Tag Archives: mining

Bull’s Liver

Defined: An inorganic silt of slight plasticity; quakes like jelly from vibration.

Bull’s Liver is a highly unusual soil, with unconventional engineering behaviors. Without sufficient testing and identification, these soils can cause damage and delays in development projects, or result in construction cost overruns. To avoid such overruns, it is crucial that soil properties be sufficiently identified during subsurface exploration, and proper evaluations be considered during project design phases.

An informative video showing the extraordinarily unique behavior of this soil may be viewed at the IEC YouTube channel. Go go http://youtu.be/No16bDOTVi0.

Rock Flour (or Bull’s Liver) consists predominantly of silt-size particles, but has little or no plasticity. Non-plastic rock flour contains particles of quartz, ground to a very fine state by the abrasive action of glaciers. Terzaghi and Peck (1967) state that because of its fine particle size, this soil is often mistaken as clay.
In describing this soil, the term “bull’s liver” apparently comes from its in-situ appearance. It has been observed that in a saturated state, it quakes like jelly from shock or vibration and can even flow like a liquid (Sowers and Sowers, 1970). This is of course a highly undesirable condition, not only for construction work, but for permanent foundations.

Case History

Cortlandt Street Station, Manhattan, New York-Photo (C) MTA Bridges & Tunnels Special Archive. Used with permission.


The Cortlandt Street Station, which serves the R&W subway lines in Manhattan, New York, is located immediately adjacent to the World Trade Center site. Constructed in the early 20th century using cut-and-cover methods, the station has two platforms and twin tracks situated within a typical New York City Metropolitan Transit Authority (NYCMTA) concrete arch box structure. Soils in the area, known locally as “Bulls Liver,” soils are typically low-permeability, low-plasticity silts and have historically demonstrated high instability when saturated and subjected to construction-induced disturbance.
This was the case when recovery and construction activities at the adjacent World Trade Center site created significant ground loss and subsequent loosening of the surrounding soils at the station site, resulting in settlement of the station structure up to three inches at the point of maximum deflection.*

*source: More Trench

With such cautionary tales to go by, any construction project manager where such soils are suspected, would do well to heed the signs, and do a more thorough examination than might normally be called for. It is best to err on the side of caution, rather than proceed into circumstances that place life and property at risk.

Using foresight now, to navigate the issues that will be crucial to you tomorrow – this is the ongoing philosophy of Impact Environmental. All our clients have their concerns about future value and liability. Your values matter to us, and our values demand that we work hard to eliminate your concerns. Call us now at 631-269-8800. Welcome to Solid Ground.

Mitigating the Risk of Asbestos Rock

Serpentine – A Naturally-Occurring Asbestos Rock.

“If we find 1 percent asbestos in building materials, we tear the building apart and take all kinds of precautions.” says Robert Reynolds, head of the Lake County Air Quality Management District, California. “We should do the same for rock with 1 percent asbestos.” In 1992, Lake County enacted tough regulations for handling chrysotile deposits in the subsurface where disturbance occurs. Companies proposing a construction project, roadbed or quarry on rock containing 1 percent asbestos or more must submit an extensive plan for protecting the health of workers and the community. Dust must be kept so low that it is not visible. Workers must be notified, and precautions are taken so that asbestos is not tracked off site on truck tires.

“There have been too many legal decisions and too many scientific studies for us to continue to breathe this in.” Reynolds says. “We can’t ban it, but we can make sure people are not exposed unnecessarily.”[1]

What It Is

Rock composed primarily of serpentine minerals is called serpentinite. Serpentines find use in industry for a number of purposes, such as railway ballasts and building materials, and find use as thermal and electrical insulation. When serpentine is excavated, or used as a road surface, the asbestos content can be released to the air, and this has caused concern over a long term health hazard from wind-borne dust.

Naturally Occuring Asbestos (NOA) occurs in rocks and soil as a result of natural geological processes. Natural weathering and human activities may disturb NOA-bearing rock or soil and release mineral fibers into the air, which pose a greater potential for human exposure by inhalation. [2]

A California Controversy

There are many known locations of Serpentine rock throughout the New York Metro area (home to Impact Environmental), so it is important that our clients take note of events in California, if only to establish precautionary protocols where NOAs exist. Back in 1965 the California Legislature designated Serpentine (the mineral) as “the official State Rock and lithologic emblem.” But recent controversy regarding the health hazards associated with Naturally-Occurring Asbestos Rock (NOA) created enough concern that in May of 2010, State Senator Gloria J. Romero proposed legislation (SB 624) to removed serpentine as the state rock. With no conclusive evidence regarding the real threat to health posed by the rock itself, any reference to health threats was stricken from the legislation as it was first proposed. For instance, the Act originally held the following language:

“SECTION 1. …(b) Serpentine contains the deadly mineral chrysotile asbestos, a known carcinogen, exposure to which increases the risk of the cancer mesothelioma. (c) California has the highest rate of mesothelioma deaths in the nation. (d) California should not designate a rock known to be toxic to the health of its residents as the state’s official rock. (e) It is the intent of the Legislature to remove serpentine as the State Rock.”

