Enter a name, company, place or keywords to search across this item. Then click "Search" (or hit Enter).
Collection: Directories and Documents
Mineral Land Classification of Nevada County, California (1990) (235 pages)
Go to the Archive Home
Go to Thumbnail View of this Item
Go to Single Page View of this Item
Download the Page Image
Copy the Page Text to the Clipboard
Don't highlight the search terms on the Image
Show the Page Image
Show the Image Page Text
Reset View and Center Image
Zoom Out
Zoom In
Rotate Left
Rotate Right
Toggle Full Page View
Flip Image Horizontally
More Information About this Image
Get a Citation for Page or Image - Copy to the Clipboard
Go to the Previous Page (or Left Arrow key)
Go to the Next Page (or Right Arrow key)
Page: of 235
concrete. However, the economics of processing these deposits to
produce such products would have to be evaluated on a sitespecific basis.
Also included in the older alluvial deposits are the rocks
of the Mehrten and Valley Springs formations in the western and
central parts of the county. These volcanic-sedimentary units
are included here because of the abundance of mudflows, breccias,
volcanic sediments, and conglomerates in these formations in the
western and central parts of the county. No commercial
production of construction aggregate from these formations occurs
in Nevada County and it is unlikely that material from these
formations could be used for portland cement concrete or
asphaltic concrete; however, exploration and testing might find
areas in these formations suitable for use as subbase or base
materials.
In the eastern part of the county the older alluvial
deposits include older stream and terrace deposits. These
deposits are similar to recent alluvial deposits in eastern
Nevada County but are older and therefore may be more weathered.
This weathering, if present, commonly decreases the physical
strength of the clasts and may make the material suitable only
for uses in which high physical strength and durability are not
specified. If weathering is severe enough, the material may be
rendered unsuitable for use as construction aggregate. No
current production of aggregate occurs from these units. However,
old borrow pits exist in some of these formations, indicating the
materials have been used for construction aggregate in the past.
Testing would be required to determine the highest use for which
these materials would be suitable.
Areas Classified MRZ-2a (S&G)*
MRZ-2a (S&G)*' Bear River/Lake Combie Area: This property was
previously classified MRZ-2 for sand and gravel resources by the
Division of Mines and Geology (DMG OFR 83-28 SAC, 1983) and this
classification has not been altered in this report. The area
classified includes Lake Combie and a portion of the Bear River
above Lake Combie along the border between Nevada and Placer
counties. Mining has been conducted at this site since 1946.
The Joe Chevreaux Company currently mines this deposit and
produces construction aggregate for a variety of uses up to and
including portland cement concrete. Additionally a variety of
specialty products are mined and marketed from this deposit
including engine, refractory, abrasive, and filtration sands.
The aggregate processing operation is in Placer County. The
deposit consists of recent alluvial materials derived from
deposits of older Tertiary gravels and hydraulic mine tailings
located upstream.
MR2Z-2a (seq) ** Bear River/Steephollow Creek Area: The area
classified includes the portion of the Bear River from the Dutch
Flat area downstream to the inlet of Rollins Reservoir and
Steephollow Creek from Steephollow Crossing to the Bear River.
Dal