)
(Lottermoser, 2010).
AP (kg CaCO3/tonnes) =wt.% S × 31.25
NP (total C) =wt.% C × 83.3
NNP =NP – AP,
NPR =NP/AP
Figure 11. Pb-Bi scatter plot of Black Hawk district mine
waste rock samples, Hillsboro district tailing samples, and
Magdalena district mine waste rock samples
Figure 12. Te-Cu scatter plot of Black Hawk district mine
waste rock samples, Copper Flat mine tailing samples at
Hillsboro district, and Magdalena district mine waste rock
samples
Figure 13. Box plots compare the copper (Cu)
concentrations of Black Hawk district mine waste rock
samples, Copper Flat mine tailing samples at Hillsboro
district, and Magdalena district mine waste rock samples
Figure 14. Combined ARD classification of Black Hawk
district mine waste rock samples, Copper Flat mine tailing
samples, and Magdalena district mine waste rock samples
Based on the box plots the average of Cu concentra-
tions of Copper Flat mine tailings samples (porphyry cop-
per) at Hillsboro district is higher than the average of Cu
concentration of Magdalena district (carbonate-hosted)
samples and Black Hawk district (arsenide five-element
vein) mine waste samples (Figure 13).
Paste pH tests and Net Acid Generation graph
Static tests are geochemical analyses to predict the potential
of a waste sample to produce acid. The generation of acid in
sulfidic wastes can be determined by Acid Base Accounting
(ABA) and Net Acid Generation (NAG) tests. To enable
waste sorting, the NAGpH value is typically plotted against
the Neutralization Potential Ratio (NPR) value (Figure 14).
The Acid Potential (AP) is measured by analyzing the
sample for its sulfur content. The Neutralization Potential
(NP) is determined by analyzing the acidity consumption
of a sample in acid (HCl or H2SO4). Net Neutralization
Potential (NNP) gives the waste’s capacity to neutralize
any acid generated and is the difference between the Acid
Potential and the Neutralization Potential. The ratio NP/
AP, known as the Neutralization Potential Ratio (NPR)
(Lottermoser, 2010).
AP (kg CaCO3/tonnes) =wt.% S × 31.25
NP (total C) =wt.% C × 83.3
NNP =NP – AP,
NPR =NP/AP
Figure 11. Pb-Bi scatter plot of Black Hawk district mine
waste rock samples, Hillsboro district tailing samples, and
Magdalena district mine waste rock samples
Figure 12. Te-Cu scatter plot of Black Hawk district mine
waste rock samples, Copper Flat mine tailing samples at
Hillsboro district, and Magdalena district mine waste rock
samples
Figure 13. Box plots compare the copper (Cu)
concentrations of Black Hawk district mine waste rock
samples, Copper Flat mine tailing samples at Hillsboro
district, and Magdalena district mine waste rock samples
Figure 14. Combined ARD classification of Black Hawk
district mine waste rock samples, Copper Flat mine tailing
samples, and Magdalena district mine waste rock samples