Drilling

COMPONENTS OF A TWIN METALS MINNESOTA DRILL SITE

WHY IS TWIN METALS MINNESOTA DRILLING?
Twin Metals’ drilling program gathers rock samples – known as “core samples” – that are studied to develop a profile, or three-dimensional picture, of the strategic metals deposits that have been identified for possible underground mining development. The core samples also provide information critical to engineering the future mine and developing customized mineral processing and environmental protection technologies. Drilling depths reach hundreds and thousands of feet below the surface, and samples are meticulously recorded and saved by the mining company and the state of Minnesota.

DRILL SITE

A drill site is a temporarily cleared area generally less than the size of a small homestead. Access to, clearing and reclamation of drill sites is generally regulated by state and/or federal governments, depending on land ownership. Some drill sites are regulated under seasonal restrictions. When drilling is completed, the drill site is “reclaimed” and allowed to return to natural habitat.

Below are examples of Twin Metals drill sites in the summer and winter seasons:

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DRILL RIG
Twin Metals partners with Virginia, Minn.-based IDEA Drilling to conduct its drilling program. IDEA utilizes modern mobile drill rigs that move site-to-site, reducing drilling time, noise and surface impacts. To date, the Twin Metals program has drilled more than 365 holes, with many holes serving as the starting point for multiple “angle holes” into a deposit.

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You can view a working drill rig here.

Additional images of Twin Metals Minnesota drill sites and drill rigs can be viewed here.

PROTECTIVE SWAMP MATSswamp-mats1
At many drill sites, large wooden platforms, known as swamp mats, are used underneath the mobile drill rigs to protect sensitive land surfaces during both drilling and the transportation of the rig. The use of these mats is a “best practice” in the industry that often exceeds state and federal requirements.

SUMP AREA
Yes, it can be ugly, but the small temporary sump area of a drill site servesSump-area
important environmental purposes. The
sump area is where water is stored for reuse in the drilling activity, greatly conserving water usage. The sump area also serves as a collection site for drill “cuttings,” the grey rock shavings (think “sawdust”) from the drilling. When the drill site is reclaimed to its natural state, the sump area is filled with its original material with no adverse impact on the environment. Reclamation of drill sites and sump areas are inspected by appropriate governing entities.

CASING EXTENSION
Tour-Overview_Casing-ExtensionA small diameter red pipe sticking up about five feet is the only lasting remnant of drilling activity at a drill site. This“casing extension” marks the drill hole for future identification and prevents surface water from entering the hole. Casing extensions remain in place for up to 10 years, after which the drill holes are permanently abandoned under Minnesota Department of Health (MDH) guidelines. Casing extensions are required and regulated by the MDH.

NEWLY RECLAIMED DRILL SITES
IMG_4713Drill sites are “reclaimed” to their natural state in accordance with state and federal requirements and industry best practices. Sump areas are filled in, the drill site is re-graded and downed timber can be scattered for decomposition. The areas are not re-seeded to avoid inadvertent introduction of invasive species. Native vegetation often emerges within weeks.

MATURE RECLAIMED DRILL SITES
OLYMPUS DIGITAL CAMERAMature reclaimed drill sites are often difficult to identify, but for the remaining casing extension. Mature reclamation is marked by a thick cover of grasses, berries, wild flowers and extensive sapling growth, providing excellent refreshed habitat for a variety of species.