Mercury Mines in Europe
53
Only in the past few years has remote sensing LIDAR (light detection and
ranging) technique been applied to mercury detection (Edner et al. 1992, 1993,
1994; Ferrara et al. 1992). This has for the first time made possible a reliable
evaluation of mercury emissions from both point sources and extended ones.
With this technique oflaser spectroscopy it has been possible to determine not
only the value of the emissions from the stacks of roasting furnaces but also those
due to degassing processes from the roasted cinnabar banks. Of particular
interest is the determination of the emission values obtained from mining
structures that are still in activity or are in an abandoned state (Ferrara et al.
1998a, in press).
2
The Almaden District
2.1
Location
The Almaden district (Spain) is a world-scale exceptional case of mercury
metallogeny. Approximately one third of all the mercury consumed by man
during all his history has come from this district.
The mining area is located in the central part of the Iberian Peninsula, 300 km
south of Madrid (Fig. 2). The most important village in this area is Almaden,
with a current population of 9000.
The climate is semiarid and temperate, with an annual rainfall of 50 cm. Winds
blow predominantly from the west and southwest in the shallow valley where the
village is located.
The mercury deposits, described in detail by Ortega and Hernandez (1992),
have been mined without interruption over the past 2000 years. The three most
important mines are: Almaden, EI Entredicho (an open pit) and Las Cuevas, with
an overall average grade of 3.5% of mercury. The mercury mineralization consists
mainly of cinnabar, but contains also native mercury.
Production data indicate that the total production up to 1991 was 7.5 million
flasks, 7 million of which were produced solely from the Almaden mine. A
maximum annual production of 82000 flasks was reached in 1942; during the
past 20 years, average production has been about 40000 flasks per year.
The main mine, the ore-roasting furnaces, and the distillation plant are located
close to the village of Almaden; the main galleries run beneath it, and the outlets of
the ventilation systems are close to the houses. The roasted cinnabar banks (3700
000 tons of roasted ore, containing a mean percentage of mercury of 0.15%)
surround the mine complex and present an overall area of the order of 3 x 10 5 m 2 •
While extensive literature is available on the structure and genesis of mercury
deposits in the Almaden zone (Julivert et al. 1972; Saupe 1990), the only
prominent studies on mercury cycling and transport in the terrestrial and aquatic
systems are those performed by ORNL (Oak Ridge National Laboratory;
53
Only in the past few years has remote sensing LIDAR (light detection and
ranging) technique been applied to mercury detection (Edner et al. 1992, 1993,
1994; Ferrara et al. 1992). This has for the first time made possible a reliable
evaluation of mercury emissions from both point sources and extended ones.
With this technique oflaser spectroscopy it has been possible to determine not
only the value of the emissions from the stacks of roasting furnaces but also those
due to degassing processes from the roasted cinnabar banks. Of particular
interest is the determination of the emission values obtained from mining
structures that are still in activity or are in an abandoned state (Ferrara et al.
1998a, in press).
2
The Almaden District
2.1
Location
The Almaden district (Spain) is a world-scale exceptional case of mercury
metallogeny. Approximately one third of all the mercury consumed by man
during all his history has come from this district.
The mining area is located in the central part of the Iberian Peninsula, 300 km
south of Madrid (Fig. 2). The most important village in this area is Almaden,
with a current population of 9000.
The climate is semiarid and temperate, with an annual rainfall of 50 cm. Winds
blow predominantly from the west and southwest in the shallow valley where the
village is located.
The mercury deposits, described in detail by Ortega and Hernandez (1992),
have been mined without interruption over the past 2000 years. The three most
important mines are: Almaden, EI Entredicho (an open pit) and Las Cuevas, with
an overall average grade of 3.5% of mercury. The mercury mineralization consists
mainly of cinnabar, but contains also native mercury.
Production data indicate that the total production up to 1991 was 7.5 million
flasks, 7 million of which were produced solely from the Almaden mine. A
maximum annual production of 82000 flasks was reached in 1942; during the
past 20 years, average production has been about 40000 flasks per year.
The main mine, the ore-roasting furnaces, and the distillation plant are located
close to the village of Almaden; the main galleries run beneath it, and the outlets of
the ventilation systems are close to the houses. The roasted cinnabar banks (3700
000 tons of roasted ore, containing a mean percentage of mercury of 0.15%)
surround the mine complex and present an overall area of the order of 3 x 10 5 m 2 •
While extensive literature is available on the structure and genesis of mercury
deposits in the Almaden zone (Julivert et al. 1972; Saupe 1990), the only
prominent studies on mercury cycling and transport in the terrestrial and aquatic
systems are those performed by ORNL (Oak Ridge National Laboratory;