What techniques does Constantine use in mineral exploration?

Constantine employs a variety of exploration tools to aid in the exploration and discovery of additional mineralization at the Palmer property. Traditional methods such as prospecting and mapping are still very important, but we now use diamond drilling, geophysical surveys, and detailed geochemical analyses. Together, these techniques help us understand the three-dimensional surface and subsurface geology. Current work is focused on additional diamond drilling to expand known zones of mineralization and to discover new zones. Constantine also sponsored a Master’s thesis that helped us better understand the deposit.

Drilling is performed by helicopter portable drill rigs that are set on temporary wooden platforms. Drill bits embedded with diamonds cut and extract tubes of rock referred to as drill core. While actively drilling, water is continuously pumped down the hole to keep drill bits from overheating and to wash away cuttings. Drill water additives are often used to assist in hole stabilization and cutting removal. All activity has been supported by helicopter including the movement of drills and personnel. In 2014 Constantine plans to rehabilitate a portion of an existing mineral access road (originally built in the late 1970s) that will provide better access to our work sites, reduce helicopter flight time, and increase crew safety.

Geologist Examining Drill Core

Diamond Drilling

Diamond Drilling

Downhole Geophysical Surveys

Who works in mineral exploration?

Mineral exploration is a broad field that typically employs a diverse mix of employees including geologists, geotechnicians, diamond drillers, geophysicists, pad builders and carpenters, surveyors, helicopter pilots and mechanics, cooks, housekeepers, maintenance workers and general laborers, mountaineers, medics and first aid attendants, expediters, and others. The Constantine team consists of many of these positions, many of whom are Haines Borough residents. Services and supplies that support our exploration work include items such as locally sourced lumber, locally built drill core boxes and drill core racks, meals and accommodation, fuel, hardware, and office supplies.

What metals are found in the Palmer deposit?

Mainly copper and zinc, but also significant amounts of gold and silver. Information gathered mainly from the 2006-2009 drilling programs and some information from previous programs were used to calculate the initial resource estimate for the Palmer Property, which was released in January 2010. This study defined an inferred resource containing 4.12 million tonnes of rock with metal grades of 2.01% copper, 4.79% zinc, 0.30 grams/tonne gold, and 30.5 grams/tonne silver in the RW and South Wall Zones of the Property. Copper is vital to our modern society and is used extensively in energy generation and distribution, building products and electronic equipment. It is also a core constituent of many ‘green’ technologies, such as solar cells, wind turbines and electric vehicles. Zinc is primarily used in the construction and automobile industries for corrosion protection, but is also an essential micronutrient for human health.

The Mineral Information Institute has assembled a great website with information on mineral properties and their various uses:

Students and teachers might be interested in downloading this 40-page PDF book published by the United States Geological Survey (USGS) entitled The Life Cycle of a Mineral Deposit - A Teacher’s Guide for Hands-On Mineral Educational Activities.

What type of deposit is Palmer?

The Palmer Property is host to VMS-style base (copper, zinc) and precious (gold, silver) metal mineralization. VMS, short for volcanogenic massive sulphide, refers to a type of deposit that is generated by volcanic activity and is composed of sulphide minerals. Deposits are formed by hydrothermal venting of metal rich fluids on the seafloor, a process that is still found in modern oceans and can be seen in scientific videos of deep-sea “black smokers”. In the case of the Palmer VMS deposit, this process occurred over 200 million years ago on an ancient seafloor which has since been folded and uplifted to its present position in the mountain.

Sulphides are minerals whose chemical composition includes sulphur in the compound. Sulphides are common in most rocks; however in mineral deposits they occur in sufficiently high concentrations so as to be economic to mine. In the Palmer deposit, these minerals are mainly chalcopyrite (copper), pyrite (iron), and sphalerite (zinc). The deposit also includes a significant amount of barite, a barium sulphate. Sulphide minerals form the ore in most types of mineral deposits, and are the primary source of copper, zinc and lead used in the world today. Please explore the Palmer Project section of the website for more geological and technical details.

Will the Palmer Project become a mine?

