By Karen Edelstein, NY Program Coordinator, FracTracker Alliance

In the Finger Lakes Region of New York State, while the debate rages about underground storage of gas in abandoned salt solution mines near Seneca Lake, the story is quite different to the east at Cayuga Lake. Cayuga has a history of not just solution brine mining, but also extensive mining of solid rock salt. The map below shows the footprint of underground salt mining – room-and-pillar style 2300 feet below Cayuga Lake – by the multinational corporation, Cargill. Mineral rights beneath the lake are owned by New York State, but note that some of the mine also extends underneath privately owned land in the Town of Lansing.

Map of Lansing, NY Cargill Salt Mine. For a full-screen version of this map (including map legend), click here.

About this Map

The interactive map (above) shows the location and extent of the Cargill Salt mine in Lansing, NY. The boundaries of the mine were digitized from a map, Figure 2.3-2, entitled “Plan View of the Cayuga Mine Showing East and West Shoreline Benchmark Locations” from the Spectra Environmental Group, Latham, NY, circa 2004, and another planning document acquired. Here is one of the original maps, and a planning map showing expansion through 2003. An additional map from a Cargill mine expansion permit request, viewed at the DEC headquarters in Cortland, NY, shows additional requested development under residential areas in Lansing. This layer is shaded green.

Questions Abound

The dynamics around salt extraction, and other uses such as gas extraction, raise several questions.

Consider the stratigraphic column of rocks in New York State. The salt layer that is being mined by Cargill is the Salina Group, approximately 2300 feet below the surface. Salt is dug out mechanically, broken up by machinery and explosives to break up the solid layer. The Marcellus Shale (in Lansing) is above that salt layer–in the expanse of Middle Devonian Rocks, while the Utica Shale is below it–part of the Ordovician rock strata. In order to drill into the Marcellus Shale, one would not need to enter the salt layer, although the boundary of rock between the two strata might only be a few hundred feet thick. Reaching the Utica Shale would require piercing the salt layer. The Central New York region is crisscrossed by an abundance of vertical cracks and joints in the bedrock, some of which are thought to be hundreds to thousands of feet long, and may extend to “basement rock”, the ancient rock below the hundreds-of-millions year-old sedimentary layers such as the shale, sandstone, and salt.

Numerous plugged and abandoned salt wells from the days of solution mining–mid 1800s to mid 1900s– are located on and near Salt Point, the delta where Salmon Creek meets Cayuga Lake. As the map shows, the rock salt mining extent is near to, but not in contact with, these old brine wells. The underground shape of the solution wells is not entirely understood, and may be variable due to different rates of dissolution of halite during the extraction process. The rock salt is mined out as a solid, not a a saturated salt liquid that would have then gone through an evaporation process in a giant kiln. Were rock salt extraction to occur too close to the old solution wells and a wall breached, flooding in the current Cargill mine could result.

This would obviously not be good.

(Nor, for that matter, would have been the prospect of storing spent nuclear fuel in the abandoned brine wells, something that was being considered in the mid-1970s. In a 3-volume study of the geology of the Salina Basin (spanning a d-state area), the conclusion made by the Stone and Webster Engineering Corporation¹,  consultant to the US Department of Energy, was that no salt mining sites in the Finger Lakes region were appropriate  for nuclear fuel storage without further study of the area’s extensive, but under-studied, faulting patterns.)

What are the implications of other sorts of mineral extraction, in this part of the Finger Lakes Region?

Yours or Mine?

The extent of Cargill’s mining under residential portions of the Town of Lansing provokes several questions. For example, if Cargill has long-term access to these subsurface mineral rights, property owners do not control the land beneath their homes. This is not altogether uncommon in areas of mineral – or oil and gas – extraction. Can that land be leased for gas drilling?

It was revealing to look more closely at records of expired oil and gas leases in the area. During this process, we discovered that within the area that is “claimed” by Cargill for subsurface mineral extraction, numerous surface owners had also leased the gas rights beneath their property (see blue starburst markers on the map)², even if the property deeds explicitly, for example,  indicated that the property owner “will not cause any damage to the said salt or mining operations [of the party of the second part] by permitting or consenting to any other drilling 1000 feet below the the surface of said premises, for oil, gas, water or any other substance or mineral..” (Tompkins County Clerk, Liber 463, p.284-5).  Here are links to page 2 and 3 of the deed, and the very comprehensive leasing clause of one of these oil and gas leases that permits a wide variety of gas-extraction related activity–both on the surface, and below ground.

Four of the ten leases were on property held by the Town of Lansing itself, and one other was on property owned by a local elected official. While all of these leases expired in 2012, and were never, in fact, drilled (due to the de facto moratorium on HVHF gas extraction in New York), the mash-up of these datasets raises important questions about our permitting structure. The implications of two separate entities claiming overlapping subsurface rights spotlights many questions regarding the oversight and regulation of potentially conflicting uses. Of particular concern are the risks posed by migration of gas through joints and fissures in the bedrock that are further weakened by hydraulic fracturing – and the potential for methane explosions³ in salt mines, whether or not a well shaft penetrates the salt gallery.

For more details on operations at Cargill’s Lansing mine, see this article from The Lansing Star, September 2012: Lansing Down Under: A Look at the Cargill Salt Mine.

References

1. Regional Geology of the Salina Basin, Report of the Geologic Project Manager
   Volumes 1 and 2, Phase I, August 1977-January 1978, and Volume 3 Update, October 1979. Prepared by Stone and Webster Engineering Corporation for the Office of Nuclear Waste Isolation, Battelle Memorial Institute, Project Management Division, US Department of Energy.
2. Map of Gas Leases in Tompkins County
3. Cargill Incorporated Belle Isle Salt Mine Explosion (1979)