Dept. of Geology, University of Alaska, Anchorage, USA

Mac Robertson Scholarship Award Report

Keith Torrance

Department of Civil Engineering

University of Strathclyde, Glasgow.

July 2011 – December, 2011

Biography

I am a mature post-graduate student, in the

second year of a PhD in the Department of Civil

Engineering at the University of Strathclyde. My

undergraduate degree was in Geology from the

University of Glasgow in 1982 and I worked in

the mining and metals industry before returning

to Strathclyde to complete a master’s degree in

Geo-environmental engineering in 2008.

My research field is in environmental

geochemistry. I am investigating arsenic

speciation within water systems polluted by

mining and how the presence of other toxic

metals impacts remediation efforts. I was

awarded a Mac Robertson Scholarship in 2010

for £2,500 to support fieldwork at some

historical mining sites in Alaska and Oregon.

Figure 1. At Exit Glacier, Seward, Alaska.

My Research

Historical mining activities in Alaska have been very damaging to the environment; with most sites have

had little or no remediation. Metals, such as copper, zinc and lead are found as sulphide ores, or, like

gold, in close association with iron pyrites. Tailings discarded around the mine sites contain high large

amounts of waste sulphide minerals, which oxidise upon exposure to air to produce sulphuric acid run-

off which pollutes local streams and watersheds. Low pH enables many toxic trace metals, such as

arsenic, cadmium and antimony to become mobile and impact water quality in the vicinity of the mine.

My research is focused on the mobility of

arsenic, which are a common constituent of

metallic ores and a pollutant of particular

concern in drinking water. Arsenic exists in two

valence states, As(III) and As(V), which control

its behaviour in the environment and its toxicity.

I am investigating how the presence of other

toxic metals, such as Sb and Cr, affects arsenic

speciation and how this can be used to modify

remediation strategies in mine waters containing

two or more toxic metals.

While there are historical mining sites in the

United Kingdom, most metalliferous mines have

been closed since the end of the 19th century.

Alaska is a unique environment for study,

because it still has an active mining industry and

thousands of abandoned gold and mercury

mines.

Figure 2. Lucky Shot Mine.

Figure 3. Study Sites in Alaska and Oregon.

Trip Details

Field work in Alaska can be very challenging.

Most of the sites that I planned to study are in

remote areas that can only be accessed by air

and require considerable advance logistical

planning. Consequently, field work is much more

expensive than in Europe and would not have

been possible without assistance from the

MacRobertson fund. I travelled from Glasgow to

Anchorage in July 2010, where I was based out

of the University of Alaska, Anchorage (UAA)

and returned to Glasgow in December.

My visit was hosted by Dr. LeeAnn Munk, who is

head of the geology department at UAA and a

renowned geochemist. Dr. Munk has refined a

field arsenic speciation method, which avoids

the considerable difficulties in preserving arsenic

species. I was able to attend classes at the

university and utilise the analytical capabilities of

the geochemistry laboratory. Through LeeAnn’s

contacts, I was able to get permission to collect

samples at several mine sites and work

alongside crews doing environmental studies.

This included helicopter support to reach some

of the more remote sampling sites.

Figure 4. Helicopter attempting to land on a drilling platform at the Coleman adit, Hatcher Pass, Alaska.

My analytical results will be presented at the Society Economic Geology and Health (SEGH) conference in

Edge Hill, Lancaster in April. Most of the sites that I worked on had elevated levels of arsenic in water

exiting the mine adit and spoil heaps. One surprising outcome was that the mine water was has a much

higher content of the more toxic As(III) species that was predicted by chemical thermodynamics. I am

trying to relate to the underlying geology of the area to the water geochemistry.

Figure 5. Measuring water parameters at Shorty Creek.

While in Alaska, I made a side trip to Portland, Oregon to visit an abandoned mercury mine, Black Butte,

in southwestern Oregon and collect samples of water and soil. In addition to arsenic speciation

measurements, I am also plan to conduct mercury speciation determinations and attempt to model the

transportation of mercury from the site into the watershed of the river. Mercury has well known health

impacts and the main exposure route is through the consumption of fish with elevated levels of mercury.

Alaska is at the margin of the Pacific plate, as it is subducted below the North American plate and forms

a classic island arc, with active volcanoes forming the Aleutian island chain, several of which are visible

from Anchorage and have erupted in recent times. Earthquakes are common in the region and

subsidence from the massive 1964 earthquake that struck the Anchorage area has created a dead forest

zone around the Cook Inlet. I was able to visit and study some of the many glaciers in the region and

see first hand the impacts of climate change on glacier recession. It would be remiss not to mention the

abundant wildlife that I encountered, including moose, whales, bears and eagles.

While in Alaska, I participated in three academic conferences, including the Alaska Quicksilver Summit at

Girdwood. I presented some of the research that the department had conducted on mercury in the

environment. I made contact with scientists studying the impact of toxic metals in the environment in

Alaska, including the case managers responsible for remediation efforts at the Red Devil Mine, which I

plan to visit in 2011.

Scholarship Impact

The MacRobertson scholarship has impacted my research in a great number of positive ways. The

analytical data that I have collected will be invaluable in making comparisons with my other study sites

in the UK. It has given me the opportunity to work with a recognised expert in the field of geochemistry

and learn new methods that I will apply to my PhD research. Finally, it will help continue the relationship

with the Dept. of Civil and Engineering and the Dept. of Geology at UAA, Anchorage, which may give the

opportunity to students from both schools to do field work and study in our respective countries. I would

like to thank the trustees of the Mac Robertson scholarship for providing this opportunity.

Keith Torrance