We don’t yet know the answer to this question. Constantine has been able to define a considerable new mineral resource, but it is still far too early to predict if or when there could be an operating mine at the Palmer Property. There are four main stages of mineral exploration & development, starting with an early “grass-roots” exploration stage (Stage 1) where a property may have one or more mineral occurrences or showings, but no established mineral deposits. The Palmer Property was considered an early-stage project from 1969 until 2007 when drilling encountered thick intervals of significant mineralization. It would now be considered a mid-stage project (Stage 2) where we are required to do further exploration in order to enlarge and better define the existing inferred resource. Most of the work at this stage involves drilling in an attempt to expand the size of the deposit and to determine the grade and quality of mineralization. It takes considerably more work and time after that to complete the engineering evaluations, economic assessments, and environmental studies that are necessary to determine the feasibility of mine development (Stage 3). If a project is determined to be both economically and environmentally feasible to develop, it then takes more time still to permit, finance and ultimately construct (Stage 4).

If the Palmer Project becomes a mine would it be an underground or open pit mine?

The high-grade nature of this kind of deposit allows for underground mining. The advantage of a high-grade underground mine is the rate of mining is much lower than that of an open pit mine and much less material is actually mined. It also allows miners to be much more selective in what is removed, thereby producing far less waste rock than other types of mines. The result is a mining operation with a much smaller surface disturbance and lower total footprint.

How is ore, like that found at Palmer, typically processed?

Ore is crushed and ground (milled) to the size of the individual mineral grains. The minerals containing the metals of value are then separated from those that are waste, resulting in what’s called a mineral concentrate. The concentrate is then transported to a smelting facility where the metal is extracted from the ore minerals and further refined. Smelters all over the world process concentrates from North American mines and, accordingly, it is beneficial to be near a deep-sea port, like Haines, that allows concentrate to be shipped efficiently.

Would a mine at Palmer produce tailings?

Yes. Almost all metal mines produce tailings. Tailings are the finely ground sand size particles of rock that are left behind after milling the ore and extracting the minerals of value. It is far too early to say what the best option for tailings storage would be, but some common options include (a) dry stack storage in which a dense and stable material is ultimately covered and reclaimed with vegetation (b) placement back underground as paste-fill, and (c) impoundment or ponds in which the tailings are kept under water to avoid oxidation. Rock characterization and metallurgical studies will guide a plan to ultimately design an environmentally responsible tailings and rock dump facility that is protective of the surrounding ecosystem.

What is Acid Rock Drainage and would a mine at Palmer generate it?

Sulphide minerals when left exposed to oxygen will breakdown to their constituent elements and have the potential to generate acid and liberate metals (acid rock drainage or ARD). This process, which requires both oxygen and water similar to the way rust forms on a car, is naturally occurring and is enhanced by increasing the mineral surface area that is exposed to air when breaking and milling rock. Historically acid rock drainage has resulted in negative environmental impacts at some mines; fortunately, we now benefit from decades of research and science into ARD and modern mines are designed and strictly regulated to ensure ARD and the negative impacts associated with it do not occur. The design starts with characterizing your rock types prior to mine design to minimize the amount of development rock that requires special handling. At the Palmer project, while there are sulphide minerals present, there is also a significant volume of acid neutralizing carbonate rich rocks within and surrounding the deposit, which provide flexibility and extra protection in the environmental design of a mining operation.

What scale of operation could Palmer become?

It is too early to know if there will become a mine and accurately predict mine production rates. But based on what we know so far, and on comparison with other similar deposits such as the Greens Creek mine on Admiralty Island and Myra Falls mine on Vancouver Island, BC it is not unreasonable to envisage a 1500 to 3500 ton per day underground mine with the potential to operate sustainably for many decades. The envisioned underground mining rate is significantly less than that at many open pit mines operating in North America that process 25,000 to >100,000 tons of ore per day and in addition also move significantly more waste rock.

Who could work at a future mine?

Mining is similar yet very different from mineral exploration and this is reflected in the different mix of employees. Mining is a highly technical operation focused on extracting the ore in the most efficient, safe, and environmentally conscious manner. Active mining operations employ miners, heavy and light duty equipment operators and mechanics, engineers, geologists, metallurgists, lab technicians, environmental scientists, and drillers, together with a large support team of electricians, carpenters, office managers, accountants, health and safety specialists, medics, warehouse staff, janitors, truck drivers, and cooks…to name a few. One would expect significant participation from Haines Borough residents in any mining operations, both directly and indirectly. Should Palmer eventually advance to a mine, potential operations would likely include between 150 to 300 direct long term jobs. Goods, services, and taxes are a significant part of the operation’s revenue that is distributed to the State and the community.

The Alaska Miners Association also publishes annual reports summarizing the economic benefits of Alaska’s mining industry.

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