Sand Mining in California's Central Coast Region

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An environmental summary created by the ENVS 560/L Watershed Systems class at CSUMB.

Image 1. CEMEX Lapis dredge pond. (Monterey County Weekly, Karen Loutzenheiser, Mar 24, 2016)
Image 2. An undated photo of the CEMEX Lapis dredge pond. (Gary Griggs, Ph.D, UC Santa Cruz).

This page gives a short history of sand mining in California's Central Coast Region and highlights the CEMEX Lapis Sand Plant. The page does not discuss gravel mining that occurs inland.


The only sand mining plant currently operating in California's Central Coast region, and the United States, is located in the City of Marina, Monterey County, California. The CEMEX Lapis Sand Plant is located on Lapis Road in Marina, eight miles north of Monterey, California along Highway 1 and within the Lower Salinas River Watershed. [1]. The area to the north and south of the CEMEX Lapis Plant primarily consists of undisturbed coastal dunes. The 400-acre property is situated between Martine Dunes owned by the Big Sur Land Trust (BSLT) to the immediate north and Marina Dunes Preserve immediately to the south owned byMonterey County Regional Park District.


Southern Monterey Bay Region in California's Central Coast was the most intensively mined shoreline in the United States from 1906-1990. [2] Southern Monterey beach sands have been valued for a wide variety of commercial uses because of the sand composition, hardness, roundness, color, and purity. [3] As many as six sand mines, including the current CEMEX Lapis Plant, were active at various times over the past century in City of Marina and City of Sand City. Mining at the CEMEX Lapis Plant property began between 1906/1907. The property was owned by a number of entries prior to CEMEX taking over in 2005. In the early 1900s, all six mines took sand directly off the beach but in 1959, beach mining ceased as mines started to use an ocean dragline, a claw or shovel attached to a cable that extracts sand directly from the ocean, below the mean tide line [4]. The previous CEMEX Lapis Plant property owner submitted an application to the Army Corps of Engineers, California State Lands Commission, and Monterey County and secured authorizations to construct a drag-line. However, a dragline was never installed. Instead, some time in the 1960s, a dredge was created on the property to extract sand via a manmade pond located approximately 1,400 feet inland of the ocean. [3][4] At the time, the dredge pond was about 200 feet wide by 300 feet long, with a depth of 38 feet. Around 1965, the dredge pond was moved to the beach near where it currently sites and its operation resulted in creating a new dredge pond. [4]

The majority of sand mines closed in 1990 due to assumptions that mining increased coastal erosion but the 400-acre CEMEX Lapis Plant was is the only sand mine in California that continues to operate. Best estimates suggest that the CEMEX Lapis Plant removes nearly 200,000-250,000 tons, possibly as much as 326,000 tons of sand annually (one dump truck every 20-30 minutes). [3][5] The extraction volume more-or-less equals the total volumes previously removed by all of the once-operating mines combined. [3] In 2016, the California Coastal Commission notified CEMEX of its intent to commence a cease and desist order for violations of the California Coastal Act. On 13 July 2017, the California Coastal Commission and CEMEX settled that CEMEX Lapis Plant will shut down operations by 31 December 2020 and avoid litigation. [6]. The agreement will end a more than century-long era of sand mining in the Monterey Bay.

CEMEX Settlement Agreement

Events leading up to the agreement to shut down operations by 31 Dec 2020.

