Aggregate Resource Potential of the Okanagan Area - Digital Data

This file (legend.txt) details the methodology and procedures used in determining the 
aggregate resource potential of the Okanagan Area (NTS sheets 82E/3, 4, 5, 6, 11, 12, 
13, 14, and 82L/3, 4, 5, 6, 11, 12, 13, 14).  The 1:50,000-scale data are defined as 
Level III aggregate resource potential maps (Bobrowsky et al., 1996).  The results are 
published in digital form only and should be cited as: 

   P.T. Bobrowsky, PGeo, N.W.D. Massey, PGeo., and A. Matheson, PGeo. (1998); 
  	Aggregate Resource Potential of the Okanagan Area (NTS 82E(west) and 82L(west)), 
	B.C. Ministry of Energy and Mines, Open File 1998-5 (digital data).


Assessment of Aggregate Resource Potential

Within the Okanagan area, 3400 individual areas (polygons) have been assessed for hosting
potential natural aggregate resources.  The polygons are based on soil and landform units
identified and delineated by Kowall (1986) and Wittneben (1989), with additions and 
modifications by the authors.  The potential has been assessed by compiling data for each
of the original 3400 landform polygons.  Each parameter contained several classes used to 
rank polygons (see table below and Bobrowsky et al., 1996).  Data for factors and rankings
have been included as attributes for the landform polygons in the digital files.

Geological Factors

The factors used to assess the potential of a polygon to host aggregate are:

1) Landform type: aggregate deposits occur in certain favourable environments which 
	can be interpreted from the observable landforms.  The ranking was assigned for both 
	major (Geol1) and secondary (Geol2) landform designations within an area 
	(rankings - G1_rank and G2_rank).
2) Texture of soil type: The soil association developed upon a landform has been rated by 
	Kowall (1986) for the proportion of gravel-sized (>2mm) particles.  Similar ratings 
	were determined for other polygons.  Rankings were assigned for both dominant 
	(Texture1) and secondary (Texture2) soil associations (rankings - T1_rank, T2_rank).
3) Area: the areas of non-water landform polygons range from 0.07 to 4485.9 ha (Area).  
	They have been ranked (Area_rank) such that roughly equal numbers of landform 
	polygons fall within each group.  No allowance has been taken for partial polygons 
	that occur at the edges of the project area.
4) Pits: each polygon was ranked for the presence or absence of aggregate pits within it 
	(Pit_rank).  No importance was attached to actual numbers of pits within a 
	polygon (Pits).  
5) Overburden thickness: The thickness of overburden which must be removed before 
	extraction of aggregate can occur, is an important factor in evaluating the economic 
	importance of a potential deposit.  Data are derived from drill logs for water wells
	(data - Overburd; rankings - Over_rank)
6) Gravel Thickness and Volume: Where gravel is known to occur, the amount of gravel 
	is important for determining economic value.  However, very few volume estimates are
	available within the area, but thickness can be a useful alternative. Two databases 
	yielded information:
	i) Field inspection of existing aggregate pits (data - Thick_pit and Vol_pit; 
	rankings - Thp_rank and Vol_rank respectively).
	ii) Drill logs for water wells (data - Gravel _thi; rankings - Thick_rank)

**********Final Rankings

The final ranking of the landform polygons was achieved in a three-step process.

First, all polygons (220) which host present or historical aggregate pits were separated 
out and assigned a classification "H".  These represent 9.95% of the total area.

Second, unfavourable polygons were eliminated based on the rankings for those parameters 
considered most important for indicating aggregate resource potential.  Retained were 
those polygons with values of greater than 2 for g1_rank or g2_rank or thick_rank; or 
values of 5 for t1_rank or t2_rank.  From this subgroup, those polygons with over_rank 
equal to 1 were eliminated.  Eliminated polygons (1085) are classified "U" (Unclassified). 
They comprise 33.78% of the total area.

Third, the retained polygons (2095), deemed most favourable to host undiscovered aggregate 
deposits, were subdivided into three categories based on the weighted final rank score:

	Total Rank = 3*g1_rank + 3*g2_rank + 3*thick_rank + 2*over_rank + 3*pit_rank 
				+ area_rank + vol_rank

Values for the polygons ranged from 13 - 53.  The significance of a polygon for aggregate 
resources was assigned:

	Primary potential (class=1): Total Rank > 30
	Secondary potential (class=2): Total Rank 21 - 30
	Tertiary potential (class=3): Total Rank < 21

For the whole project area, 274 polygons are of primary, 552 of secondary and 1296 of 
tertiary potential.  These comprise 5.58%, 16.54% and 34.16%, respectively, of the total 
map area.


