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 [graphic] National Register Bulletin Guidelines for Identifying, Evaluating and Registering Historic Mining Sites

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U.S. Department of the Interior, National Park Service

Ball Mill at the Socorro Mines
As a potential source of information about technological innovation, mining machinery should be discussed in the description section of a National Register nomination. This ball mill at the Socorro Mines at Catron County, New Mexico was used in the cyanide processing of ore.(Chris Wilson)


How to Complete the National Register Registration Form and How to Complete the National Register Multiple Property Documentation Form contain specific instructions for completing individual and multiple property nominations. The following discussion will focus on special considerations related to the nomination of mining properties. This discussion begins with a brief overview of the different nomination formats and the circumstances under which one format may be employed instead of another.

The National Register lists individual properties, including districts, sites, buildings, structures, and objects. Multiple property submissions contain groups of properties, which are related by common historical associations or physical characteristics and which are nominated under a single "cover document."

The National Register Registration Form (NPS Form 10-900) should be used for the nomination of individual districts, sites, buildings, structures, and objects related to mining. This format is used in situations involving the nomination of an individual standing structure or building such as a single powder shack, mill, or headframe. However, individual mining resources generally do not exist in isolation. Based on the premise that individual mining resources will usually serve as single elements of larger mining systems, only a relatively small percentage of mining resources will be nominated as individual buildings or structures.

Given the prevalence of mining systems, the historic district is a common framework for nominating a concentrated assemblage of related mining resources to the National Register. The National Register defines a district as follows: "A district possesses a significant concentration, linkage, or continuity of sites, buildings, structures, or objects united historically or aesthetically by plan or physical development." This definition aptly describes many mining properties. Most potentially eligible mining properties do not consist only of a single resource, but rather will include a discrete historical area containing a grouping of functionally related resources that all played a part in the extraction, refinement, and production of minerals. Historic districts are nominated on the National Register Registration Form. A discontiguous district may be relevant to the nomination of mining properties. A discontiguous district is composed of two or more definable significant areas separated by nonsignificant areas. According to the National Register Bulletin on How to Apply the National Register Criteria for Evaluation a discontiguous district is most appropriate where

  • elements are spatially discrete;
  • space between the elements is not related to the significance of the district; and
  • visual continuity is not a factor in the significance."

These three factors could apply to many mining properties. Given the large-scale nature of certain mining activities, elements of many mining systems will be separated by spaces unrelated to the significance of the district. Among many possibilities, discontiguous districts may be most appropriate for the nomination of mining properties involving linear systems like tramways, ditches, and flumes. Ditch and flume systems, for example, may have periodically terminated by dumping water into streams. Water may then be diverted back into the same system several miles downstream. In this case, the stream itself may not be included in the district, but the ditches and flumes would be elements of a discontiguous system.

In another example, an aerial tramway originally built to transport copper ore to a smelter several miles away might be nominated as a discontiguous district containing both the tramway and the smelter. Although first built as a linear system, many elements of the system may have lost integrity today. All the tram towers may have been removed and the entire tram route may be covered with forest growth not present during the period of historic significance. However, the copper mine, the smelter, and several tram tower pads may remain clearly visible today. These elements of the original tram system could be nominated as a discontiguous district. A discontiguous district is nominated on a National Register Registration Form.

The Multiple Property Documentation Form (NPS Form 10-900-b) is used to document a group of significant properties linked by a common historic context. The Multiple Property Documentation Form is not used to nominate properties, but provides a historical overview, defines property types related to the overview, and outlines the significance and registration requirements for the property types. Individual properties associated with the historic context are nominated on a National Register Registration Form. An example might involve several gold mines dispersed across a given county, all of which produced ore for refinement at a mill located some distance away from each of the mines. The historic significance of the mines and the mill could be outlined in a historic context titled "Gold Production in Grand County, 1874-1893." In terms of property types, all the mines can be classified as an extraction property type and the mill could be categorized as a beneficiation property type. The registration requirements for property types establish a benchmark for defining eligibility for listing.

The historic context documentation pertaining to "Gold Production in Grand County" and related property type information is included on the Multiple Property Documentation Form. Within the multiple property framework, separate nominations for each of the individual mines, the mill, and any historic districts must be prepared using registration forms (NPS Form 10-900). The advantage of this approach is that one "cover document" can be used to expedite the documentation and nomination of a number of separate properties.

Because mining properties are often large and complex resource types, several historic contexts may be required to convey the overall significance of a mining property. However, nominations can be submitted before all associated historic contexts have been documented. Once a single historic context has been documented on a Multiple Property Documentation Form, related property nominations can be prepared and are submitted to the National Register. When other historic contexts are documented and property nominations completed, these can be submitted to the National Register at a later date as amendments to the original Multiple Property Documentation Form. Thus, the multiple property format offers a flexible mechanism for nominating groups of mining properties over a period of time.

Situations will arise where individuals involved in the preparation of nominations will ask whether a historic district nomination is most appropriate for a given mining property or whether a multiple property nomination ought to be undertaken. A multiple property submission will usually be appropriate in cases where separate mining resources are related by a common historic context or theme, but are spatially separate. An example would involve several mine properties associated with a mill where all the ore within a mining region was brought for refinement. In spite of the obvious historic association between the mines and the mill, it may be that the transportation systems leading from the mines to the mill have lost their historic identity over the years. Another possible scenario would involve a case where the same hypothetical mill is located so far away from the mining property that creating a historic district is not justified. In these situations, nominators should adopt the multiple property format.

A district nomination generally will be appropriate in cases where all of the elements of an intact mining system are located within a contiguous geographic area. The size of such an area might vary from a small parcel of less than one acre, which includes a few buildings and a mine shaft opening, to a broad expanse extending over a thousand acres and including mines, mills, tramways, flumes, roads and other related pieces of machinery and equipment. In addition, all the elements of the district must retain their historic associations with one another.