  • 2010 - The California Coastal Commission decides to look at CEMEX Lapis Plant under the microscope following allegations from the public that the property owner was using bulldozers to push sand into the dredge pond. [7]
  • 2014 - The California Coastal Commission begins a series of meetings phone calls, and site visits with representatives of the CEMEX Lapis Plant property owner. [7]
  • 2016 Mar 15 - The Marina City Council adopts a resolution authorizing the City Manager to request that the California Coastal Commission assist and coordinate with the City in any enforcement proceedings pursued in relation to possible violations of the California Coastal Act and the Marina Local Coastal Program by the CEMEX Lapis Plant sand mining operations. [8]
  • 2016 Mar 17 - The California Coastal Commission commences proceedings to issue a Cease and Desist Order and a Restoration Order for the imposition of administrative civil penalties and to resolve the violations of the Coastal Act resulting from unpermitted development that has and continues to occur on the CEMEX Lapis Plant property. Unpermitted activities at the property include dredging and extraction of sand, placement of floating dredges and development associated with the dredges (installation of anchors, cables, pipes, and pump station(s)), grading, and changes in the intensity of use of the mine. [7] The commission also begins a series of confidential discussions with the representatives of the property owner about its operations. [9]
  • 2017 Feb 3 - Marina City Mayor, Bruce Delgado sends a letter to the State Lands Commission urging the agency to assert its jurisdiction and require that CEMEX obtain necessary permitting from the State Lands Commission for any continued sand mining activity at the CEMEX Lapis Plant. [8]
  • 2017 May 16 - The State Lands Commission issues a letter to CEMEX stating that sand in the dredge pond comes in with the tides and so is subject to the agency’s jurisdiction. CEMEX must either immediately submit a lease application, conduct environmental studies, and pay royalties, or cease dredge pond operations or face civil liability and damages because of the financial and resource impacts of its operations on the state. Specifically, the State Lands Commission noted that “the intensity of sand extraction at the Lapis operation causes environmental damage, public and private property damage, and loss of economic benefit through beach erosion.” [7]
  • 2017 June 6 - The Marina City Council adopts a resolution to find the CEMEX Lapis Plant meets the elements required to be considered a public nuisance. [8]
  • 2017 June 27 - The California Coastal Commission and CEMEX reach a proposed settlement (Consent Cease and Desist Order No. CCC-17-CD-02) to end its sand mining operations, pending approval by 12-member commissioners at its 2017 July 13 meeting. [9] [4] The agreement is a result of more than a year of negotiations between CEMEX and commission staff, and forecloses any possible litigation. “We have spent countless hours in confidential talks forging a solution to stop the truly regrettable loss of sand and to protect the beaches in the Monterey Bay,” said the commission’s Chief of Enforcement Lisa Haage. Per the agreement, CEMEX agrees to the following:
    • Stop extracting sand from the last beach sand mining operation in California.
    • Resolve its financial liabilities under the California Coastal Act.
    • Withdraw any claims CEMEX may have to a vested right for continued sand mining on the property.
    • Cease all sand mining operations by 2020 Dec 31. The maximum amount of sand that may be removed during the three year cessation period is 240,000 tons or approximately 177,000 cubic yards per year. The agreement also provides another three years without any additional sand extraction to allow CEMEX to wind down all operations, assist with employee transitions, and restoration and reclamation activities to encourage the recovery of the habitat values.
    • A deed restriction will be placed on the property at sale to protect it in perpetuity and provide for public access and conservation at the site, and provides for a transfer of the site at a reduced price to a non-profit or governmental agency approved by the Commission.
    • CEMEX will be monitored regularly and will be fined for any breach of agreement.
  • 2017 July 13 - At the monthly California Coastal Commission meeting, nine of the twelve Commissioners votes unanimously (3 of the members were absent) to approve the settlement agreement and shutdown the CEMEX Lapis Plant by 2020 Dec 31. [10]

Systems and Processes

Sand is a valuable part of the coastal land and dune ecosystem and is not a renewable resource. [11] The Monterey Bay tidal system moves sand along the shore, therefore sand removed from one location impacts the entire shoreline.[12] Sand mining is one of two major regional activities that have changed the sand supply into the Southern Monterey Bay (SMB) Littoral Cell, which extends from the breakwater in Monterey north to the head of Monterey Submarine Canyon [3]. Historically, the Salinas River contributes sand to the SMB cell however, dams on the Salinas River and movement of the river mouth have reduced the amount of sand brought into the cell; the dams trap about 33% of the sand load. [3][13] As such, the Salinas River no longer yields significant sand to nourish southern Monterey Beaches. CEMEX Lapis Plant mines sand originating from the Salinas River, and the amount of sand removed vastly exceeds the amount of coarse-grained sand added into the cell from the Salinas River. Eroded dune sand primarily collects in a dredge pond, a 1,000 square feet artificial lagoon or "sink" in the shoreline on the property. [3] Every year, the pond fills with sand carried by winter waves or wind. Sand mined from the pond is removed directly from the cell and the cycle repeats. The CEMEX Lapis Plant mines an estimated 326,000 cubic yards of sand per year and removes roughly 50 percent or more from the SMB Littoral Cell sand supply and budget. [5] Between 1986 to 2013, CEMEX mined more than 6.8 million cubic yards (8.4 million tons) of sand that will never return to the coastal system.

