Foundry Sand Reuse in New Mexico | Foundry Recycling Services

Planning to reuse spent foundry sand in New Mexico? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what NMED needs before the sand can be reused.

Key terms

Spent foundry sand

Foundries bond silica sand into molds and cores for casting metal. The sand is reused many times in the plant. Spent foundry sand is molding and core sand that can no longer make molds or cores.

Green sand and chemically bonded sand

Green sand is bonded with clay, usually bentonite, plus water and additives such as carbon. Chemically bonded sand uses resin binders. Most cores are chemically bonded. The binder system affects what the spent sand contains.

Beneficial reuse

Beneficial reuse puts a waste material to productive use instead of disposing of it. New Mexico’s solid waste rules use the term recycling: collecting, separating, processing, or reclaiming recyclable materials and returning them to use as raw materials or products. NMED regulates the facilities that do this work.

TCLP

The Toxicity Characteristic Leaching Procedure (EPA Method 1311) measures how much of certain contaminants can leach from a sample. It is one part of deciding whether a waste is hazardous.

What’s in your spent sand?

Spent sand carries what the casting process added: binder residue, metal fines, and burnt core material. The alloy matters most. Sand from iron, steel, and aluminum foundries is the most commonly reused. Sand from leaded brass and bronze foundries is often regulated as hazardous waste.

Keep each stream separate. Baghouse dust, shotblast fines, cupola slag, broken cores, and core room sweepings need their own evaluation. Mixing them into spent sand can change how the whole load is managed. Track the alloys cast, the binder system, and any process changes.

New Mexico’s solid waste rules

New Mexico’s solid waste rules are 20.9.2 through 20.9.10 NMAC. NMED’s Resource Recovery Bureau, formerly the Solid Waste Bureau, runs the program. The rules shape reuse in four ways.

Foundry waste in the definitions

20.9.2.7 NMAC defines industrial solid waste as solid waste from manufacturing or industrial processes that is not RCRA hazardous waste. Its list of source processes includes iron and steel manufacturing and nonferrous metals manufacturing and foundries.

The same section defines special waste. It includes industrial solid waste that, unless specially handled or disposed, may harm the environment or endanger public health or safety. Special waste has its own storage, testing, transport, and disposal rules in 20.9.8 NMAC. Ask NMED how it classifies your spent sand.

Recyclable materials

Recyclable materials are materials that would otherwise become solid waste and that can be processed and placed back into use as raw materials or products. Recyclable material in transit or in temporary storage is excluded from the definition of solid waste.

Recycling facilities

Under 20.9.3.27 NMAC, a recycling facility that accepts only source-separated recyclable materials must register with NMED. It files at least 30 days before operating, and every five years after that. It must update the registration for any material change in operations.

A recycling facility that also accepts solid waste with the recyclables needs a permit under 20.9.3.11 NMAC. So does a processing facility. Under 20.9.3.8 NMAC, anyone who builds, operates, modifies, or closes a solid waste facility must first get a permit.

Handling and disposal limits

Under 20.9.2.10 NMAC, no one may store, process, or dispose of solid waste except by means the NMED Secretary approves. Solid waste may be disposed of only at a facility that meets the rules. Haulers of solid waste or recyclable materials must deliver only to a permitted or registered facility (20.9.2.8 NMAC).

Under 20.9.8.8 NMAC, the generator of special waste must send it to a facility permitted to accept that special waste. The other option is treatment at a permitted facility so it is no longer special waste.

Working with NMED

Classification: ask NMED’s Resource Recovery Bureau whether your spent sand is special waste and how the proposed use fits the rules.
Who files: the owner or operator of the recycling or processing facility files the registration or permit application. Confirm the receiving facility holds one that covers spent foundry sand.
Registration content: the operating plan describes the origin, expected composition, and weight or volume of the materials, the process, capacity, and the expected disposition rate.
Term: registrations are valid for five years. Renewal applications are due at least 30 days before expiration.
Permitted facilities: applicants meet with the Permit Section before they apply. A public hearing is held on each complete application. Permits are valid for 20 years.
Special waste haulers: all haulers of special waste must register with NMED.
Manifests: each load of special waste that starts in or is disposed of in New Mexico travels with a manifest under 20.9.8.19 NMAC.

NMED Resource Recovery Bureau: (505) 827-0197. NMED Hazardous Waste Bureau: (505) 476-6000.

Hazardous waste determination

New Mexico adopts the federal hazardous waste rules by reference in 20.4.1 NMAC. It incorporates 40 CFR Parts 260 through 266, 268, 270, 273, and 279, as amended, with listed changes.

New Mexico omits 40 CFR 260.30 through 260.33. Federally, those sections allow non-waste determinations and variances from classification as a solid waste for some recycled materials. Report hazardous waste emergencies to NMED’s 24-hour line, (505) 827-9329.

Under 40 CFR 262.11, the foundry must decide whether its spent sand is hazardous:

Make the determination at the point of generation, before mixing or dilution. Repeat it if the waste may have changed.
Check whether the waste is excluded from the hazardous waste rules.
Check whether it matches a listed hazardous waste.
Check for hazardous characteristics, including toxicity. Use knowledge of the materials and process, testing, or both. Test when knowledge alone is not enough.

