Mining and Quarrying - Frequently Asked Questions

For related questions, go to Mineral Collecting - Frequently Asked Questions.


Q1. Is there any current mining or quarrying activity in Maine?     Back

While there are no metallic mineral mines currently in production, other geologic natural resources are being excavated at many places across Maine. According to the U.S. Geological Survey, the estimated value of mineral production for Maine in 2008 (PDF format) was $158 million.


Q2. What are the primary products of Maine's mines and quarries?     Back

The principal resources being extracted from the ground in Maine today are sand, gravel, and crushed stone, referred to collectively as "aggregate." Granite and slate production continues at a steady rate, now used more for specialty products than for building construction. Irregular, rough fieldstone or "flat rock" that is used for landscaping projects, may be extracted from glacial deposits or, increasingly, from shallow quarries. The long-stable lime industry continues to be an important part of the Thomaston-Rockland area economy, with large reserves remaining. Gemstones, both for supplying the jewelry industry and for private collectors, are still being produced by several small operators in southwestern Maine.


Q3. Are there State laws and regulations controlling excavation, mining, and quarrying?     Back

Yes. In addition to the general land-use regulations restricting activities that impact such areas as wetlands, beaches, dunes, water bodies, significant wildlife habitat, or other environmentally sensitive areas, there are specific Maine statutes and rules about excavation, mining, and quarrying. Details and links to further information can be found through the Mining page of the Maine Department of Environmental Protection, and Land Use Standards (Chapter 10) of the Land Use Planning Commission.


Q4. What is "aggregate"?     Back

In the minerals industry, aggregate (PDF format) refers to a bulk material made up of individual particles or fragments. Sand and gravel and crushed stone are the most common aggregate materials in Maine. In recent years, sand and gravel have accounted for about 70% of aggregate production statewide, with crushed stone accounting for the remaining 30%. Aggregate is used for many construction purposes, including road and building foundations, fill, surface drainage systems, and asphalt road surface material.


Q5. Do gravel pits need to be registered with the Department of Environmental Protection (DEP)?     Back

Well, it depends. Current regulations require "borrow" pits with 5 acres or more of active area to be registered (with a few exceptions). Smaller excavations for sand, gravel, or fill, or inactive pits generally do not need to be officially registered with the State. But excavations less than 5 acres in size for clay, topsoil or silt must be operated in accordance with certain standards to ensure environmental protection. For a general description of the registration system for gravel pits and similar surface excavations, see the Issue Profile at the DEP web site. For more complete information, including a map of mine sites currently licensed by the DEP, see the links on the DEP's Mining Page. Keep in mind that DEP regulations do not apply in unorganized townships, which are under the jurisdiction of the Land Use Planning Commission, and that local ordinances may have additional, more stringent requirements.


Q6. Where can economic sand and gravel deposits be found?     Back

Much of the sand and gravel used for construction purposes in Maine was deposited by water melted from glaciers. If possible, water runs downhill so most gravel deposits are found in valleys and other lowlands where they were laid down in glacial outwash streams, glacial lakes, or the ocean. Ice-tunnel deposits (eskers) are notable exceptions. Some of these ridges of sand and gravel, deposited in confined subglacial tunnels, climb up hillsides and pass through elevated gaps in the hills. Surficial geologic maps are a useful guide to where geologists have found sand and gravel resources on land.

Sand and gravel deposits are also present on the coast, in Maine's beach and dune systems, and offshore on the sea floor. Due to significant environmental restrictions or logistical constraints these are not economically available resources.


Q7. Do valuable gems occur in Maine?     Back

Precious gems such as diamonds, rubies, and emeralds are not native to Maine, but some very good semi-precious gemstones have been found here. They include the gem varieties of quartz (colorless, rose, smoky, and amethyst), beryl (as blue aquamarine and pink morganite), and tourmaline (pink, green, blue, and multicolored). Deep red garnet crystals sometimes contain clear areas that are suitable for faceting, but usually yield only very small gems.

Tourmaline is the official State Mineral of Maine, and the most valuable and highly sought-after gem material that can be found here. Gem tourmaline has been mined in Maine since the 1820's, and the oldest location (Mt. Mica in Paris Hill) is still producing today. Tourmaline is actually a group of minerals having various colors and compositions. The black iron-rich schorl is most common in Maine. It may form sharp crystals but is not a suitable gem material. The species called "elbaite" is very colorful, but only a small percentage has the desired transparency for gem cutting. Many jewelry stores sell tourmaline from other parts of the world besides Maine, so you may want to get a written guarantee of the source if you want only authentic Maine tourmaline. See the Tourmaline Fact Sheet for more information on this mineral.


Q8. What government agencies enforce regulation of metallic mineral exploration and mining in Maine?     Back

In those areas of Maine which are in organized towns and cities, the primary responsibility for enforcing environmental regulations rests with the Department of Environmental Protection (DEP), as administered through their rules (see Chapter 200 of DEP rules). In the Unorganized Territory of Maine (UT), both the DEP and the Land Use Planning Commission (the LUPC) have administrative roles. The responsibilities of the two agencies with respect to metallic mineral mining are changing, because of a State Law passed in 2012 (Public Law 2011, Chapter 653). This law will take effect incrementally, through rulemaking by the LUPC and the DEP in 2013 and 2014, until the new statute, the Maine Metallic Mineral Mining Act, takes effect on June 1, 2014. [See statute 38 MRSA §490-LL et seq.] The major change in the roles of the two agencies is that the LUPC will be responsible only for setting land use standards and for deciding through land use zoning where mining will be an allowed use, and the DEP will have sole responsibility for environmental regulation, permitting, and enforcement. Until the new rules are in place, the LUPC and DEP will continue to have shared responsibility as specified under the existing rules. The DEP Chapter 200 rulemaking process is described here and the LUPC Chapter 12 rulemaking process is described here.

For those State-owned lands where mining is allowed, the Maine Geological Survey and the Bureau of Parks and Lands share responsibility for making rules about exploration and mining activity.

In addition to State regulations, there may be more restrictive local ordinances related to mining. Those ordinances would be administered by the city or town government.


Q9. Do I need permission of the landowner to look for mineral deposits?     Back

Yes. All the rules of land access and trespassing apply to prospectors and mineral collectors as they do to anyone else. There are no special privileges afforded to people doing mineral exploration work. In the particular case of looking for minerals on State-owned land, an exploration permit is required from the Maine Geological Survey. For private land, agreements must be reached with the landowners and owners of the mineral rights, if they are held separately. Any person conducting mineral exploration where the total exploration expenses incurred in a calendar year exceed $25,000 on private, leased or otherwise acquired lands within Maine must register with the director of the Maine Geological Survey.


Q10. If I discover a mineral deposit does it belong to me?     Back

Only if it is on property you own, or if you have obtained specific legal mineral rights given to you by the landowner. Ordinarily, a Maine landowner owns the land from the surface on down, unless the mineral rights have been intentionally separated from the surface ownership by legal agreement. Someone interested in mineral exploration would expect to execute a lease agreement with the landowner or the owner of the mineral rights before beginning exploration activity, in case anything of value should be discovered.


Q11. Does Maine allow mining in State Parks and other State-owned land?     Back

Mining is strictly prohibited in all Maine State Parks. There are other state-owned lands, however, including submerged lands, in which exploration for mineral deposits and mining are not prohibited. These activities are limited and regulated by Statute (Title 12, Chapter 201-A, Subchapter 3). A paper copy of Mining on State Lands statutes may be requested free of charge from the Maine Geological Survey (contact us).


Last updated on February 21, 2013