A general argument is that mining diminishes sand deposits on beaches and accelerates coastal erosion. Sand mining in coastal dune systems can lead to long term erosion of approximately 0.5 to 1.5 meters per year. [14] The southern Monterey shoreline on average is the most erosive shoreline in California. [15] Erosion rates are highest in the north, closer to the sand mine and decrease southward.

Erosion Rates in Southern Monterey Bay: [16]

The volume of sand eroded annually on average from a bluff was determine by using 8 miles of bluff from the CEMEX Lapis mine to Del Montey Beach. Along this 8-mile stretch, the average retreat rate is 4 ft/year and totals 250,000 cubic yards/year which is essentially the same volume of sand removed by the CEMEX Lapis Plant. Reductions in erosion and dune retreat are expected should mining stop, as more sand would be contributed to the littoral cell and move down the coast. [13] Without the sand plant, the coast in Southern Monterey Bay would erode by roughly 1-2 feet a year, if not less, based on regular tidal action.

Laws, Policies, & Regulations

CEMEX claims that because its operation precedes the California Coastal Act of 1976, it had vested rights to continue mining sand without acquiring further permits. [8] However, the California Coastal Commission found that the illegal dredge pond on site and an increase in extraction activity overstep the bounds of the vested rights. [7] According to the California Coastal Commission, mining sand from the beach at Marina conflicts with the California Coastal Act in the following ways [13]:

  • Impacts on the local sand supply, in conflict with Section 30235.
  • Habitat degradation and landform alternation, in conflict with Section 30231, 30240, and 30251.
  • Visual intrusion to the beach environment, in conflict with Section 30251.
  • Degradation of sand dunes creates a barrier to beach access, in conflict with Section 30211.

The agreement for the closure of the CEMEX Lapis Plant has several conditions for the future of the property, including a restricted deed so that the land must be purchased primarily for conservation purposes and will include public access. [6]

The City of Marina put out a request for proposals for a Local Coastal Plan update, in which one task includes drafting a vision for the reuse of CEMEX Lapis Plant property. [17]

Resources At Stake

Image 3. Economic losses. Philip G. King, Ph.D, 2017 [18]

Excavation of approximately 326,000 tons of sand each year can impact the following resources along the Monterey Bay shoreline:


  • A valuable resource that is used to make glass, computer chips, in cement to build houses and roads, and more. [19]
  • Provides protection from extreme conditions (i.e. flood, large storms, sea level rise)

Water supply

  • Sand mining can extend so deeply that it affects ground water, springs, underground wells through lowering of the water table. [20]

Species Biodiversity

Habitats and Ecosystems

  • Sub-tidal habitat (rocky reef, kelp forests, eelgrass beds)
  • Coastal/Sandy Beach habitat
  • Dune habitat

Public access of beaches and dunes for recreational use


  • Existing coastal development (hotels, condos, etc.)
  • Highways & Bridges (HWY 1)

Special Status Plants known to occur on the CEMEX Lapis Plant property - sandmat manzanita (Arctostaphylos pumila), Monterey spineflower (Chorizanthe pungens var. pungens), sand-loving wallflower (Erysimum ammophilum), Menzies' wallflower (Erysimum menziesii), Monterey gilia (Gilia tenuiflora ssp. arenaria). [21]

Special Status Animals known to occur on the CEMEX Lapis Plant property - black legless lizard (Anniella pulchra nigra), western snowy plover (Charadrius alexandrines nivosus), Smith's blue butterfly (Euphilotes enoptes smithi), bank swallow (Riparia riparia). [21]

  • In December 2014, CalAm began work on a test slant intake well located at the property [22]. Due to the presence of threatened western snowy plover breeding grounds near the test slant well, the location had to be returned to its original conditions by 2018 Feb 28 [23].