This section was simplified to:

“SECTION 1.  It is the intent of the Legislature to remove serpentine as the State Rock and lithologic emblem.”

This non-committal wording is emblematic of the issue surrounding NOA, i.e. the jury is still out on the real hazards of the rock in its native state (and on the legislation itself), but the documented hazards of asbestos as it has been used in the marketplace raises enough red flags so those concerned with occupational health must take note. For those responsible for the health and safety of employees exposed to this material – in excavation, construction or other tasks – an ignorance of this issue could someday turn into a nightmare of liabilities in the future.

Bloggers and Writers Take Both Sides

Perhaps depending on whether they have direct experience with mesothelioma, writers have lined up on both sides of the hazardous versu nonhazardous issue. In an article published by the NY TIMES –  “California May Drop Its Official State Rock” By Jennifer Steinhauer, July 13, 2010 – Malcolm Ross, a geologist who retired from the United States Geological Survey in 1995, said “There is no way anyone is going to get bothered by casual exposure to that kind of rock, unless they were breaking it up with a sledgehammer year after year.”

Nonetheless, KStarr of Fayetteville, NC, on July 14th, 2010 wrote:

“… I lost my stepfather to asbestos related cancer and all this bill is about is awareness – helping the public to understand that asbestos is a carcinogen and is highly dangerous. It’s not about whether anyone is going to take a sledgehammer to a serpentine rock. It’s about the SYMBOLIC meaning behind it. Good God – 10,000 people die from asbestos related diseases each year in the U.S. and CA has one of the highest rates of mesothelioma deaths (the deadliest of cancers). It is NOT from people going around smashing up rocks. It’s from INDUSTRY – mining sites, etc. where these people worked. Did you know that the rock was made the state rock in 1965 specifically because of the then “lucrative” asbestos industry – so how can geologists now say there is no link to asbestos? CA state geo and enviro groups now ALL agree that asbestos is dangerous and have issued numerous warnings about it. So what we’re really talking about here is removing a symbol that to people like me represents something tragic. And to the guy who said this is still being used to make jewelry – I hope you’re not in the room when that jewelry is being made. Seriously – how ignorant.”

Chrysotile Asbestos

In the IA/ADAO Chrysotile Asbestos Fact Sheet from The Environmental Information Association, the following may be found:

Fact #1: Asbestos is a regulated carcinogen.

Fact #2: There are 6 fibrous minerals that are currently regulated as “asbestos:”
chrysotile, amosite, crocidolite, tremolite, actinolite and anthophyllite
Fact #3: Chrysotile is the most common variety of asbestos found in products in the United States: It is the most abundant asbestos variety on earth.
Fact #4: Chrysotile asbestos has been a significant contributor to asbestos-related illness and death to the US and worldwide workforce.
Fact #5: There is sufficient evidence to conclude that ALL FORMS of asbestos, including chrysotile, are carcinogenic and are responsible for asbestos-related lung cancer, mesothelioma, laryngeal and ovarian cancer

California’s Response

In California as a whole, there are already strong requirements in place for construction and grading projects. Full text for the following excerpted “Final Regulation Order, Asbestos Airborne Toxic Control Measure for Construction, Grading, Quarrying, and Surface Mining Operations”, may be downloaded by accessing the California Air Resources Board’s Internet web page at http://www.arb.ca.gov/toxics/atcm/asb2atcm.htm.

New Jersey

More locally, in New Jersey, the transportation of Asbestos and Asbestos Containing Material (ACM) is a regulated activity. The transportation of asbestos and ACM must be handled in accordance with N.J.A.C. 7:26-3.5(d) and other guidelines including:

  • Registered New Jersey solid waste vehicles are required for the transportation of ACM and any solid waste containing asbestos. All vehicles shall be designed to prevent any spillage or leakage or emissions.
  • There shall be no visible air emissions during loading, transporting, or unloading operations.

Locations Within The New York Metropolitan Area

The U.S. Geological Survey (USGS) has an ongoing project to map the locations of historical asbestos mines, former asbestos exploration prospects, and natural asbestos occurrences. For the New York Metro area, the USEPA mapping shows the following locations.*


* From 2005 US Geological Survey Report – Published by the USGS on July 1, 2005, this report contains a regional map and an associated database that includes 324 locations where naturally occurring asbestos has been historically identified in the Eastern United States.

USEPA Guidance on Approaches for Mitigating Exposures to NOA [3]

The USEPA has provided guidance through specific recommendations where NOA is of concern. The extracts below are pertinent. The following general approaches to mitigate inhalation exposures to NOA are aimed at reducing NOA releases from rock or soil into the air:

  • Leave NOA material in place and undisturbed
  • Cover or cap NOA material
  • Limit dust generating activities
  • Excavate and dispose of NOA material Depending on the situation, a combination of engineering controls, work practices, and institutional (administrative) controls may be needed to implement an approach and reduce potential exposures to NOA.

