The Elements of Innovation Discovered

Acid mine drainage to earth tone paints

Metal Tech News - February 8, 2024

Gamblin Artists Colors introduces oil paints pigmented with waste from acidic water draining from old coal mine.

Paints throughout the ages have been uniquely colored by crushed gemstones, rare shellfish, and even powdered Egyptian mummies. With that same pioneering spirit, the Portland, Oregon-based Gamblin Artists Colors began recycling dry pigment dust collected by their Torit air filtration system during the 1990s and mixing it into a paint color they called Torrit Grey. They have since expanded their Reclaimed Color offerings to include a collector's edition set of three earth tones: Rust Red, Iron Violet, and Brown Ochre. This time, the source is a defunct coal mine in Appalachian Ohio.

Ochre is one of the first paint ingredients used by early humans in cave art, such as body paint and pottery. It's a warm, natural pigment of earth, a mixture of ferric oxide and varying amounts of clay.

Thousands of years later, during the Industrial Revolution, America's appetite for coal and metals resulted in over 48,500 mines now long abandoned and improperly sealed. As years of rain seeped underground, toxic levels of heavy metals and acidity flowed back into waterways, where the metals oxidized into a slurry, commonly called acid mine drainage (AMD).

Artist John Sabraw, engineer Guy Riefler, and environmentalist Michelle Shively MacIver have spent over a decade collaborating with students at Russ College of Engineering and Ohio's College of Art + Design to develop a sustainable solution to rehabilitate the environment impacted by these metal-laden acidic waters flowing from legacy mines and making something useful in the process.

Their process begins with collecting tanks of AMD-impacted water from an Ohio stream. To neutralize the acidity, a base is added, then oxygen, causing the dissolved iron to crystalize and separate and settle at the bottom. The iron oxides are then dried into lightfast artist pigment. The pigment is heated to various temperatures to achieve each color. The resulting clean water is then returned to the river.

Within a year of operations, the affected area exploded into life once more, happily contradicting a 1997 Ohio Environmental Protection Agency report which found that 13 miles of the waterway were "irretrievably damaged to the extent that no appreciable aquatic life can be supported."

Tributary triage

Truetown Discharge is the largest and most extreme AMD contamination site in Ohio, with a flow rate just short of 1,000 gallons every minute; dumping more than two million pounds of iron oxide every year into Sunday Creek, a tributary of the Hocking River in southeastern part of the state.

"The best estimate we have on this is that it will continue discharging for at least 600 to 800 years," said MacIver in an interview with Vox, now the director of project development at True Pigments LLC.

Gamblin Artists Colors

From left to right: John Sabraw, Michelle Shively MacIver, Guy Riefler

True Pigments was founded by Rural Action – a community development organization – to regenerate the environmental destruction of abandoned extractive industry sites into thriving environments and economies of the future.

The company aims to transform AMD into colorants for commercial products, from bricks to blush, and prove the model can be replicated. Rural Action works across 29 countries, collaborating with communities and local leadership on a range of ESG projects across rural Appalachian Ohio.

Approximately 200,000 metric tons of iron oxide are employed in the U.S. each year to color construction materials, industrial coatings, fertilizer, plastics, paper, cosmetics, and more. A disruptive waste recovery pigment industry – that also happens to rehabilitate the environment – might secure a foothold with enough awareness and demand.

Scaling up

In 2018, Gamblin officially joined the multidisciplinary team, manufacturing the first batch of oil paint with pigment reclaimed from AMD.

To scale the project, the group took the campaign to Kickstarter and used the first batch to incentivize patrons to pledge $100 or more to the project. The campaign exceeded its goal of $30,000 to fund building a pilot plant to refine the process and eventually build a full-scale facility that could treat 1 million gallons of AMD per day.

Interest abounded from around the world, while at home, the Ohio Department of Natural Resources came on board, helping to draw up a proposal for a multi-million-dollar plant that would produce over 5,000 lb of pigment every day. The grant was awarded, and in late 2019, Gamblin received its first pallet of Reclaimed Earth Pigments, enough to make 2,500 three-color paint sets.

The new, full-scale True Pigments treatment plant will have the capacity to produce over 5,000 lb of pigment every day while treating 1.4 million gallons of water.

While other companies harvest iron oxide using passive systems such as settling ponds to precipitate iron out of mine water, True Pigments' technology operates more like a wastewater treatment system – harvesting and treating large amounts of water quickly, with a much smaller footprint. The facility will create local job opportunities and aims to clean and restore seven miles of Sunday Creek.

"This is our home, our people, our community. The whole reason we spent 10 years creating this technology is to clean this stream," said MacIver. "Talking with investors is a lot of educational outreach. It's such a niche business. It's not a traditional pigment or wastewater treatment business. It's this weird thing no one else is doing right now for profit. That's been a learning curve."

Crews broke ground on the site in 2023. The facility is expected to come online as early as 2026, with an estimated $20 million in funding from the Ohio Department of Natural Resources, the Office of Surface Mining Reclamation and Enforcement, and private donors already in place.


Reader Comments(1)

Eidolon writes:

Cool story!

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