Various private and public organizations have interests in sand mining. Some of these are:

Local Government


  • CEMEX- Mexico-based, global building materials company which owns the CEMEX Lapis Plant.



Education Institutions


Coastal Retreat in California's Central Coast Region, specifically Southern Monterey Bay, has the fastest rate of erosion in California.[15] Since the retreat is occuring in the Monterey Bay National Marine Sanctuary, scientists are determined to find possible mitigation efforts, reasons for high rates, and, specific hot spots.

Recent research includes:

  • Thorton et al. (2006) looked at sand mining impacts on long-term dune erosion in southern Monterey Bay. [2]
  • Storlazzi and Field (2000) studied sediment distribution and transport along the Monterey Peninsula and Carmel Bay. [24]
  • Coastal Regional Sediment Management Plan For Southern Monterey Bay prepared by Williams et al. (2008). [25]
  • Hapke et al. (2006) wrote the National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast. [15]


There are a variety of tools that can be used to assess the effects of sand mining and/or coastal retreat.

  • ArcGIS and the Digital Shoreline Analysis System (DSAS) toolbox can be used to monitor changes in beach width.
  • Stereo Photogrammetry [2]
  • LIDAR Measurements [2]
  • GPS Surveys [2]
  • Historical aerial photography

Future Research

The Coastal Regional Sediment Management Plan for Southern Monterey Bay lists potential ways to address the issue of coastal erosion.

Continued study of beach erosion rates in the Southern Monterey Bay after the shutdown of the CEMEX plant will help confirm the impacts of sand mining. CSUMB is planning to continue erosion studies at the site.

CEMEX In The News


  1. CEMEX Lapis Plant
  2. 2.0 2.1 2.2 2.3 2.4 Thornton et al. 2006. Sand Mining Impacts on Long-term Dune Erosion in Southern Monterey Bay. Marine Geology 229.1:45-58.
  3. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 Testimony to California Coastal Commission on Sand Mining in City of Marina
  4. 4.0 4.1 4.2 4.3 Staff Report: Recommendations and Findings for Consent Settlement Agreement and Cease and Desist Order
  5. 5.0 5.1 An Evaluation of the Ongoing Impacts of Sand Mining at the CEMEX Lapis Sand Plant in Marina, California on the Southern Monterey Bay Shoreline
  6. 6.0 6.1 [ California Coastal Comission. 2017. CONSENT SETTLEMENT AGREEMENT AND CEASE AND DESIST ORDER CCC-17-CD-02. State of California Natural Resources Agency.]
  7. 7.0 7.1 7.2 7.3 7.4 Notification of Intent to Commence Cease and Desist Order and Restoration Order Proceedings and Administrative Civil Penalties Proceedings
  8. 8.0 8.1 8.2 8.3 Finding the current operation of the CEMEX mine meets the elements required for a Public Nuisance
  9. 9.0 9.1 Coastal Commission Staff and CEMEX reach proposed settlement to close sand mining operations
  11. [1]
  12. Sierra Club - Beach Erosion caused by CEMEX sand mining in Marina
  13. 13.0 13.1 13.2 Coastal Processes affecting the Southern Monterey Bay (SMB) Littoral Cell With focus on the CEMEX Mine at Marina, CA
  14. [2]
  15. 15.0 15.1 15.2 Hapke CJ et al. 2006. USGS. National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast
  16. California Coastal Erosion Response to Sea Level Rise
  17. [ City of Marina.2017. Request for Proposals. Local Coastal Plan Update Preparation of Sea Level Rise Vulnerability Assessment, Risk Assessment, and Adaptation Planning.]
  18. Economic Analysis of Proposed Cessation of Sand Mining in Marina, CA
  19. Sand Wars Movie Website
  20. Environmental Impacts
  21. 21.0 21.1 CEMEX: Ecological Resources
  22. In brief: Test slant well intake for Monterey Peninsula project now underway
  23. MPWSP Temporary Slant Test Well, Project Description
  24. Storlazzi, CD and Field, ME. 2000. Sediment distribution and transport along a rocky, embayed coast: Monterey Peninsula and Carmel Bay, California. Marine Geology 170.3: 289-316.]
  25. Coastal Regional Sediment Management Plan For Southern Monterey Bay



This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.