Selecting an approach depends on factors including:

  • Accessibility of NOA (ground surface vs. below ground surface)
  • Types of activities that disturb NOA (construction project vs. gardening)
  • Climate and weather conditions
  • Current and future land uses
  • Technical and administrative feasibility of the approach

Approaches for reducing NOA exposure are similar to practices used for asbestos containing materials in commercial applications.

Excavation, Grading, or Utility Work at Construction Projects

Wet road surfaces with water using trucks, hoses, or sprinklers. Wet piles of excavated material and cover them with tarps, plastic sheeting, or other items1 Continuously mist the work area. Install wind barriers around the work area. Clean or decontaminate equipment and vehicles to ensure that no equipment or workers track soil out of the work area (a gravel pad, tire shaker, or wheel wash system may be used to clear soil from vehicles). Wet the work area using a spray system attached directly to rock cutting or drilling equipment, such as a fine-mist sprayer or a variable-rate fogger nozzle (similar to those used in fire fighting). Excavate utility trenches to an adequate depth and backfill them with clean soil so that future repair work will not need excavation into potential NOA-containing materials. When transporting NOA-containing materials, avoid overloading trucks; keep the material below the top of each truck compartment and cover material with a tarp. Limit personnel and vehicle access to the work area. Identify NOA-containing areas with signs. Reduce driving speed. Reduce drilling or excavating speeds. Excavate during periods of calm or low winds.

Roads and Parking Areas (unpaved and gravel roads)

Cover roads with non-NOA-containing rock, chemical sealants or dust suppressants, chip seals, limestone aggregate, petroleum sealants, or asphalt cement paving. Wet road surfaces with water. Install windbreaks or berms. Reduce driving speed. Avoid dusty areas, especially in windy conditions.

Around Communities (playgrounds, ball fields, pathways, and gardens)

Cover areas of rock and soil with clean soil, rock, vegetation, or other material (see next section, General Considerations for Using Covers or Caps). Pave over unpaved walkways, driveways, or roadways containing NOA. Landscape areas with vegetation, such as NOA-tolerant plants, and add a layer of organic mulch or NOA-free soil. Water plants often until they are established to minimize erosion. Water garden areas before digging. Keep windows and doors closed on windy days and during periods when nearby rock or soil may be disturbed, such as during construction. Limit track-in by using entryway (door) mats, and wipe down pets before they enter buildings to reduce the amount of soil tracked indoors. Allow children to play in outdoor areas only if the area has a ground covering, such as wood chips, mulch, sand, pea gravel, grass, asphalt, shredded rubber, or rubber mats. Relocate outdoor activities to areas that do not contain NOA (walk, run, hike, and bike only on paved trails). Avoid dusty areas, especially in windy conditions.

Limiting Naturally Occurring Asbestos Exposure To Workers

Other guidance has been provided by those with the most profound experience of the consequences of asbestos exposure. For further information regarding the following extracts please visit: www.mesotheliomaweb.org/mesothelioma

Beyond the miners who are tasked with extracting asbestos from rock, a number of other workers may be at risk for exposure to asbestos. The job fields that are most at risk to environmental asbestos exposure include construction workers, excavators, lumberjacks, gravel pit operators, farmers and landscapers. Basically, any professional that works in and around asbestos-laden soil is a potentially at risk for exposure. Local health agencies will help you follow Occupational Safety and Health Administration (OSHA) regulations to determine if asbestos is a health risk in your work area. Based on the level of asbestos identified by OSHA, employees may be required to wear Personal Protective Equipment (PPE) such as respirators. Other steps that can be taken to reduce asbestos exposure to workers include:

  • Using wet methods when working with soil and asbestos-containing products
  • Avoiding the use of compressed air or leaf blowers for cleaning purposes
  • Avoiding eating, drinking and smoking in dusty areas
  • Limiting access of unnecessary visitors to the worksite
  • Showering and washing hair before leaving the worksite
  • Changing out of and leaving work clothes at the work site*

In summary, too much is now known about risks to those who live or work closely with serpentine (NOA) rock, to ignore the guidance provided by responsible agencies who are charged with the protection of public health. Any work where these risks occur, should include appropriate risk abatement measures, and local agencies should continue to reinforce local regulation that emphasizes the safety of the public and our work force.

Using foresight now, to navigate the issues that will be crucial to you tomorrow – this is the ongoing philosophy of Impact Environmental. All our clients are concerned with future value and liability. Your values matter to us, and our values demand that we work hard to eliminate your concern. Call us now at 631-269-8800. Welcome to Solid Ground.


[1] From the March 11-17, 1999 issue of metroactive news & issues, “Dust in the Wind” Copyright © Metro Publishing Inc.
[2] USEPA – “Naturally Occurring Asbestos: Approaches for Reducing Exposure” Office of Superfund Remediation EPA 542-F-08-001 and Technology Innovation March 2008 (5204P) www.epa.gov
[3] USEPA – “Naturally Occurring Asbestos: Approaches for Reducing Exposure” Office of Superfund Remediation EPA 542-F-08-001 and Technology Innovation March 2008 (5204P) www.epa.gov