Small and large quantity generators must keep records supporting the determination for at least three years after the waste was last sent for treatment, storage, or disposal.

TCLP testing and limits

Tell the lab the alloys cast, the binder system, and which streams the sample includes. Use representative samples. Agree on the sampling plan with the lab, NMED, and the receiving site before collecting.

A waste is hazardous for toxicity if its TCLP extract meets or exceeds any limit in 40 CFR 261.24. The limits for the RCRA metals are:

TCLP regulatory levels, RCRA metals
Contaminant	EPA waste code	Limit (mg/L)
Arsenic	D004	5.0
Barium	D005	100.0
Cadmium	D006	1.0
Chromium	D007	5.0
Lead	D008	5.0
Mercury	D009	0.2
Selenium	D010	1.0
Silver	D011	5.0

Passing TCLP addresses toxicity for the substances tested. It does not approve reuse or rule out other reasons a waste may be hazardous. See material testing for sampling basics.

Anyone who handles solid waste must take reasonable steps to know its characteristics. For special waste, 20.9.8.11 NMAC requires the generator to document its makeup by lab analysis, process knowledge, or both. Analyses can include TCLP, the other RCRA characteristics, the paint filter liquids test, and other parameters NMED names. Special waste test methods must match permit requirements or have NMED approval before use.

Finding a reuse destination

EPA’s 2014 risk assessment found three uses protective of health and the environment for silica-based spent sand from iron, steel, and aluminum foundries: manufactured soil, soil-less potting media, and road subbase. EPA and USDA support those uses. The finding does not cover sand from brass or bronze foundries, olivine sand, or sand mixed with other foundry wastes such as baghouse dust or cupola slag. EPA defers to state programs, so the state rules on this page still decide each use.

New Mexico handles reuse through its solid waste definitions and facility rules. Check any destination and proposed use with NMED before scheduling delivery.

Ask the receiving facility for its NMED registration or permit, and confirm it covers spent foundry sand. Get the receiving site’s specifications and written acceptance. If reuse is not cleared, arrange disposal that fits the waste determination. Special waste must go to a facility permitted to accept it.

Worker protection

Silica: foundry sand is mostly crystalline silica. OSHA’s general industry standard, 29 CFR 1910.1053, sets a permissible exposure limit of 50 µg/m³ of respirable crystalline silica as an 8-hour average. Exposure assessment starts at the 25 µg/m³ action level.
Construction use: crews placing sand as fill or subbase fall under the construction silica standard, 29 CFR 1926.1153.
Lead: brass and bronze foundries that cast leaded alloys also follow OSHA’s lead standard, 29 CFR 1910.1025.
Dust: control dust during shakeout, storage, and loading.

New Mexico Occupational Health and Safety Bureau runs New Mexico’s OSHA-approved State Plan. For most employers, its standards apply in place of federal OSHA and must be at least as effective.

Storage and records

Store spent sand on a defined pad or in bins, control dust and runoff, and keep other foundry wastes out. Under 20.9.2.8 NMAC, store solid waste and recyclable materials so they do not cause blowing litter, harbor pests, or create a nuisance or health hazard.

If your sand is special waste, keep it in a designated special waste storage area for no more than 90 days, unless NMED approves longer. Label full containers with the generator’s name and address, the contents, the storage date, and the hazards.

A registered recycler that accepts no solid waste must keep records showing that, after an initial accumulation period, it recycles at least 75 percent of its inventory each year (20.9.3.29 NMAC).

Keep the waste determination, lab reports, NMED correspondence, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations. For special waste, keep the originating manifest and the returned signed copy for three years.

Before pickup

Identify the alloys cast, sand and binder systems, separate streams, monthly volume, and plant location.
Make the hazardous waste determination and complete the required tests.
Choose a destination and get its material specifications.
Confirm the classification with NMED, and confirm the receiving facility is registered or permitted for the sand.
Get written acceptance and arrange pickup.

Common questions

Is a passing TCLP test enough?

No. It answers a toxicity question for the substances tested. The full waste determination, NMED’s rules, and the receiving site’s specifications still apply.

Does EPA’s risk assessment approve our sand?

No. It supports three soil-related uses for silica-based sand from iron, steel, and aluminum foundries. NMED’s rules still decide each use in New Mexico.

Is spent foundry sand special waste?

It can be. Special waste includes industrial solid waste that may harm the environment or public health unless specially handled. The rule lists foundries among the sources of industrial solid waste. Ask NMED how your sand is classified.

Does the receiving recycler need NMED approval?

Yes. A recycling facility that accepts only source-separated recyclables registers with NMED and renews every five years. A facility that also accepts solid waste, or processes it, needs a permit.

How long can special waste be stored?

No more than 90 days from the date it is placed in storage, unless NMED approves otherwise.

How long do we keep special waste manifests?

The generator keeps the originating manifest and the returned signed copy for three years.