2
contain any critical minerals in addition to those minerals
that are present in the deposit. Therefore, these mine wastes
could be as a potential resource of critical minerals.
Acid drainage, also known as acid rock drainage (ARD)
or acid mine drainage (AMD), occurs in mine waste rock,
tailings, and structures like pits and underground work-
ings. pH levels in mine waste can influence the mobility,
and availability of critical minerals. Some critical miner-
als could dissolve or leach more readily in acidic or alka-
line conditions (EPA, 1993). For instance, certain rare
earth elements (REEs) and metals like aluminum and
iron are more soluble in acidic environments. Therefore,
understanding the pH levels in mine waste is crucial for
assessing the potential release, and migration of critical
minerals (Plante et al., 2012 Shu et al., 2001). Paste pH is
a straightforward static test that determines whether stored
acidity is present in mine waste samples (Lapakko 2002,
European Commission 2009), which is used in this study.
New Mexico has more than 15,000 abandoned mine that
need re-evaluation of the critical mineral potential. There
is a need to classify these waste dumps to understand their
chemical composition, mineralogy, and to evaluate their
potential critical minerals value.
Black Hawk mine in Grant County, New Mexico
has produced silver from 1881 to 1960. This study aims
to characterize and estimate the critical minerals found in
the Black Hawk Mine wastes. In addition, this study will
determine the potential of acid mine drainage from the
Black Hawk mine wastes.
STUDY AREA
The Black Hawk district (also known as Bullard’s Peak
district), west of Silver City is an example of a 5-element
arsenide vein mineral system (Figure 2). Known critical
minerals in the district include Co, Ni, As, REE, Bi, W, Te,
fluorite and Zn. Mining began in the district in 1881 with
the discovery of the unusual silver-nickel-cobalt deposit at
the Alhambra mine (Gillerman and Whitebread, 1953).
Subsequent prospecting soon discovered additional
deposits. In 1920, pitchblende (uraninite) was recognized
in mine dumps in the area, and in 1949 the area became
of interest as a possible source of U, Ni, and Co. Types
of additional deposits found in the Black Hawk mining
district include: Laramide veins, W placer deposits, REE-
bearing episyenites and pegmatites. Total metal produc-
tion from 1881–1960 is estimated at 3,000 lbs Cu, 1,000
oz Au, 1,286,000 oz Ag, and 4,000 lbs Pb (McLemore et
al., 1996). In addition, 10,542 short tons of (2.7–71 %
WO3) tungsten ore (Richter and Lawrence, 1983 Dale
and McKinney, 1959) and 615 short tons of fluorspar ore
have been produced from the district (Williams, 1966
McAnulty, 1978).
Four mineral assemblages are reported at the Black
Hawk mine: 1) silver-argentite-uraninite-niccoliteram-
melsbergite, 2) silver-rammelsbergite-gersdorffitenickel
Figure 1. Periodic table showing critical minerals in New Mexico, as revised in 2022
(McLemore and Gysi, 2023)
contain any critical minerals in addition to those minerals
that are present in the deposit. Therefore, these mine wastes
could be as a potential resource of critical minerals.
Acid drainage, also known as acid rock drainage (ARD)
or acid mine drainage (AMD), occurs in mine waste rock,
tailings, and structures like pits and underground work-
ings. pH levels in mine waste can influence the mobility,
and availability of critical minerals. Some critical miner-
als could dissolve or leach more readily in acidic or alka-
line conditions (EPA, 1993). For instance, certain rare
earth elements (REEs) and metals like aluminum and
iron are more soluble in acidic environments. Therefore,
understanding the pH levels in mine waste is crucial for
assessing the potential release, and migration of critical
minerals (Plante et al., 2012 Shu et al., 2001). Paste pH is
a straightforward static test that determines whether stored
acidity is present in mine waste samples (Lapakko 2002,
European Commission 2009), which is used in this study.
New Mexico has more than 15,000 abandoned mine that
need re-evaluation of the critical mineral potential. There
is a need to classify these waste dumps to understand their
chemical composition, mineralogy, and to evaluate their
potential critical minerals value.
Black Hawk mine in Grant County, New Mexico
has produced silver from 1881 to 1960. This study aims
to characterize and estimate the critical minerals found in
the Black Hawk Mine wastes. In addition, this study will
determine the potential of acid mine drainage from the
Black Hawk mine wastes.
STUDY AREA
The Black Hawk district (also known as Bullard’s Peak
district), west of Silver City is an example of a 5-element
arsenide vein mineral system (Figure 2). Known critical
minerals in the district include Co, Ni, As, REE, Bi, W, Te,
fluorite and Zn. Mining began in the district in 1881 with
the discovery of the unusual silver-nickel-cobalt deposit at
the Alhambra mine (Gillerman and Whitebread, 1953).
Subsequent prospecting soon discovered additional
deposits. In 1920, pitchblende (uraninite) was recognized
in mine dumps in the area, and in 1949 the area became
of interest as a possible source of U, Ni, and Co. Types
of additional deposits found in the Black Hawk mining
district include: Laramide veins, W placer deposits, REE-
bearing episyenites and pegmatites. Total metal produc-
tion from 1881–1960 is estimated at 3,000 lbs Cu, 1,000
oz Au, 1,286,000 oz Ag, and 4,000 lbs Pb (McLemore et
al., 1996). In addition, 10,542 short tons of (2.7–71 %
WO3) tungsten ore (Richter and Lawrence, 1983 Dale
and McKinney, 1959) and 615 short tons of fluorspar ore
have been produced from the district (Williams, 1966
McAnulty, 1978).
Four mineral assemblages are reported at the Black
Hawk mine: 1) silver-argentite-uraninite-niccoliteram-
melsbergite, 2) silver-rammelsbergite-gersdorffitenickel
Figure 1. Periodic table showing critical minerals in New Mexico, as revised in 2022
(McLemore and Gysi, 2023)