Making ROCKWOOL insulation in Ranson

The making of our stone wool insulation: an overview of the manufacturing process 

Mineral wool or “stone wool” is a natural product made mostly from volcanic rocks. Natural rocks (such as basalt, dolomite and bauxite) may be supplemented with recycled mineral wool and slag from the steel industry. The stone wool manufacturing process consists of the following eight steps that ROCKWOOL has continued to refine over the course of our 80-year history. 

  1. Material Handling / Charging 
  2. Melting 
  3. Spinning 
  4. Wool Collection 
  5. Curing / Cooling 
  6. Cutting and Marking 
  7. Recycling Plant 
  8. Packing / Unit Load


Take a tour of our manufacturing facilities 

Watch the below video to see for yourself the operations and production of stone wool insulation within our advanced manufacturing production process. 

ROCKWOOL Ranson, Jefferson County, West Virginia final rendering of factory scheduled to open 2020

Advanced Manufacturing Factory Tour

We’re proud of the efficiency and productivity of our manufacturing facilities. They offer a unique combination of state-of-the-art technology and equipment, and people working together to ensure the highest product quality.

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Keep up-to-date on news and announcements, project information, and job postings from the ROCKWOOL development in Ranson, Jefferson County by subscribing to our Newsletter.

ROCKWOOL ensuring minimal noise around RAN5 factory for ranson, jefferson county, wv community

ROCKWOOL is taking precautions to ensure minimal noise around the factory in the Ranson community.

Upholding visibility of the landscape  

Jefferson County offers unique landscapes that are a draw to residents and visitors alike. We take being a neighbor seriously and will be upholding stringent conditions regarding the opacity levels of the plume that comes from our stacks. To do this we are installing state-of-the-art abatement technology that will result in our operations being minimally visible, consisting mostly of evaporated water that will disappear rapidly.  

Given the nearby sensitive viewsheds including Antietam National Battlefield and Harper’s Ferry National Historical Park we partnered with both the West Virginia Division of Culture and History as well as the West Virginia Division of Air Quality to analyze any potential visual impairment due to our facility in Ranson, WV. 

The assessment confirmed that the ROCKWOOL facility will not have any adverse effects on these, or any other property identified by the National Register in the area (Farms: Hazelfield, Tackley, and Rellim Orchard). 

Environmental stewardship in Jefferson County

Our facility will have two primary stacks at a height of 213 feet each, the heights themselves being largely determined by the WV DEP and regulations for aviation safety along with dispersion requirements.

See for yourself how we're working hard to minimize our footprint.


Plume opacity with WESP on and off, showing near invisibility with this abatement technology.

You can see the factory. You can see what it looks like. It has stacks. But it doesn’t operate with any visible plume.

Managing truck traffic

ROCKWOOL relies on transportation from trucks to both deliver raw materials to the factory and for delivery of final products to distributors and retailers. 

Factory traffic will primarily occur Monday through Friday and we do not expect our truck traffic for the factory in Jefferson County to be a nuisance to our neighbors or the community. The total traffic, including employee vehicles, is expected to result in a two percent increase from existing traffic on WV-9. 

Our goal is to ensure the most direct access between the highway and the factory to reduce the impact on local traffic, particularly in relation to schools. From the Ranson site, trucks will leave Northport Avenue, turn left on old Route 9, going the opposite direction of North Jefferson Elementary School, and access the highway at Wiltshire (shown in the second visual below). 

We will keep the public informed if there are any changes to this estimate as the project moves forward. For more information, download our Truck Traffic Fact Sheet.

Creating a safe and environmentally-friendly operation

Production at our 130-acre site in the City of Ranson is slated to begin early 2021, and once up and running, we will be producing stone wool insulation for residential, commercial and industrial uses. 

Stepping inside our manufacturing facilities, witness a modern and efficient operation that combines state-of-the-art equipment with people, working together to ensure the highest levels of product quality. The assessment of our operating environment includes an overview of health and safety practices, water usage and treatment, our emergency preparedness, and concludes with a plant tour video. 

Health and safety practices

Besides delivering solutions that protect our customers, ROCKWOOL is also committed to providing a safe, fair, and engaging workplace for our employees. We have developed a culture that puts the safety of our colleagues first, including requiring all personnel to wear standard Personal Protective Equipment (PPE). Specific areas of the industrial facility require hearing protection, and some tasks may require additional safety gear that we provide. 

Our indoor air quality does not require employees to wear respirators or dust masks in their regular duties. Specific tasks requiring confined space entry are subject to Occupational Safety and Health Administration (OSHA) regulations and appropriate PPE is provided and used as required along with ensuring regular inspections of all company equipment. 

Video thumb RockWorld, Jens Birgersson, CEO

Safety at ROCKWOOL Group

Get more information about the importance of safety at our organization from CEO Jens Birgersson.

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Keep up-to-date on news and announcements, project information, and job postings from the ROCKWOOL development in Ranson, Jefferson County by subscribing to our Newsletter.


Water usage and treatment 

At our Ranson facility, we are implementing a closed-loop system where rainwater will be collected in two secure on-site ponds and used as the primary source of water in the production process.

In cases when rainwater is not sufficient, we will draw water supplied by Jefferson Utilities, Inc. which will provide water services to the facility. Our total water consumption will not exceed 125,000 gallons per day.

We will be installing a reverse osmosis (RO) system at the factory as standard water treatment equipment. The RO is used to ensure the needed water quality for our production process by limiting deposits and corrosion.

In addition, the Ranson facility will use a water softening plant to remove calcium and magnesium from the water, among other common minerals. This is done to ensure the longevity of the production equipment by limiting deposits (scaling) and corrosion.

As with RO reject water, wastewater from the softening plant has concentrated levels of total dissolved solids and salts. 

Get the full story

Learn more about water inflow, usage and outflow in the production process on our environment page including how we eliminate production water discharge to municipal sewer systems.

Take me there

Microsite Sizing: Ranson, West Virginia factory waterline and sewer line system diagram including all inflow and outflow of water from the facility. Includes details about the water in the closed-loop production process - water supply, stormwater collection pond. production water reuse pond.

ROCKWOOL Ranson, WV factory water system diagram shows an overview of the water and sewer line infrastructure supporting the closed-loop production process.

Prepared in the event of an emergency

At ROCKWOOL, we take all available precautions to prevent an emergency. As part of our emergency preparedness planning, we have conducted a risk assessment that includes risks associated with fire, explosion, and spills. This detailed risk assessment has concluded that no event on-site will cause any evacuation situation for schools and neighbors.

We have also completed hazard mitigation planning to ensure that once up and running, the facility will be fully compliant with a Spill Prevention and Recovery Plan (SPRP) and a Spill Prevention Control and Countermeasures (SPCC) Plan.

Members of the local team are also required to meet rigorous internal controls, which include regular drills carried out in partnership with local fire departments. These drills ensure that the emergency preparedness plans we have put in place can be executed should an event occur. 


1EPA, Workbook for Plume Visual Impact Screening and Analysis (Revised), EPA-454/R-92-023, 1992.

2Reference: County-Wide Groundwater Assessment, Jefferson County, West Virginia, Analytical Sciences Inc for Jefferson County Commission, April 2012

ROCKWOOL officials have been in contact with us and are offering any help, training, or information that will benefit us in mitigating any type of incident at the facility. We have been pleased with the proactive nature of ROCKWOOL officials in offering their help to us as we learn about the new technology on which they have based their processes... The potential of a minor or major incident regarding ROCKWOOL is no different than any other home or facility across the region.

Ross L. Morgan and Marshall DeMeritt

Fire Chief and EMS Chief
See the fire chief’s full statement