Whether preparing individual property nominations or multiple property nominations, the National Register Registration Form plays a role. Several sections of the registration form are of particular importance when nominating mining properties. These sections include #7 (description), #8 (significance), and #10 (boundaries). Each of these elements of the individual form will now be examined in greater detail.

Section 7: Description

The description section of an individual registration form should begin with an introductory paragraph that briefly describes the property, notes its major physical characteristics, and assesses its physical integrity. Additional paragraphs should support the introductory paragraph and provide a more detailed description of the property. This additional material should also discuss the property's historic and current condition, and identify and date of any alterations, additions, or other changes that have affected the historic evolution and integrity of the property. Other specific issues that should be addressed in describing mining properties will include discussion of the following:

  • Natural features that contributed to the original decision to conduct mining activity in the area.
  • Any landscape modifications associated with historic mining activity (i.e., tailings piles, gob piles, etc.).
  • Deterioration due to vandalism, neglect, lack of use, or severe weather, and the effect it has had on the property's historic integrity.
  • Original and other historic machinery still in place.
  • Linear systems within the property such as canals, ditches, railroads, railroad beds, roads, and tramways including their approximate length and width and the location of terminal points.

If the mining property is nominated as a historic district, the description section also should discuss whether or not all the individual components of the resource contribute to the significance of the historic district. In determining whether district resources are contributing or noncontributing, consider specific information about each resource including its period of significance, function, association, information potential, and physical characteristics. All resources should be keyed as contributing or noncontributing on a sketch map submitted with the form.

Section 8: Significance

The statement of significance should begin with a paragraph summarizing the significance of the mining property. This paragraph should explicitly discuss how the property meets the National Register criteria, including the criteria considerations, and how it represents all periods and areas of significance indicated on the form. The opening paragraph should be followed by a discussion of the property's historic context. Additional facts directly pertaining to the property's eligibility may be included to establish a property's significance, integrity, or ability to meet one or more criteria considerations.

Questions tend to arise about the required length of the historic context documentation. In general, the National Register does not mandate that a particular amount of documentation should accompany each nomination. Sufficient information should be provided to justify the significance and eligibility of the nominated properties. However, the length of the context statement will vary depending upon the nomination format.

Mineral Point, Wisconsin
During the nineteenth century immigrants from mining regions throughout the world arrived in the new mining fields of America. Among these immigrant groups were the Cornish, who used their homeland building techniques to establish communities such as the upper Mississippi River lead district town of Mineral Point, Wisconsin, shown here. Ethnic group contributions to the development of a mining area should be described in the significance section of a nomination. (State Historical Society of Wisconsin)
The multiple property format requires that historic context material be included in the multiple property documentation form. This means that individual nominations submitted as part of a multiple property package need only include a description, a brief historic context statement pertinent to that property, and an indication of how the nominated resource meets the registration requirements established for measuring the significance of the property type. However, properties nominated without a multiple property cover form will have to contain sufficient context information within the nomination to support registration.

When explaining the significance of mining properties, the following types of questions should be addressed:

  • How do the extant vestiges of mining functions or processes relate to the broader mining or technological development of the locality, region, State, or nation?
  • How important were the entrepreneurs, engineers, laborers, ethnic groups, and others who contributed to the development of the mining operation?
  • How do the remaining buildings, structures, sites, objects, and historic districts reflect significant mining production processes?
  • How did the mining operation(s) impact or influence other activities within a region or locale, such as exploration, settlement, and/or other commercial development-related activities?
  • How is evidence of historic mining activity reflected in the archeological record?

Section 10: Boundaries

All mining property boundaries should be plotted on USGS topographic maps. These maps will be included with the nomination documentation. Because of the complexity of many mining properties, a separate sketch map (preferably drawn to a scale of 1 inch equals 200 feet) may help to clearly identify both the boundaries and the resources within those boundaries. Resources within sketch map boundaries should be labeled as contributing or non-contributing. These resources should also be cross-referenced to the description section (Section 7) of the nomination.

Mining property boundaries should be selected to encompass, but not exceed, the full extent of the resources making up the property. Boundaries for a single parcel of land should encompass the significant concentration of buildings, sites, structures, or objects which comprise the mining property. Byproducts of mining activity, such as tailings piles, should be included within property boundaries.

In nominations involving discontiguous historic districts, a separate boundary should encompass each discontiguous element of the district. Each discontiguous element should be plotted on a USGS map, even though several maps may sometimes have to accompany the nomination. If necessary, separate sketch maps may be submitted for each discontiguous element.

In some instances, legally recorded mineral patent applications will help to determine the appropriate boundaries for a mining property. Such material can help to develop verbal boundary descriptions and to accurately plot the location of mining properties on the USGS maps that must accompany each National Register nomination. If available, these patent applications may be found in county courthouses, state geological offices, or in Bureau of Land Management offices.

The above-ground portion of a mining property will often be considerably smaller than portions of the property located beneath the surface of the earth. Because of the potential dangers involved, field investigators should not attempt to verify this fact by exploring underground mines. Underground investigation should only be attempted in those very rare cases when a State mining inspector has certified that a mine is safe to enter. As a general rule, however, exploration of underground mines should be avoided.

In some cases, written records may contain information about the extent of an underground mine. If so, this knowledge should be utilized when determining the above-ground boundaries of the property. Such information should be used to define above-ground boundaries that encompass the extent of the underground reaches of the mine. This will help to protect the full extent of the mining property by assuring that development projects only occur outside the property boundaries. In addition, such measures will help to ensure that new development does not take place in areas where ground subsidence is likely to occur. In many cases, however, boundaries will relate only to the mining resources visible on the surface of the ground.

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