Table 1: Summary of values used to determine rankings of individual parameters

	Ranking         Geol          Texture       Area             Pit		
	                                            (ha)		  	       

	   5        Glaciofluvial       High        >679              -	     
			
	   4        Fluvial           Mod-high    398 - 679           -	     
	                              Variable
			  
	   3        Ablation Till     Moderate    238.6 - 398         -	    
	            Colluvium

	   2        Eolian            Low-mod     132.3 - 238.6       -	     
			Moraine

	   1        Glaciolacustrine    Low	        <132.2          present
	            Bedrock
	            Organic

	   0        Water             Unknown     (all water        absent
	            Urban Areas                    polygons)


	Ranking     Overburden  Thickness   Thickness       Volume 
	              (Well)      (Pit)      (Well)          (Pit)

	   5        0 - 1 m      >10 m        >27m       >1,000,000 m3
	            (0 - 3')                 (>87')
	   4        1 - 2 m     8 - 9 m     17 - 27 m   500,000 - 
	            (4 - 6')                (56 - 87')     1,000,000 m3
	   3        2 - 5 m     6 - 7 m     10 - 17 m    50,000 -
	            (7 - 16')               (34 - 55')       500,000 m3
	   2        5 - 10 m    4 - 5 m      5 - 10 m     5,000 -
	           (17 - 33')               (16 - 33')        50,000 m3
	   1         >10 m      2 - 3 m      0 - 5 m      0 - 5,000 m3
	            (>33')                  (0 - 15')
	   0        unknown     0 - 1 m      unknown        unknown
 
 




Notes:

Aggregate resource potential maps provide guidelines for testing, evaluating and managing 
aggregate resources within a defined area.  The maps are intended to provide first 
approximation estimates of broad, regional aggregate distribution.

Areas are ranked for their potential to host natural aggregate deposits (mainly gravel). 
Neither sand deposits nor crushed rock were considered.  Detailed groundwork, including 
mapping, drilling and geotechnical evaluation, is required to further locate, outline and 
estimate the quantity and quality of the deposit before its economic significance can be 
evaluated.

Rankings, both for individual parameters and final total ranking, are relative between areas 
within the project and cannot be compared directly to results from other study areas.

All data were used as presented by the agency responsible for a particular database.  The 
accuracy and integrity of those data are assumed.  

The authors and the Geological Survey Branch are not responsible for inaccuracies, omissions
and errors resulting from this work.


Sources of Information:

Soils and landforms:
	
	Kowall, R. 1986a; Soils of the Penticton Map Area 82E, Ministry of Environment, 
		Lands and Parks, Maps, scale 1:50,000.  Sheets:
			82E/03	Osoyoos
			82E/04	Keremeos
			82E/05	Penticton
			82E/06	Beaverdell
			82E/11	Wilkinson Creek
			82E/12	Summerland
			82E/13	Peachland
			82E/14	Kelowna

	Kowall, R. 1986b; Soils of the Vernon Map Area 82L, Ministry of Environment, 
		Lands and Parks, Maps, scale 1:50,000. Sheets:
			82L/03	Oyama
			82L/04	Short's Creek
			82L/05	Westwold
			82L/06	Vernon
			82L/11	Salmon Arm
			82L/12	Monte Creek
			82L/13	Chase
			82L/14	Sorrento

	Wittneben, U. 1989; Surficial Materials, Okanagan and Similkameen Valleys, Ministry 
		of Environment, Lands and Parks, Maps, scale 1:20,000.  Sheets: 
			82E 002, 003, 011, 012, 021, 022, 023, 031, 032, 033, 042, 043, 052, 
			    053, 062, 063, 072, 073, 082, 083, 084, 093, 094
			82L 003, 004, 013, 014, 023, 024, 025, 034, 035, 044, 045, 054, 055,
			    064 


Water well data:
	Water Management Division, Ministry of Environment, Lands and Parks, Victoria. 
		(enquiries phone: 250-387-9483 	or via Internet at 
			http://wtrwww.env.gov.bc.ca/wat/gws/gwis.html)

Other references:
	Bobrowsky, P.T., Massey, N.W.D. and Matysek, P.F. 1996; Aggregate Forum, 
		Developing an Inventory that Works for You!, Report of Proceedings, Ministry 		of Energy, Mines and Petroleum Resources, Information Circular 1996-6. 

	Matheson A., MacDougall, D., Bobrowsky, P.T. and Massey, N.W.D. 1997; Okanagan
		Aggregate Potential Project, in Geological Fieldwork 1996, Lefebure, D.V.,
		McMillan, W.J. and McArthur, J.G., Editors, British Columbia Ministry of 
		Employment and Investment, Paper 1997-1, pages 347 - 352.

	Matheson A., Paulen, R., Bobrowsky, P.T. and Massey, N.W.D. 1998; Okanagan
		Aggregate Potential Project, in Geological Fieldwork 1997, British Columbia 
		Ministry of Employment and Investment, Paper 1998-1, page 29a-1.









